musculoskeletal ultrasound 2007 vol.2 issues 4 2008-05-16 1416043756 jon a. jacobson saunders

U L T R A S O U N DC L I N I C S

Ultrasound Clin 2 (2007) xi–xii

xi

Preface

Jon A. Jacobson, MD

Guest Editor

1556-858X/07/$ – see front matter ª 2007 Elsevier Inc. All rightsultrasound.theclinics.com

Jon A. Jacobson, MDDivision of Musculoskeletal RadiologyUniversity of Michigan1500 East Medical Center Drive, TC-2910LAnn Arbor, MI 48109-0326, USA

E-mail address:[email protected]

Over time, since its first use in evaluation of themusculoskeletal system, ultrasound has becomemore accepted and its applications more diverse.This continued growth relates to advances intechnology and awareness that this imaging meth-od has a definite role in the diagnosis of musculo-skeletal pathology. Indeed, musculoskeletalultrasound should be viewed as another importantimaging tool, along with MR imaging, CT, andradiography. From the point of view of a radiologist,the more tools available to image the musculoskel-etal system, the more musculoskeletal pathologycan be effectively diagnosed.

While musculoskeletal ultrasound can demon-strate pathology seen on other imaging studies,such as MR imaging, ultrasound should be viewedas a complementary tool rather than one thatcompetes with MR imaging. The choice of ultra-sound versus MR imaging depends upon manyfactors, such as access, expertise, expense, clinicianpreference, the anatomical area imaged, and thepathology suspected. The use of ultrasound shouldfit a logical algorithm that takes all of these issuesinto consideration. For example, in an olderindividual with shoulder pain, one algorithm

would be to start with radiography and, dependingon the findings, continue with ultrasound. If thediagnosis is still unclear, then continue with MRimaging. In contrast, the evaluation of shoulderpain in a young athlete, one should considerradiography and then MR arthrography, given thelikelihood of cartilage pathology. There are indica-tions where ultrasound should be the primaryconsideration. One area is the evaluation ofdynamic pathology that requires joint movementor positioning, such as snapping or dislocatingstructures.

One of the reasons for the relatively slow growthof musculoskeletal ultrasound compared to MRimaging is the time and effort required to learn andperform this imaging method. For musculoskeletalultrasound to succeed in a busy imaging practice, Ibelieve that musculoskeletal ultrasound technolo-gists must be at the forefront, performing theexamination and acquiring images. However, it isvital that both the technologist and physician areskilled in musculoskeletal ultrasound. The purposeof this issue of Ultrasound Clinics is to review thecurrent and most common applications of muscu-loskeletal ultrasound.

reserved. doi:10.1016/j.cult.2008.03.002

http://www.ultrasound.theclinics.com

Prefacexii

It is my honor to be invited as the Guest Editor forthis issue of the Ultrasound Clinics. I am fortunatethat the leading experts in musculoskeletal ultra-sound have agreed to contribute. In this issue, aftera brief introduction, tendon and muscle pathology,is reviewed with Drs. Finlay and Friedman discus-sing upper extremity and Dr. Miller discussing lowerextremity. This is followed by discussions ofligament abnormalities by Dr. Craig and musculo-skeletal infection by Drs. Mossa-Basha and vanHolsbeeck. Dr. Martinoli and colleagues thendiscuss applications of ultrasound in evaluation ofperipheral nerves. Dr. Shiels shares his immenseexperience with foreign bodies in the next article,including percutaneous foreign body removal.

A comprehensive review of soft tissue masses isauthored by Drs. Adler and Hwang. The importantrole of ultrasound in evaluation of dynamic imagingis reviewed by Drs. Khoury and Cardinal, whosearticle includes real-time video clips availablethrough an Internet Web link. Drs. Jamadar andFranz then review the always challenging topic ofinguinal region hernias. Dr. Lopez-Ben discusses theuse of ultrasound in assessing synovitis and ero-sions, an important application in assessment ofinflammatory arthritis. Lastly, Drs. Fessell and vanHolsbeeck review interventional musculoskeletalultrasound, which includes techniques in jointaspiration. I hope that you find the material bythese leading authors enjoyable and educational.


Ultrasound Clin 2 (2007) 569–576

569

Introduction to MusculoskeletalUltrasoundJon A. Jacobson, MD

- Ultrasound equipment- Scanning technique- Normal sonographic anatomy- Artifacts

- Special ultrasound techniques- Musculoskeletal applications- Summary- References

Since the initial application of musculoskeletal addition, linear transducers are used in musculo-
ultrasound in evaluation of the rotator cuff in1977 [1], popularity of this imaging method has in-creased markedly as well as the number of acceptedapplications. Such advances primarily have beenlinked to improvements in technology, whichnow allow exquisite visualization of structures assmall as individual peripheral nerve fascicles [2].Essentially all soft tissue structures of the extremi-ties and their pathologic conditions can be visual-ized with proper equipment and technique.
Ultrasound equipment

Ultrasound units come in various sizes, whichrange from portable hand-held devices to moreconventional ultrasound units as seen in most hos-pitals or imaging centers. The most important con-sideration of any type of equipment is frequency ofthe transducer given in megahertz. The resolutionincreases as the frequency of the transducer in-creases, but this is at the expense of depth penetra-tion. To evaluate the shoulder or knee, typicallya 10 MHz or higher transducer is used, althoughlarger patients may require the use of a 7 MHz trans-ducer (Fig. 1). To evaluate the small nerve fasciclesof the distal extremities or the pulley system of thedigits, at least a 12 MHz transducer is optimal. In

Division of Musculoskeletal Radiology, Department of RCenter Drive, TC2910L, Ann Arbor, MI 48109-0326, USAE-mail address: [email protected]


skeletal imaging to avoid anisotropy, where a ten-don appears artifactually hypoechoic when notimaged perpendicular to the ultrasound beam [3].Curved transducers may be used to increase thefield of view when imaging larger body parts, suchas the hip and thigh. Smaller machines may nothave as many applications, such as power Dopplerimaging, but this varies between various ultrasoundmachines.

Scanning technique

First a transducer is selected that optimally balancesthe highest resolution and proper depth penetra-tion, which depends on the body part and structureto be imaged. For example, a 10 to 12 MHz trans-ducer may be used of most extremity applications,with lower frequency transducers considered forthe hip and other joints in a patient who has a largebody habitus, and higher frequency transducers forthe most distal extremities (see Fig. 1). The trans-ducer then is placed on the subject with ampleultrasound acoustic gel. It is optimal to hold thetransducer near the imaging surface while anchor-ing the transducer to the patient with the small fin-ger or the heel of the hand [4]. This will allow oneto make fine adjustments in transducer position,

adiology, University of Michigan, 1500 East Medical


mailto:[email protected]


Fig. 1. Transducer selection and image resolution. Ultrasound images longitudinal to the long head tendon ofbiceps brachii at 14 MHz (A) and 9 MHz (B). In this patient with a large body habitus, note improved resolutionof hyperechoic tendon fibers (arrows) and hypoechoic joint effusion (arrowhead) distending biceps tendonsheath with lower frequency transducer. Abbreviation: H, humerus.

Jacobson570

and control the amount of transducer pressureplaced on the patient. This technique is also helpfulto stabilize the transducer when imaging a curvedsurface or when performing dynamic imaging.The combination of transducer stabilization asdescribed previously and a thick layer of gel allowsone to float the transducer just above the skinsurface, which is helpful when evaluating for super-ficial abnormalities, such as foreign bodies. The re-sulting image then is optimized by adjusting thedepth of the image to bring the areas on interestinto view. If the ultrasound machine has adjustablefocal zones, these also should be moved to thedepth of interest to optimize resolution. The grayscale gain then is adjusted for brightness of theimage. When describing anatomic structures at ul-trasound, one refers to the imaging plane relativeto the structure itself, such as transverse and longi-tudinal, rather than the imaging plane relative tothe body.

Normal sonographic anatomy

An image is produced by a sound wave reflection,which depends on the acoustic impedance of the

Fig. 2. Normal flexor pollicis longus. Ultrasound images lolongus show normal hyperechoic fibrillar tendon (arrows

tissue and the angle of incidence. An interfacebetween tissues with large differences in acousticimpedance will reflect the sound wave, such asbetween soft tissues and bone. Similarly, a soundbeam that is perpendicular to the surface of anobject will produce a bright echo. The characteristicappearance of a structure at ultrasound is ap-preciated best when the structure is imaged perpen-dicular to the ultrasound beam. The ultrasoundappearance is described as hyperechoic (highecho), isoechoic (equal echo), hypoechoic (lowecho), or anechoic (no echo) relative to the adjacentsoft tissue structures. In addition, the sound beammay be brighter deep to a structure (called increasedthrough transmission) or may be absent deep toa structure (called shadowing). A repeated echodeep to a structure is called reverberation artifact[5]. A normal tendon appears hyperechoic with a fi-ber-like or fibrillar echotexture (Fig. 2) [6]. Normalmuscle tissue is predominately hypoechoic withinterspersed hyperechoic fibroadipose septationsor perimysium (Fig. 3A) [7]. These septationsconverge to an aponeurosis or tendon when themuscle is imaged longitudinally, while in the trans-verse plane, the septations produce a starry sky

ngitudinal (A) and transverse (B) to the flexor pollicis) surrounded by relatively hypoechoic muscle.

Fig. 3. Normal biceps brachii and brachialis. Ultrasound images longitudinal (A) and transverse (B) to the bicepsbrachii (Bi) and brachialis (Br) show hypoechoic muscle with interspersed hyperechoic fibroadipose septations(arrows), Abbreviations: H, humerus; arrowhead, dermis and epidermis.

Introduction to Musculoskeletal Ultrasound 571

appearance (Fig. 3B). Ligaments appear hypere-choic with an echotexture that is relatively morecompact when compared to tendon (Fig. 4), ex-tending from one bone attachment site to another[8]. Normal bone cortex reflects the ultrasoundbeam, which produces a very bright, smooth, andcontinuous echo (see Fig. 3). There is predomi-nantly shadowing deep to the bone, althoughreverberation also may be seen when imaged per-pendicular to the sound beam. Peripheral nerveshave a fascicular appearance when imaged longitu-dinally, where the individual nerve fascicles appearhypoechoic surrounded by hyperechoic connectivetissue (Fig. 5A) [2]. When imaged transversely,a peripheral nerve has a honeycomb appearance(Fig. 5B). Subcutaneous fat is hypoechoic but maybe more echogenic with increasing amounts offibrous tissue. The epidermis and dermis appear hy-perechoic (see Fig. 3A). Most bursae about the bodyare collapsed and difficult to identify at ultrasound.Some bursae may have a tiny amount of hypoechoic

Fig. 4. Normal anterior talofibular ligament. Ultra-sound image longitudinal to the anterior talofibularligament (arrows) shows normal compact hypere-choic appearance. Abbreviations: F, fibula; T, talus.

fluid, separating the adjacent hyperechoic bursalwalls. Although evaluation of cartilage is limiteddo to depth and location between articulating osse-ous structures, fibrocartilage appears hyperechoic(Fig. 6), and hyaline cartilage appears hypoechoic(Fig. 7) [9].

Artifacts

One must be aware of artifacts, as they can both as-sist in image interpretation and be a source of error.One of the most important of these artifacts isanisotropy, which can cause a normal tendon or lig-ament to appear abnormally hypoechoic, simulat-ing pathology (Figs. 8–10). The characteristicsonographic appearance of a tendon or ligamentis appreciated when the sound beam is perpendicu-lar to the axis of the structure being imaged. If thisangle of incidence is as little as 2� from perpendic-ular, the sound beam does not reflect back to thetransducer completely, and the tendon or ligamentwill appear artifactually isoechoic to muscle, andeventually hypoechoic when this angle reaches 7�

[3]. During real-time evaluation of a tendon or lig-ament, the transducer continually is being reposi-tioned or angled so that the area of concern isperpendicular to the sound beam. If a segment oftendon or ligament remained hypoechoic in spiteof transducer angling or repositioning, then pathol-ogy should be suspected. Anisotropy also can beused to one’s advantage. One example is when a ten-don is being imaged transversely and is surroundedby fat, such as in the ankle. In this situation, thehyperechoic tendon may be difficult to identifysurrounded by hyperechoic fat. By angling thetransducer along the long axis of the tendon, thetendon will become hypoechoic due to anisotropy,

Fig. 5. Normal median nerve at wrist. Ultrasound images longitudinal (A) and transverse (B) to the median nerveshow hypoechoic nerve fascicles (arrows) surrounded by hyperechoic connective tissue. Abbreviations: R, radius;L, lunate; t, flexor tendons.

Jacobson572

while the surrounding fat remains hyperechoic(Fig. 11). This maneuver also can help differentiatethe median nerve (which does not show anisot-ropy) from the adjacent flexor tendons in the wrist.Angling the transducer additionally will make anintratendinous hyperechoic calcification more con-spicuous when the surrounding tendon becomeshypoechoic from anisotropy.

In addition to shadowing deep to calcification orbone (see Fig. 3A) and reverberation artifact deepto a smooth flat surface (see Fig. 6), the soft tissuesdeep to a fluid collection or compact mass mayshow posteriorly through transmission [5]. Anotherartifact includes beam width artifact, where poste-rior shadowing or reverberation is not seen, becausethe structure being imaged is very small comparedwith the sound beam width [5]. One also may seeshadowing at the edge of a torn tendon, becauseof refraction shadowing [10].

Special ultrasound techniques

There are several more specialized technical optionson many ultrasound machines. One such technique

Fig. 6. Normal medial knee. Ultrasound image in thecoronal plane over medial knee shows hyperechoic fi-brocartilage meniscus (m), and compact hyperechoicsuperficial layer of the medial collateral ligament(arrows). Abbreviations: F, femur; T, tibial, arrow-head, reverberation artifact from bone cortex.

that is incorporated into many transducers is spatialcompounding. With this technique, the ultrasoundimage is produced from several different insonationangles [11]. Averaging images from these multipleinsonation angles improves tissue plane definitionand reduces speckle noise, but at the expense ofdecreased temporal resolution causing real-timemotion blur. Spatial compound imaging also maydecrease the echogenicity of structures such astendons, and the image may have a blurred ap-pearance, depending on the amount of spatialcompounding.

Another technique available on some ultrasoundmachines allows steering of the ultrasound beam.This may assist in reducing anisotropy when imag-ing a tendon that is coursing oblique relative to thesound beam. Angling the sound beam can decreasethis relative obliquity and decrease anisotropy.

Most ultrasound machines have color Dopplerimaging as an option, which displays blood flowas either red or blue if the flow is toward or awayfrom the transducer, respectively (Fig. 12A). PowerDoppler imaging is similar in that it also displaysblood flow, but the color display is independent

Fig. 7. Normal hyaline cartilage of knee. Transverseultrasound image over trochlea of distal femur (F)shows normal hypoechoic hyaline cartilage (arrows).

Fig. 8. Anisotropy of supraspinatus tendon. Ultrasound images longitudinal to the distal supraspinatus (S) showartifactual hypoechoic distal tendon (arrow) (A), which is no longer present when this segment of tendon isimaged perpendicular to sound beam (B). Abbreviations: D, deltoid muscle; H, humerus; arrowhead, subacro-mial-subdeltoid bursa.

Fig. 9. Anisotropy of subscapularis tendon. Ultrasound images longitudinal to the distal subscapularis (S) showartifactual hypoechoic distal tendon (arrow) (A), which is no longer present when this segment of tendon isimaged perpendicular to sound beam (B). Abbreviations: L, lesser tuberosity; arrowhead, long head of bicepsbrachii tendon in bicipital groove.

Fig. 10. Anisotropy of anterior talofibular ligament. Ultrasound images longitudinal to the anterior talofibularligament (arrows) show artifactual hypoechogenicity (A), which is no longer present when the ligament is im-aged perpendicular to sound beam (B). Abbreviations: F, fibula; T, talus.


Fig. 11. Anisotropy of ankle tendons. Ultrasound images transverse to tibialis posterior (t) and flexor digitorum(d) tendons show normal hyperechoic tendons (arrows) in (A), which become more conspicuous in (B) when thetransducer is angled along the longitudinal axis of the tendon, causing hypoechogenicity from anisotropy.

Jacobson574

of flow direction (Fig. 12B) [12]. Power Dopplerimaging is more sensitive compared with conven-tional color Doppler in demonstration of vascular-ity. The use of color and power Doppler imaging isimportant when differentiating between a solidmass and a cyst, as internal vascularity suggestssolid mass rather than cyst. In addition, color andpower Doppler imaging is used to detect synovitisand to determine the activity of the synovitis [13].It is important to understand that increased flowon color or power Doppler imaging does not alwaysindicate inflammation. Increased flow also may beseen with neovascularity related to tendinopathyor tumor.

Ultrasound machines also may have the optionof extended field-of-view. With this option, thetransducer is moved across an extremity, and theimage data are summated to produce the extendedfield-of-view image (Fig. 13). This technique ishelpful when measuring pathology that is largerthan the transducer [14]. Such situations includemeasurement of large tumors or measuring theamount of tendon retraction in the setting ofa full-thickness tear.

Fig. 12. Color and power Doppler imaging. Transverse im(A) and power Doppler (B) imaging shows blood flow. N

One additional option with some ultrasoundmachines is tissue harmonic imaging. With thistechnique, harmonic frequencies are used to pro-duce the ultrasound image [15]. Because theseharmonic frequencies are amplified rather than at-tenuated, penetration is improved; contrast resolu-tion is increased, and artifacts such as side-lobe andreverberation are reduced [16]. Tissue harmonicimaging may improve visibility of structures, espe-cially deeper structures such as the subscapularisin the shoulder.

Musculoskeletal applications

The most common application in musculoskeletalultrasound is evaluation of tendon and muscle ab-normalities. Ultrasound is effective in showing nor-mal tendon, diagnosing tendinosis and tendon tear,and diagnosing muscle tears [9]. Calcific tendinitisalso is demonstrated effectively with ultrasound,and ultrasound can be used to guide percutaneousaspiration of the calcification [17]. The rotatorcuff is the most common site of tendon evaluationwith ultrasound.

aging of the posterior tibial artery (arrow) with colorote adjacent veins.

Fig. 13. Extended field-of-view imaging. Longitudinalimaging of the forearm with extended field-of-viewshows the brachioradialis muscle (arrows). H,humerus.


Another common application is the evaluationfor soft tissue infection, such as abscess and celluli-tis, and to diagnose joint effusions [18]. Ultrasoundalso may be used to percutaneously guide aspira-tion of any suspected abscess or infected jointeffusion. In the setting of rheumatoid arthritis,ultrasound may detect and quantify synovitis [19].

Because the resolution of ultrasound is greaterthan routine MR imaging, ultrasound is beingused to evaluate peripheral nerves for entrapmentdisorders, nerve trauma, and peripheral nervesheath tumors [20]. An entire extremity can be eval-uated in less time than what it would take with MRimaging, and direct correlation with symptoms andcontralateral comparison are both possible with ul-trasound. Dynamic imaging effectively diagnosesulnar nerve dislocation at the elbow, and relatedsnapping triceps syndrome [21].

The most common ligaments evaluated with ul-trasound are the ulnar collateral ligament of thefirst metacarpophalangeal joint for Gamekeeper’sthumb [22] and the ulnar collateral ligament ofthe elbow. In this latter situation, dynamic imagingcan evaluate for joint space widening during valgusstress across the elbow joint [23].

There are many other miscellaneous conditionsevaluated with ultrasound, such as bursitis, frac-tures, cysts, and masses. Dynamic imaging is helpfulfor diagnosing muscle hernias, often only presentduring muscle contraction [24]. The high-resolutioncapabilities of ultrasound also make it successful inthe evaluation of soft tissue foreign bodies.

Summary

The first step in effective use of musculoskeletal ul-trasound is proper transducer selection and techni-cal adjustments to optimize resolution. Scanningtechnique is also important so that small structuresand subtle pathology can be recognized. Normalstructures have characteristic appearances at ultra-sound. Knowledge of common ultrasound artifactshelps to identify many pathologic conditions.Specialized ultrasound techniques, such as beamsteering, extended field-of-view, color and powerDoppler imaging, and harmonic imaging can assist

diagnosing and characterizing many pathologicconditions.

References

[1] Mayer V. Ultrasonography of the rotator cuff.J Ultrasound Med 1985;4:608.

[2] Silvestri E, Martinoli C, Derchi LE, et al. Echotex-ture of peripheral nerves: correlation between USand histologic findings and criteria to differentiatetendons. Radiology 1995;197:291.

[3] Crass JR, van de Vegte GL, Harkavy LA. Tendonechogenicity: ex vivo study. Radiology 1988;167:499.

[4] Jacobson JA. Fundamentals of musculoskeletalultrasound. 1st edition. Philadelphia: SaundersElsevier; 2007.

[5] Scanlan KA. Sonographic artifacts and theirorigins. AJR Am J Roentgenol 1991;156:1267.

[6] Martinoli C, Derchi LE, Pastorino C, et al. Analysisof echotexture of tendons with US. Radiology1993;186:839.

[7] Peetrons P. Ultrasound of muscles. Eur Radiol2002;12:35.

[8] Erickson SJ. High-resolution imaging of the mus-culoskeletal system. Radiology 1997;205:593.

[9] Jacobson JA, van Holsbeeck MT. Musculoskeletalultrasonography. Orthop Clin North Am 1998;29:135.

[10] Hartgerink P, Fessell DP, Jacobson JA, et al. Full-versus partial-thickness Achilles tendon tears:sonographic accuracy and characterization in26 cases with surgical correlation. Radiology2001;220:406.

[11] Lin DC, Nazarian LN, O’Kane PL, et al. Advan-tages of real-time spatial compound sonographyof the musculoskeletal system versus conven-tional sonography. AJR Am J Roentgenol 2002;179:1629.

[12] Bude RO, Rubin JM. Power Doppler sonography.Radiology 1996;200:21.

[13] Newman JS, Adler RS, Bude RO, et al. Detection ofsoft-tissue hyperemia: value of power Doppler so-nography. AJR Am J Roentgenol 1994;163:385.

[14] Lin EC, Middleton WD, Teefey SA. Extendedfield-of-view sonography in musculoskeletalimaging. J Ultrasound Med 1999;18:147.

[15] Rosenthal SJ, Jones PH, Wetzel LH. Phase inver-sion tissue harmonic sonographic imaging:a clinical utility study. AJR Am J Roentgenol2001;176:1393.

[16] Strobel K, Zanetti M, Nagy L, et al. Suspectedrotator cuff lesions: tissue harmonic imaging ver-sus conventional US of the shoulder. Radiology2004;230:243.

[17] del Cura JL, Torre I, Zabala R, et al. Sonographi-cally guided percutaneous needle lavage incalcific tendinitis of the shoulder: short- andlong-term results. AJR Am J Roentgenol 2007;189:W128.

[18] Bureau NJ, Chhem RK, Cardinal E. Musculoskel-etal infections: US manifestations. Radiographics1999;19:1585.

Jacobson576

[19] McNally EG. Ultrasound of the small joints ofthe hands and feet: current status. Skeletal Radiol2008;37:99.

[20] Martinoli C, Bianchi S, Derchi LE. Ultrasonogra-phy of peripheral nerves. Semin Ultrasound CTMR 2000;21:205.

[21] Jacobson JA, Jebson PJ, Jeffers AW, et al. Ulnarnerve dislocation and snapping triceps syn-drome: diagnosis with dynamic sonography—re-port of three cases. Radiology 2001;220:601.

[22] Ebrahim FS, De Maeseneer M, Jager T, et al. US diag-nosis of UCL tears of the thumb and Stener lesions:technique, pattern-based approach, and differentialdiagnosis. Radiographics 2006;26:1007.

[23] De Smet AA, Winter TC, Best TM, et al. Dynamicsonography with valgus stress to assess elbowulnar collateral ligament injury in baseballpitchers. Skeletal Radiol 2002;31:671.

[24] Beggs I. Sonography of muscle hernias. AJR Am JRoentgenol 2003;180:395.



577

Common Tendon and MuscleInjuries: Upper ExtremitiesKaren Finlay, MDa,b,*, Lawrence Friedman, MB, BChc

- ShoulderRotator cuffBiceps tendonPectoralisDeltoid

- Arm- Elbow

Distal biceps tendonCommon extensor tendonCommon flexor tendon

Distal triceps tendon- Forearm- Wrist

Extensor compartmentsFlexor compartment

- HandExtensor mechanismFlexor mechanism

- Summary- References

Soft tissue injuries of the upper extremity are abnormalities to clinical colleagues. Extended field
a common presentation in clinical practice and in-clude acute traumatic injuries and chronic overusesyndromes. There are certain advantages of ultraso-nography for assessment of these injuries, includingreal-time imaging assessment, multiplanar capabil-ity, and the ability to palpate, compress, and easilycompare with the contralateral side. The opportu-nity to physically examine the patient facilitatescorrelation of imaging findings with patient symp-toms. With the development of extended field-of-view imaging, ultrasound is now capable ofimaging and documenting upper extremity pathol-ogies that extend beyond the traditional small fieldof view of standard ultrasound probes. Thisextended field of view assists in illustrating relation-ships to important regional anatomic landmarks,enhances measurement, and aids in demonstrating
a Department of Diagnostic Imaging, Henderson HospitEast, Hamilton, Ontario L8V 1C3, Canadab Department of Radiology, McMaster University, 12003Z5, Canadac Department of Diagnostic Imaging, North York Genera1E1, Canada* Corresponding author. Department of Diagnostic Imag711 Concession Street East, Hamilton, Ontario L8V 1C3,E-mail address: [email protected] (K. Finlay).


of view imaging can also prove extremely helpful,particularly in the setting of muscle and tendon in-juries, in documenting the relationships amongtendon, muscle, and musculotendinous junction.

The purpose of this article is to review the sono-graphic appearance of a variety of common injuriesinvolving the muscles and tendons of the upperextremity. Injuries affecting the shoulder, elbow,and wrist joint regions and muscle and tendoninjuries affecting the arm and hand are included.Various disorders are discussed and illustrated.

Shoulder

Rotator cuff

Rotator pathology is a common source of shoulderpain. Tendon pathology ranges from tendinosis to

al, Hamilton Health Sciences, 711 Concession Street

Main Street West, Box 2000, Hamilton, Ontario L8N

l Hospital, 4001 Leslie Street, Toronto, Ontario M2K

ing, Henderson Hospital, Hamilton Health Sciences,Canada.




Finlay & Friedman578

partial- and full-thickness tears. Tendinosis or ten-dinopathy of the rotator cuff tendons presentswith an abnormal appearance to the tendon onultrasound, including tendon thickening, loss ofthe normal organized fibrillar echotexture of thetendon, and areas of hypoechoic change (Fig. 1).These findings may be focal or diffuse. It is impor-tant to ensure that the areas of hypoechoic changeare not mimicked by anisotropy, a common artifactencountered in musculoskeletal ultrasound appli-cations. Comparison with the asymptomatic shoul-der can be useful to appreciate subtle alterations intendon appearance, particularly for beginnerscanners. A tendon thickness greater than 8 mmhas been described as an indicator of tendinopathy;however, tendinosis can be present without associ-ated tendon thickening [1].

Although tears of the rotator cuff are most com-monly seen in the elderly population, they arealso encountered in young athletes who participatein sporting activities requiring overhead arm move-ments. Tears are classified as partial thickness or fullthickness. Partial tears include three subtypes:bursal-sided, articular-sided, and intrasubstance.Cadaveric studies have documented partial-thick-ness tears as more frequent than their full-thicknesscounterpart, and partial-thickness tears are morefrequently documented in younger populationsthan full-thickness tears [2,3]. It is important toattempt to identify a partial-thickness tear on short-and long-axis views of the tendon to avoid confus-ing the appearance of tendinosis or anisotropymimicking a tear. The size of the tear should becarefully measured in the two planes. In addition,the percentage of tendon thickness involvementcan be estimated, to assist in best representing the

Fig. 1. Supraspinatus tendinosis. (A) Longitudinal image oinsertion onto the greater tuberosity (GT) demonstrates aappearance (arrows), consistent with tendinopathy. (B) S(arrows).

extent of tendon involvement for clinical col-leagues. Classification systems for describingpartial-thickness tears have been developed,including one by Ellman [4]. This system includeslocation description (articular, bursal, interstitial)and depth (grade 1, <3 mm; grade 2, 3–6 mm;grade 3, >6 mm). Measurements are important be-cause the degree of tendon involvement hasimplications for surgical management [5]. Mostpartial-thickness rotator cuff tears are diagnosedin the supraspinatus tendon [2]. Clinical studieshave shown that articular-sided partial-thicknesstears are more common than bursal-sided [6,7]and appear as hypoechoic or anechoic areas involv-ing the deep articular side of the tendon (Fig. 2).There may or may not be a visible cartilage interfacesign [8]. Bursal-sided tears result in a focal area ofdisruption involving the smooth superior surfaceof the tendon. The defect created by the bursal-sided tear often fills with fluid, which can assist inits identification (Fig. 3). When the defect fillswith synovium, it can be more challenging to iden-tify. Intrasubstance or interstitial tears present onultrasound as discrete anechoic areas within thesubstance of the tendon, without communicationto the articular or bursal side of the tendon(Fig. 4). These tears may be linear and delaminatebetween muscle fibers or may be focal and morevolumetric. A variant partial-thickness articulartear occurs at the footprint of the supraspinatustendon, at the fibrocartilaginous insertion ontothe greater tuberosity facet, sometimes referred toas a rim rent tear. These small tears, often seen inyounger individuals, are avulsion-type minutetendon tears that are often identified at the junctionof the anatomic neck of the humerus, close to the

f the distal supraspinatus tendon (SS) near the level offocal area of hypoechoic change and loss of fibrillar

imilar change is demonstrated on the short-axis view

Fig. 2. Partial-thickness articular-sided tear. (A) Longitudinal image of the distal supraspinatus tendon (SS)demonstrates an anechoic area of fluid involving the deep articular side of the tendon (arrow). The underlyingcartilage surface is visible as a thin hyperechoic line (arrowheads). (B) The same finding is demonstrated on theshort-axis view.

Tendon and Muscle Injuries: Upper 579

biceps tendon. A focal linear or hyperechoic areamay be identified centrally, surrounded by hypoe-choic tendon edema or anechoic fluid (Fig. 5) [9].This tear is often associated with underlying corticalirregularity of the greater tuberosity.

Full-thickness tears, by definition, extend fromthe articular to the bursal side of the tendon. Thesetears may involve the entire tendon (full width) oronly part of the tendon (partial width). The

Fig. 3. Partial-thickness bursal-sided tear. (A) Longitudinafootprint insertion on greater tuberosity (GT) shows a foof the tendon (straight arrow), consistent with a partial-toverlying subdeltoid bursa (curved arrow). (B) Short-axis viintact deeper fibers closer to the articular side of the ten

dimensions of the tear are important to measurein both planes to provide the referring clinician orsurgeon with adequate information for evaluatingthe extent of tear, for treatment consideration, orneed for further imaging. The transverse- or short-axis image determines the width of the tendon in-volved; the longitudinal axis determines the extentof tendon retraction (Fig. 6). The most commonsite of full-thickness tear is the anterior portion of

l image of the distal supraspinatus tendon (SS) nearcal cleft or anechoic area involving the bursal surfacehickness tear. The tear is contiguous with fluid in theew also demonstrates the tear (arrow), along with thedon (arrowheads).

Fig. 4. Intrasubstance tear. (A) Longitudinal image of the distal supraspinatus tendon (SS) illustrating a fluid-filled cleft within the substance of the tendon (arrows), which does not communicate to the articular or bursalsurface. GT, greater tuberosity. (B) The short-axis view demonstrates some overlying tendon fibers on the bursalsurface (arrowheads) overlying the intrasubstance tear (arrows).


the supraspinatus, at the critical zone. Typically,full-thickness tears are easier to detect thanpartial-thickness tears. When full-thickness tearsare small or the tendon tear delaminates throughthe tendon, these tears can prove more difficult todiscriminate from a partial-thickness tear. Whentears are acute, fluid outlines the area of tendondefect. In the chronic setting, the appearance canbe confusing because thickened bursa may fill thegap, mimicking a normal tendon. In this instance,the use of graded compression assists in identifyingthe absent tendon. Tears immediately adjacentto the biceps interval can also be challenging to

Fig. 5. Partial-thickness tear at level of supraspinatustendon (SS) at tendon footprint insertion onto thegreater tuberosity (GT) is identified on this longitudi-nal image as a deep anechoic area in the tendon(arrowheads) surrounding a small linear hyperechoicline (arrow), sometimes referred to as a rim rent tear.

identify. To avoid this pitfall, it is important toobserve the width of the biceps interval, evaluatefor abnormal fluid or apparent widening, and inter-rogate the very medial edge of the supraspinatustendon. In the setting of acute full-thickness rotatorcuff tears, the proximal tendon stump is typicallyless retracted and can be visualized by ultrasound[7]. With more chronic tears, the tendon stumpfrequently retracts under the acromion and ismore difficult to identify.

All rotator cuff tendons should be evaluated todetermine the extent of rotator cuff involvement.Often, infraspinatus involvement is present withposterior extension of a supraspinatus tear. Isolatedinfraspinatus tendon tears may be encountered asan injury in overhead athletes. Subscapularis tearscan also present as an isolated finding, often relatedto traumatic injury such as a fall with the armabducted and externally rotated [7,10]. Given thebroad insertion of this tendon in its cranial caudalorientation, it is important to evaluate the superiorand the inferior subscapularis fibers. This evalua-tion is best achieved with careful technique, includ-ing evaluation in the sagittal plane, assessing theshort-axis appearance of the tendon fibers. Associ-ated fatty infiltration or atrophy changes havebeen described on ultrasound (Fig. 7) [11]. Thisfinding is better delineated with MR imaging.

Biceps tendon

Isolated tears of the long head biceps brachii ten-don are rare because they more commonly presentin the setting of a rotator cuff tear [12,13]. Tearsmay be due to degeneration or attrition, frequentlyseen in the elderly population. They may also occur

Fig. 6. Full-thickness tear. (A) Longitudinal image of the supraspinatus demonstrates absence of the normaltendon, with proximal retracted tendon stump (asterisk). The full-thickness tendon defect is filled with fluid,delineating the extent of resultant tear (arrows). GT, greater tuberosity. (B) The corresponding transverse imagedemonstrates the tear commencing at the leading edge of the tendon, adjacent to biceps tendon (BT), withtransverse or anteroposterior extent indicated with arrows.


as a result of acute trauma from a direct blow or fallon outstretched hand, which is more common inyounger patients. Longstanding tears of the longhead biceps tendon present with a classic clinicalfinding of Popeye sign (Fig. 8). This clinical findingis due to abnormal bulging contour of the bicepsbrachii muscle, exaggerated with flexion against re-sistance. It is important not to be misled by the ab-sence of this sign due to swelling and hematoma inthe setting of acute trauma [12]. Full-thickness longhead biceps tendon tears are identified by the ab-sence of the normal fibrillar tendon fibers in thetendon sheath. In acute tendon tears, the synovialtendon sheath fills with fluid and the retracted ten-don stump can be identified lying within the sheath

(Fig. 9) [14]. With tendon rupture, the myotendi-nous junction or distal tendon stump typically mi-grates distally and can be identified below the levelof the pectoralis insertion on the humerus, whichserves as a useful landmark [7]. When acute, themyotendinous junction is usually surrounded bysome fluid. Given the association with rotator cuffinjury, it is important to also interrogate the rotatorcuff tendons for additional sites of soft tissue injury.Ultrasound is more limited in the diagnosis of par-tial-thickness biceps tendon tears because extensivepartial-thickness tears may be diagnosed as full-thickness, and less-extensive partial-thickness tearsmay be missed, as are intracapsular tears [15]. Inthe setting of a partial tear, the tendon often appears

Fig. 7. Supraspinatus fatty atrophy.Images of the posterior shoulderobtained in the transverse planedemonstrate the normal ultrasoundappearance of the supraspinatusmuscle on the left (LT) shoulder(straight arrows). Compare with theabnormal increased muscle echotex-ture in the right (RT) supraspinatusmuscle (curved arrows) in the samepatient. This finding was present inthe setting of a full-thickness rotatorcuff tear. Scap, scapula.

Fig. 8. Popeye sign. In a patient who has rupture ofthe long head biceps brachii tendon, the inferiorlypositioned muscle belly appears as a rounded bulgein the lower anterior arm (arrows) when the arm isflexed against resistance.

Fig. 10. Long head biceps tendon tear. Proximal trans-verse image at the level of the biceps groove (BG)demonstrates absence of the normal round tendon(arrows) in the setting of previous tendon rupture.


larger and more hypoechoic [16]. The most com-mon ultrasound finding for full-thickness tear ofthe long head biceps tendon is nonvisualizationof the tendon in the superior aspect of the intertu-bercular groove, also known as an empty bicepsgroove sign (Fig. 10).

It is important to recognize that fluid in thebiceps tendon sheath is nonspecific: it can be seenin the setting of multiple biceps tendon pathologiesincluding tears, tendinopathy, tenosynovitis, rota-tor cuff disease, or any other cause for glenohum-eral joint effusion. Given this, diagnosis ofabnormalities related to the biceps tendon in thissetting should be regarded with caution unless

Fig. 9. Long head biceps tendon rupture. Transverseimage of a torn right (RT) long head of biceps tendon(LH B) demonstrates abnormal fluid (arrows) sur-rounding the retracted tendon stump (asterisk). Thetendon stump is positioned adjacent to the shorthead biceps muscle belly (SH B).

there are other signs of biceps tendon pathologysuch as loss of normal fibrillar architecture, fiberdisruption, tendon enlargement, or synovial prolif-eration. Rupture of the short head of the bicepstendon is extremely rare, as are tears of the coraco-brachialis [12].

Ultrasound is accurate in the diagnosis of bicepssubluxation and dislocation [15]. With subluxationor dislocation, the long head biceps tendon almostalways moves medially (Fig. 11), which is oftenassociated with subscapularis tendon tears or injuryto the biceps pulley mechanism. In these instances,the tendon may be identified deep to the torn sub-scapularis and may even become deeply positionednear the anterior glenohumeral joint margin. It isimportant to identify a dislocated tendon to avoid

Fig. 11. Biceps tendon subluxation. Transverse imageat the level of the proximal biceps groove (arrow-heads) demonstrates subluxation of the bicepstendon (arrows) positioned over the apex of thelesser tuberosity (LT). GT, greater tuberosity.


falsely diagnosing a torn long head biceps tendonwhen normal tendon is not identified proximallyin the biceps tendon groove. Dislocations can occuras a transient or intermittent phenomenon, whichcan be identified with dynamic scanning on inter-nal and external rotation, with the ultrasoundprobe in the short axis or transverse orientationrelative to the tendon [17].

Pectoralis

Traumatic injuries to the pectoralis tendon areuncommon and can occur from indirect trauma(most common) or direct trauma (less common)[12,18]. These injuries are usually diagnosed inmale athletes or weight lifters aged 20 to 40 years.Injury is usually incurred as an indirect force suchas a sudden overload of weight causing excessivemuscle tension. This indirect force results inavulsion injuries from the humerus site of tendoninsertion or at the musculotendinous junction.Pectoralis injury can also occur with direct trauma,and these tears can be seen in the muscle belly [18].Tears have also been reported in the elderlypopulation, occurring during patient positioningor transfer [19].

Patients who have pectoralis tears usually reporta sudden ‘‘pop’’ or ‘‘tear’’ sensation, followed bypain and subsequent bruising involving the ante-rior chest wall or breast (if tear is in the musclebelly) or involving the medial arm, lateral chestwall, or axilla (if the tear is more distal). Clinically,there may be loss of the normal anterior axillaryfold, with a visible and palpable defect (Fig. 12).On clinical examination, it is often difficult todetermine the extent of injury [20]. The site andextent of injury are important to identify becausethey have surgical implications [12,20]. Partial tearsor findings in sedentary patients may be treated

Fig. 12. Pectoralis tear. Normal anterior axillary fold appshoulder demonstrates the loss of normal fold (arrow) andheads) in the setting of pectoralis tear.

conservatively, whereas surgical treatment is usuallyfavored for full-thickness injuries [12,21]. Ultra-sound has been described as a useful tool for imag-ing and evaluating the location and extent of thisinjury (Fig. 13) [21]. Flexion and relaxation tech-niques and the ABER (shoulder abduction, externalrotation) position may be helpful when the patientis able to cooperate with this position, becausethe myotendinous junction is stressed with thismaneuver (Fig. 14) [21].

Deltoid

The deltoid muscle is a large multipennate musclethat forms the characteristic round contour of theshoulder. Proximally, the muscle has attachmentsto the distal clavicle, acromion, and spine of thescapula and inserts onto the deltoid tuberosity ofthe humerus. Deltoid muscle injuries are rare,with most cases identified in the setting of extensiverotator cuff tears, with spontaneous rupture morecommon than traumatic rupture (Fig. 15) [22].The tear results in loss of the normal round contourof the shoulder, with the defect often palpable.

Arm

The arm contains important proximal muscles thatact on the shoulder and elbow joint. Knowledge ofthe flexor and extensor muscle groups of the arm isimportant for the assessment of local pathologyand for tracing pathology proximal and distal tothe more commonly imaged shoulder and elbowjoints. The anterior compartment consists of thebiceps brachii, coracobrachialis, and brachialismuscles; the posterior compartment consists ofthe triceps muscle.

Injury to the muscles of the arm can occur withblunt or penetrating trauma. Trauma to muscles

earance is demonstrated on the right shoulder. Leftabnormal shallow indentation or skin crease (arrow-

Fig. 13. Pectoralis tear. Extended field-of-view long-axis image demonstrates a tear in the pectoralismajor (Pect Major) (arrows) at the level of the myo-tendinous junction. LT, left.


results in disruption of the organized pennate orherringbone pattern commonly recognized onultrasound (Fig. 16). Muscle tears can appear ashypoechoic areas with loss of normal echogenicepimysium. Larger areas of muscle injury presentwith fluid-containing regions of hematoma orseroma, with surrounding frayed muscle ends.Hematoma can dissect between muscle groups. Itis important to also evaluate the regional neurovas-cular structures when assessing patients who havemuscle trauma (see Fig. 16B).

Sequelae of muscle tears include anechoic fluidcollections or cysts, scarring, and myositis ossifi-cans. Myositis ossificans is a post-traumatic self-

Fig. 14. Pectoralis tear dynamic imaging. Images orientedmyotendinous junction demonstrate a small cleft of fluidand determine extent of thickness with tension on the m

limiting condition that usually involves large mus-cles and is often seen in athletes who play contactsports. In the upper extremity, it most frequently in-volves the arm. Findings can be identified on ultra-sound and plain films. On ultrasound, initialfindings can be identified within 3 weeks post in-jury. An ovoid hypoechoic soft tissue lesion witha more hyperechoic center (ultrasound featuresconsistent with zonal phenomenon) begins to de-velop a hyperechoic rim as a result of early ossifica-tion [23]. When calcifications first appear, they maybe seen earlier by ultrasound than on plain films[24]. Early calcification is followed by more orga-nized peripheral calcification, with the course of le-sion maturity taking 5 to 6 months [24]. When theperipheral calcification is mature, ultrasound dem-onstrates acoustic shadowing, reflecting the charac-teristic plain film finding (Fig. 17). To avoidmisdiagnosing other, more aggressive etiologies inthis instance, it is always important to correlatethe ultrasound appearance with plain films andpossibly CT to confirm peripheral zonalcalcification.

Elbow

Distal biceps tendon

Distal biceps brachii tendon rupture is an infre-quent injury of the upper extremity, commonlyincurred with forced extension against an elbowin midflexion, such as when lifting a heavy object

along the long axis of the muscle at the level of the(left image arrow), which is much easier to identify

uscle (right image arrow).

Fig. 15. Deltoid muscle tear. (A) Longitudinal image of the deltoid muscle identifies a large tear in the deltoidmuscle (arrows), with central hematoma (asterisk). (B) Transverse image at same level clearly demonstratesa fluid/fluid level (arrowheads) within the central hematoma (arrows) in this acute tear.


or weight lifting. Often, the patient recalls a suddenpop or tearing sensation and acute onset of pain.The finding is diagnosed clinically with a palpableand occasionally visible defect in the antecubitalfossa, appreciated as loss of the normal ropeliketendon crossing the anterior elbow crease(Fig. 18). If the rupture is acute, bruising may beevident in the region. Patients have difficulty withflexion and supination. When proximally retractedabove the elbow joint, the retracted tendon maybe palpated as a mass. Clinically, this diagnosiscan be more challenging in the setting of nonre-tracted tendon tears, for which imaging is useful.Ultrasound has been shown to be a useful tool for

Fig. 16. Penetrating injury to biceps brachii (Biceps Br). (Aceps brachii, performed to assess injury following a stab wwith loss of the normal striate muscle appearance (arrowmatic muscle tear (asterisk) demonstrates partial-thicknessof the median nerve (Med N) (arrowheads).

this diagnosis because it is targeted, quick, andeconomical [25]. Ultrasound findings of distalbiceps tendon rupture include nonvisualization ofthe distal tendon coursing to the radial tuberosity,fluid or complex mass in the antecubital fossaregion, and fluid around the proximal tendonstump (Fig. 19). Longitudinal images are helpfulfor identifying the location of the proximal tendonstump [26]. The degree of tendon retraction fromthe distal insertion site can be directly measured.Retracted tears are easier to diagnose than nonre-tracted or partial-thickness tendon tears [25,27].Occasionally, tears may occur at the myotendinousjunction (Fig. 20).

) Extended field-of-view longitudinal image of the bi-ound, identifies a large area of muscle injury (asterisk)s). (B) Transverse image at medial margin of the trau-injury (curved arrow) involving the superficial surface

Fig. 17. Myositis ossificans. (A) Longitudinal image of the biceps brachii (Biceps Br) muscle identifies a hypere-choic soft tissue process (arrowheads) associated with posterior acoustic shadowing (arrow) in a patient whohad previous blunt trauma. (B) Axial view of the shoulder demonstrates faint soft tissue calcification anteriorly(arrow).


Common extensor tendon

The normal common extensor tendon on ultra-sound appears as a compact linear structure arisingfrom the lateral humeral epicondyle. In the settingof epicondylitis, tendon changes include a thick-ened and heterogeneous appearance, with loss ofthe normal tendon fibrillar echotexture. Thesetendon changes may be focal or diffuse. This condi-tion is commonly known as ‘‘tennis elbow’’ and isthought to be secondary to a repetitive stress-typeinjury. There may or may not be calcificationspresent in chronic tendinopathy (Fig. 21). Addi-tional insertional changes include underlying

Fig. 18. Distal biceps tendon rupture. Right elbowdemonstrates loss of the normal anteromedial softtissue contour (arrows) associated with distal bicepstendon tear. Compare with normal appearance ofthe left antecubital fossa.

bone irregularity or spurring. There may be a generalprogression to tendon degeneration and tearswithin the tendon. Partial-thickness tears appearas hypoechoic or anechoic regions; complete-thick-ness defects represent full-thickness tears. Imagingis valuable in the setting of pain that is not self-lim-iting or does not respond to usually conservativetherapy, particularly when the individual is consid-ered a surgical candidate. In these instances,ultrasound can prove valuable for confirmingdiagnosis and assessing severity and extent of

Fig. 19. Tear distal right (RT) biceps tendon. Longitu-dinal image of the anterior elbow identifies ruptureof the biceps tendon (BT), with absence of the distaltendon fibers extending to the level of the radial tu-berosity insertion. Fluid fills the normal expectedcourse of the tendon (arrowheads). The arrows indi-cate the extent of tendon retraction (left side of im-age is distal).

Fig. 20. Proximal tear distal biceps brachii (Biceps Br) tendon. Longitudinal image of the biceps tendon at thelevel of the distal myotendinous junction identifies a tear (asterisk). This tear is associated with a small calcifi-cation (arrow). Intact tendon fibers are identified distal to the site of tear (arrowheads) (right side of imageis distal).


involvement [28]. Deep tendon fiber injury isreportedly more common than intermediate orsuperficial fiber involvement (Fig. 22) [28].

Common flexor tendon

The normal common flexor tendon appears as a hy-perechoic ‘‘beaklike’’ or triangular structure, dem-onstrating the typical fibrillar echotexture oftendons. The medial flexor tendon has a broaderorigin than its extensor or lateral counterpart.

Fig. 21. Lateral epicondylitis. Longitudinal image atthe level of the common extensor tendon (CET) at lat-eral (Lat) epicondyle illustrates abnormal thickeningand central hypoechoic change within the substanceof the tendon (arrowheads). This area of abnormalechotexture is associated with some small calcifica-tions (arrow) (right side of image is distal).

Tendinopathy or epicondylitis changes mediallyare commonly referred to as ‘‘golfer’s elbow.’’ Inthis situation, the tendon is variably thickened,heterogeneous, or hypoechoic. Appearances aresimilar to the common extensor tendon, in thatthere may be underlying bony irregularity on themedial humeral epicondyle, and tendon calcifica-tions in longstanding disease. Tears may occur asa chronic phenomenon or secondary to a traumaticevent.

Fig. 22. Partial-thickness tear common extensor ten-don. Longitudinal image of the common extensortendon (CET) identifies a tear (arrowheads) involvingthe deep fibers, with overlying intact superficialfibers. Findings are consistent with a partial-thicknesstear (right side of image is distal). Lat, lateral.


Distal triceps tendon

Triceps brachii tendon injuries are uncommon[29]. There may or may not be an associated avul-sion injury of the olecranon process. Sonographicfindings for distal triceps tendon tear includenonvisualization of the normal tendon fibrillarechotexture at the level of the olecranon process,an area of fluid filling the tendon gap, and a proxi-mal retracted tendon stump (Fig. 23). Degree oftendon retraction is best assessed and measuredon longitudinal imaging. Tears may be partial thick-ness or full thickness. When the tendon stumps areclosely approximated or there is debate over partial-versus full-thickness defect, dynamic scanning withflexion and extension is useful. Because the

Fig. 23. Distal triceps tendon tear. (A) Longitudinalimage of the distal triceps tendon demonstratesa full-thickness tear of the triceps tendon, with fluidfilling the gap of the normal course of the tendon(arrows). Proximally, an ossified fragment is present(arrowheads). (B) Corresponding lateral radiographyconfirming the proximal fragment at level ofretracted tendon stump (arrow).

diagnosis is often clinically evident, the role of ul-trasound in this diagnosis is to determine the extentof tendon tear and degree of retraction.

Forearm

The muscles of the forearm are separated into ante-rior (flexor) and posterior (extensor) compart-ments. The proximal and lateral compartment,also known as the mobile wad, includes the bra-chioradialis and extensors carpi radialis longusand brevis. With the exception of sequelae frompenetrating injuries or secondary abnormalitiesdue to blunt trauma, injuries of the forearmmuscles and tendons are extremely uncommon.General principles for evaluation of partial- orfull-thickness injuries apply.

Wrist

The flexor and extensor muscle and tendon groupshave unique anatomic relationships at the wrist,aiding in their recognition. The wrist tendons areprone to overuse or repetitive stress disordersfrom occupational or sporting activities and frominflammatory and infectious conditions. The mostfrequent wrist tendon pathology is overuse injury.Tenosynovitis of the wrist presents with variableamounts of fluid or synovitis distending the syno-vial sheath, with possible hypoechoic or heteroge-neous tendon thickening. Increased synovialsheath fluid is also frequently present in the settingof acute partial- or full-thickness tendon tears; how-ever, when tears are chronic, this fluid may resorband tendon ends retract [30]. It is important atthe time of scanning to assess and measure thegap created by the retracted tendon ends in addi-tion to useful anatomic landmarks to provide keyinformation for the hand surgeon.

Extensor compartments

The extensor group is separated into six separatecompartments at the level of the wrist by the exten-sor retinaculum, numbered from radial to ulnarside. Each compartment is lined with synovium tofacilitate smooth tendon action. Knowledge ofeach of these tendons is important for correct iden-tification in the setting of injury or abnormality.

Tenosynovitis of the extensor compartments iscommon. The most common repetitive or overusesyndrome affecting the extensor compartments isan inflammatory compartment 1 disorder com-monly known as de Quervain’s disease. This disor-der of the abductor pollicis longus and extensorpollicis brevis common tendon sheath is oftenseen in athletes, laborers, caregivers of babies, andhousekeepers. Patients present with pain localized


to the radial styloid, and there is often palpable softtissue fullness at the same level. The diagnosis iseasily made on ultrasound. In acute presentations,variable amounts of peritendinous fluid and ten-don thickening are present, usually maximal atthe level of the radial styloid (Fig. 24). Chronicfeatures include synovial thickening, retinaculumthickening, and occasional nodule formation [31].Transverse images of the area are often the mostuseful for identifying these changes; comparisonwith the contralateral wrist is helpful for appreciat-ing subtle disease.

Variable pathologies affect the other extensorcompartments. Tendinosis and tenosynovitis inany of the extensor compartments predisposes tofurther tendon injury (Fig. 25). The second com-partment tendons—extensor carpi radialis longusand brevis—may be affected by tenosynovitis alongtheir course or at insertion [30]. At a level proximalto the extensor retinaculum, these tendons maycause a clinical entity known as intersection syn-drome. This disorder occurs at the level where theextensor pollicis brevis and abductor pollicis longuscross over the extensor carpi radialis longus andbrevis and is usually attributed to activities with re-peated gripping, twisting, or turning actions, as mayoccur in a variety of sports or work-related activities.The third compartment extensor pollicis longustendon may be affected by tenosynovitis at the levelof Lister’s tubercle at the distal radius due to localfriction, predisposing to further tendon injury.This injury presents with local pain or, less often,crepitus [31]. The fourth compartment extensordigitorum and extensor indicis and the fifth com-partment tendon extensor digiti minimi are morefrequently involved in inflammatory disorderssuch as rheumatoid arthritis; however, they can

Fig. 24. de Quervain’s tenosynovitis. (A) Longitudinal imagmal fluid (arrow) surrounding the abductor pollicis longuslying the radial styloid. In addition, there is hypoechoic tissynovial thickening (arrowheads). (B) Transverse image simabductor pollicis longus (APL) and extensor pollicis brevis

also be affected in overuse settings. The extensorcarpi ulnaris tendon in the sixth compartmentmay be affected with tenosynovitis in addition todisorders associated with instability of the retinacu-lum. Retinaculum tears can occur with trauma,overuse, or inflammatory disorders. In overusesyndromes, tears may be due to local friction andsubluxation of the tendon against the ulna, asmight occur with repeated supination and prona-tion of the wrist, such as in tennis players [30,31].This disorder can be identified on ultrasound withdynamic scanning.

Flexor compartment

Flexor carpi ulnaris is the only tendon at the wristwithout a synovial sheath and is partially attachedto the anterior surface of the flexor retinaculum[32]. It can present with tendon disorders, mostcommonly calcific tendinopathy, often just proxi-mal to its insertion onto the pisiform bone [31].Flexor carpi radialis tendon pathology is commondue its anatomic position in a small fibro-osseoustunnel on the carpal surface. Tendinopathy changescan occur in the setting of first carpometacarpaljoint arthrosis or carpal fractures, particularly thoseinvolving the scaphoid [33]. Middle-aged womenare often affected and complain of pain and a local-ized lump over the volar aspect of the wrist.

There are two synovial sheaths enveloping thenine flexor tendons in the carpal tunnel. Onesurrounds the tendons of the flexor digitorumsuperficialis and flexor digitorum profundus, theother the tendon of flexor pollicis longus. Tenosyn-ovitis changes in the carpal tunnel may result inmedian nerve compromise and clinical presenta-tion of carpal tunnel syndrome.

e of the first extensor compartment identifies abnor-tendon (APL) in the first extensor compartment over-

sue at the margin of the sheath, indicating associatedilarly demonstrates the fluid (arrows) surrounding the(EPB) tendons.

Fig. 25. Abductor pollicis longus split tear. (A) Longitudinal image of the abductor pollicis longus tendon (APL) atthe level of the wrist demonstrates abnormal fusiform thickening of the tendon, with central hypoechoic cleft(arrowheads) consistent with a longitudinal split tear. (B) Extent of tear is also demonstrated on transverseimages (arrowheads). (Courtesy of J. Dhanju, RDMS, Toronto Canada.)


Hand

The anatomy of the hand and fingers is complex.Normal tendon and muscle function is critical tomaintain the multifaceted function of this compli-cated region.

Fig. 26. Mallet finger. Longitudinal image of thedistal finger at the level of the distal interphalangealjoint (DIP Jt) demonstrates discontinuity at the baseof the distal phalanx, consistent with a small boneavulsion injury (arrow). Associated tendon avulsionis identified with fluid filling the gap at expectedsite of extensor tendon insertion (arrowheads). Theproximal retracted tendon stump (asterisk) is visual-ized. (Courtesy of J. Dhanju, RDMS, Toronto, Canada.)

Extensor mechanism

The superficial finger extensor mechanism is predis-posed to injury with blunt and penetrating trauma.Traumatic tendon injuries are classified as open,closed, partial, or complete. With complete tendonlaceration, significant retraction may not occur, dueto the intricate tendon attachment system in the fin-ger. Ultrasound will demonstrate a complete ten-don laceration as an area of discontinuity, withfraying and irregularity of both ends of the rupturedtendon. The gap created between the torn ends ofthe tendon can be measured and localized by ultra-sound. In this setting, the treatment of choice is sur-gical repair. Partial tears present as focal hypoechoicor anechoic defects in the tendon. In the setting ofchronic tears, it can become difficult to separatefibrous tissue from torn tendon. Dynamic assess-ment observing loss of normal gliding tendon fiberscan assist with recognition.

Closed extensor tendon injuries include malletfinger, boutonniere deformity, and extensor hoodinjuries [34]. Mallet finger or baseball finger is themost common closed tendon injury in sports andis due to injury at the attachment of the extensortendon to the distal phalanx [35]. The injury resultsin a flexion deformity at the distal interphalangeal(DIP) joint and occurs as a result of an acute flexionat the DIP joint when the moving finger hits a sta-tionary object or is hit with a mobile object.

Because the affected individual is unable to activelyextend the DIP joint, dynamic scanning with pas-sive flexion and extension of the finger assists inidentification. Ultrasound will depict this disconti-nuity, particularly when there is no associated boneavulsion injury, but can identify both tendon andbone involvement (Fig. 26). Treatment is closedsplinting with the DIP in extension [36].

A boutonniere deformity is due to an avulsion in-jury of the central slip of the extensor tendon ontothe base of the middle phalanx and is the secondmost frequent extensor tendon injury [37]. This de-formity often presents chronically. With loss of thecentral slip, the head of the proximal phalanx ex-tends through the site of tear, creating the clinical


deformity. This tendon injury can occur secondaryto acute athletic injury; however, the deformitymay take a few weeks to present. In this instance,the tendon injury may be masked by swelling andimmobility and, as a result, this disorder may gounrecognized or misdiagnosed [36].

Extensor hood injuries most commonly involvethe middle finger and are often seen in boxers.The injury occurs due to tearing of the sagittal bandsof the extensor hood, which normally hold theextensor tendon in a midline position during fingerflexion and extension. Injury may occur as an acuteevent or secondary to repetitive microtrauma [37].Ultrasonography has the advantage over MR im-aging in the ability to demonstrate this disorderdynamically [38]. With complete tears, dynamicscanning typically demonstrates ulnar subluxationof the extensor tendon because the radial portionof the sagittal band is more commonly affectedwith this injury [37]. The abnormality is bestassessed on ultrasound with short-axis imaging(Fig. 27). In the acute phase, treatment is splint-ing; in chronic cases, surgery may be necessary.

Flexor mechanism

Flexor tendon injuries are less common than theirextensor counterpart. These injuries are also dividedinto open and closed injuries. An important injuryof the finger flexor mechanism involves the pulleysystem.

Open injuries to the flexor tendons from pene-trating wounds are more common than contusionsand usually involve the midsubstance of the tendonand rarely involve the point of bony insertion [39].In the finger, the flexor digitorum profundus ismore commonly lacerated due to its more superfi-cial position compared with the flexor digitorumsuperficialis tendon slips (Fig. 28) [37]. Penetrating

Fig. 27. Extensor hood injury. Transverse images of the exte(asterisks) identify the extensor tendon (interrupted line)sition (left image). With flexion (Flex), the extensor tendothe radial portion of the sagittal band (right image). (Co

injuries with resultant retained foreign bodies alsopose a significant risk of infectious tenosynovitis.

The most frequent closed flexor tendon injury isavulsion of the flexor digitorum profundus tendonof the fourth digit, usually caused by acute hyperex-tension during active flexion. This injury is alsoknown as jersey finger because the injury may occurwhen a finger is caught on another player’s jersey[36]. With this injury, the DIP joint cannot beactively flexed. The degree of tendon retractioninto the palm and the presence or absence ofassociated bone fragment can be assessed by ultra-sound and have important implications forsurgery. Surgical repair is the treatment of choice.Isolated rupture of the flexor digitorum superficialisis rare.

The flexor synovial sheath extends from the neckof the metacarpal to the DIP joint. A series of reti-nacular structures, which thicken the sheath atfive specific points, form the annular pulley system(pulleys A1–A5). Additional fibers that crisscrossbetween the annular pulleys create the cruciate orcruciform pulley system (pulleys C1–C3). Thesepulleys combine to prevent excursion of the flexortendons from the metacarpophalangeal and inter-phalangeal joints during finger flexion. Tenosynovi-tis changes can present secondary to direct traumaor overuse (Fig. 29). In the chronic overuse setting,tendon swelling can result in dysfunction. Triggerfinger (or stenosing tenosynovitis) is caused bya narrowing of the sheath that surrounds the ten-don of the affected finger, typically at the A1 pulleylevel. This narrowing serves as an ongoing source oftendon impingement, which results in increasingdifficulty with finger flexion and extension. Theterm trigger finger refers to the catching or lockingsensation experienced at this level as the finger tran-sitions from the flexed to extended position.

nsor tendon at the level of the third metacarpal headin normal midline position in the extended (Ext) po-n subluxes toward the ulnar side, indicating injury ofurtesy of J. Dhanju, RDMS, Toronto, Canada.)

Fig. 30. Trigger finger. Longitudinal image of theflexor pollicis longus tendon (FPL) identifies abnor-mal hypoechoic nodular synovial thickening overthe surface of the tendon (arrowheads) at the levelof the metacarpophalangeal joint (MCP Jt). Thisthickening was associated with a catching sensationon flexion and extension of the digit, indicating trig-ger finger. (Courtesy of J. Dhanju, RDMS, Toronto,Canada.)

Fig. 28. Partial-thickness tendon tear with penetrat-ing injury. Longitudinal image of the flexor digito-rum superficialis tendon (Flexor T) demonstratesa partial-thickness tear (arrow) involving the palmarsurface of the tendon, following a stabbing injurywith a knife.


‘‘Triggering’’ implies a more chronic process andmay be further contributed to by the developmentof soft tissue nodularity of the involved tendonsheath (Fig. 30). People who have work or hobbiesrequiring repetitive gripping actions are most sus-ceptible to this condition. It is more common inwomen than in men and in those who have diabe-tes [40]. Initial treatment is conservative, with rest,splinting, and steroid injection. Surgery may benecessary. To image, the transducer should beplaced in the longitudinal plane, usually at the levelof the distal metacarpals, using controlled exten-sion against resistance. Tendon and or synoviumcan be identified catching under the A1 flexorpulley during dynamic real-time scanning.

Injuries to the pulley system are increasing withthe growing popularity of extreme sports such asrock climbing [41]. The marked flexion of the

Fig. 29. Extensive tenosynovitis of the flexor tendonsof index finger. Longitudinal image of the flexor dig-iti indicis demonstrates fluid and extensive synovialthickening (asterisks) surrounding the flexor tendon,throughout its course. Sites of indentation (arrow-heads) indicate areas of relative constriction of thetendon sheath, secondary to the pulley mechanism.Proximal interphalangeal joint (PIP Jt). (Courtesy ofJ. Dhanju, RDMS, Toronto, Canada.)

fingers with metacarpophalangeal (MCP) joint ex-tension, proximal interphalageal (PIP) joint flex-ion, and DIP joint extension in this activity, alongwith the load of the climber’s body weight, leadsto extensive forces on the A2 and A3 pulleys andto subsequent rupture. Ultrasound can usually de-pict the normal A2 pulley as a focal thickening ofthe synovial sheath in the sagittal plane or asa thin (0.3–0.5-mm diameter) hyperechoic fibrillarline at the level of the proximal third of the proxi-mal phalanx on transverse imaging. The A4 pulleyappears as a subtle thickening of the synovialsheath at the level of the midpoint of the middlephalanx in the sagittal plane, whereas the A3 andA5 pulleys are not routinely visible [42]. In suspectA2 pulley tears, controlled flexion against resistanceis necessary, with the transducer placed longitudi-nally and transversely over the PIP joint and proxi-mal phalanx. A pulley tear is confirmed byabnormal separation of the flexor tendon fromthe underlying echogenic bony cortex, creatinga large gap between tendon and bone (bowstringappearance). Early diagnosis and degree of tear isessential in choosing conservative treatment or sur-gery and in preventing unwanted flexion contrac-ture of the PIP joint.

Summary

Ultrasound is a valuable diagnostic tool for imag-ing a great variety of soft tissue injuries of the mus-cles and tendons of the upper extremity. Theadvantages include real-time scanning, the abilityto use oblique imaging planes, the opportunity to


dynamically assess with compression, flexion, andextension, and to directly correlate to the areas ofpatient’s symptoms. It is extremely important touse excellent technique with high-resolutionequipment and to understand the anatomy of thescanned region of interest. In the appropriatesetting, ultrasound can offer a rapid and focuseddiagnosis for a variety of acute and chronic trau-matic conditions affecting the upper extremity.

References

[1] Crass JR, Craig EV, Feinberg SB. Clinical signifi-cance of sonographic findings in the abnormalbut intact rotator cuff: a preliminary report.J Clin Ultrasound 1988;16:313–27.

[2] Breazeale NM, Craig EV. Partial-thickness rotatorcuff tears: Pathogenesis and treatment. OrthopClin North Am 1997;28(2):145–55.

[3] Yamanka K, Fukuda H. Pathologic studies of thesupraspinatus tendon with reference to incom-plete partial thickness tear. In: Takagishi N, editor.The shoulder. Tokyo: Professional PostgraduateServices; 1987. p. 220–4.

[4] Ellman H. Diagnosis and treatment of incom-plete rotator cuff tears. Clin Orthop Relat Res1990;254:64–74.

[5] Weber SC. Arthroscopic debridement and acro-mioplasty versus mini-open repair in the man-agement of significant partial thickness tears ofthe rotator cuff. Orthop Clin North Am 1991;28:79–82.

[6] Payne LZ, Altchek DW, Craig EV, et al. Arthro-scopic treatment of partial thickness rotatorcuff tears in young athletes: a preliminary report.Am J Sports Med 1997;25:299–305.

[7] Bianchi S, Martinoli C. Shoulder. In: Baert AL,Knauth M, Sartor K, editors. Ultrasound of themusculoskeletal system. New York: Springer;2007. p. 189–331.

[8] Jacobson JA, Lancaster S, Prasad M, et al. Full-thickness and partial-thickness tendon tears:value of US signs in diagnosis. Radiology 2004;230:234–42.

[9] Bouffard JA, Lee SM, Dhanju J. Ultrasonographyof the shoulder. Semin Ultrasound CT MR 2000;21(3):164–91.

[10] Zanetti M, Weishaupt D, Jost B, et al. MR imag-ing for traumatic tears of the rotator cuff: highprevalence of greater tuberosity fractures andsubscapularis tendon tears. AJR Am J Roentgenol1999;172:463–7.

[11] Sofka CM, Haddad ZK, Adler RS. Detection ofmuscle atrophy on routine sonography of theshoulder. J Ultrasound Med 2004;23:1031–4.

[12] Travis RD, Doane R, Burkhead WZ. Tendonrupture about the shoulder. Orthop Clin NorthAm 2000;31(2):313–30.

[13] Beall DP, Williamson EE, Ly JQ, et al. Associa-tion of biceps tendon tears with rotator cuff

abnormalities: degree of correlation with tearsof the anterior and superior portions of the ro-tator cuff. AJR Am J Roentgenol 2003;180:633–9.

[14] Middleton WD, Remus WR, Totty WG, et al. Ul-trasonographic evaluation of the rotator cuff andbiceps tendon. J Bone Joint Surg Am 1986;68:440–50.

[15] Armstrong A, Teefey SA, Wu T, et al. The efficacyof ultrasound in the diagnosis of long head ofbiceps tendon pathology. J Shoulder ElbowSurg 2006;15:7–11.

[16] Bianchi S, Martinoli C, Abdelwaha IF. Ultra-sound of tendon tears. Part 1: general consider-ations and upper extremity. Skeletal Radiol2005;34:500–12.

[17] Farin PU, Jaroma H, Harju A, et al. Medial dis-placement of the biceps brachii tendon: evalua-tion with dynamic sonography during maximalexternal shoulder rotation. Radiology 1995;195:845–8.

[18] Bak K, Cameron EA, Henderson IJP. Rupture ofthe pectoralis major: a meta-analysis of 112cases. Knee Surg Sports Traumatol Arthrosc2000;8:113–9.

[19] Yichayaou B, Brinblat J, Katz M, et al. Pectoralismajor rupture in the elderly. Clinical and sono-graphic findings. Clin Imaging 2003;27(4):261–3.

[20] Zvijac JE, Schurhoff MR, Hechtman KS, et al.Pectoralis major tears: correlation of magneticresonance imaging and treatment strategies. AmJ Sports Med 2006;34:289–94.

[21] Rehman A, Robinson P. Sonographic evaluationof injuries to the pectoralis muscles. AJR AmJ Roentgenol 2005;184:1205–11.

[22] Blazar PE, Williams GR, Iannotti JP. Spontane-ous detachment of the deltoid muscle origin.J Shoulder Elbow Surg 1998;7:389–92.

[23] Thomas EA, Cassar-Pullicino VN, McCall IW.The role of ultrasound in the early diagnosisand management of heterotopic bone forma-tion. Clin Radiol 1991;43:190–6.

[24] Van Holsbeeck MT, Introcaso JH. Sonographyof muscle. In: Van Holsbeeck MT,Introcaso JH, editors. Musculoskeletal ultra-sound. 2nd edition. St. Louis (MO): Mosby;2001. p. 23–75.

[25] Miller TT, Adler RS. Sonography of the distalbiceps tendon. AJR Am J Roentgenol 2000;175:1081–6.

[26] Finlay K, Ferri M, Friedman L. Ultrasound of theelbow. Skeletal Radiol 2004;33(2):63–79.

[27] Lozano V, Alonso P. Sonographic detection ofthe distal biceps tendon rupture. J UltrasoundMed 1995;14:389–91.

[28] Connell D, Burke F, Coombs P, et al. Sono-graphic examination of lateral epicondylitis.AJR Am J Roentgenol 2001;176:777–82.

[29] Anzel SH, Covey KW, Weinr AD, et al. Disrup-tion of muscles and tendons: an analysis of1,042 cases. Surgery 1959;45:406–14.


[30] Daenen B, Houben G, Bauduin E, et al. Sonogra-phy in wrist tendon pathology. J Clin Ultrasound2004;32:462–9.

[31] Bianchi S, Martinoli C. Wrist. In: Baert AL,Knauth M, Sartor K, editors. Ultrasound of themusculoskeletal system. New York: Springer;2007. p. 425–94.

[32] Johnson D, Ellis H. Wrist and hand. In:Johnson D, Ellis H, editors. Gray’s anatomy.39th edition. London: Elsevier; 2005. p. 889–933.

[33] Parellada AJ, Morrison WB, Reiter SB, et al.Flexor carpi radialis tendinopathy: spectrum ofimaging findings and association with triscaphearthritis. Skeletal Radiol 2006;35:572–8.

[34] Scott SC. Closed injuries to the extensionmechanism of the digits. Hand Clin 2000;16:367–73.

[35] Posner MA. Injuries to the hand and wrist inathletes. Orthop Clin North Am 1977;8:593–618.

[36] Lee SJ, Montgomery K. Athletic hand injuries.Orthop Clin North Am 2002;33:547–54.

[37] Bianchi S, Martinoli C. Hand. In: Baert AL,Knauth M, Sartor K, editors. Ultrasound of themusculoskeletal system. New York: Springer;2007. p. 495–548.

[38] Van Holsbeeck MT. Sonography of the elbow,wrist and hand. In: Van Holsbeeck MT,Introcaso JH, editors. Musculoskeletal ultra-sound. 2nd edition. St. Louis (MO): Mosby;2001. p. 517–71.

[39] Folmar RC, Nelson CL, Phalen GS. Rupturesof flexor tendons in hands of nonrheumatoidpatients. J Bone Joint Surg Am 1972;54:579–84.

[40] Chammas M, Bousquet P, Renard E, et al. Du-puytren’s disease, carpal tunnel syndrome, trig-ger finger, and diabetes mellitus. J Hand SurgAm 1995;20(1):109–14.

[41] Claver JA, Alomar X, Monill JM, et al. MR imag-ing of ligament and tendon injuries of thefingers. Radiographics 2002;22:237–56.

[42] Lee JC, Healey JC. Normal sonographic anatomyof the wrist and hand. RadioGraphics 2005;25:1577–90.



595

Common Tendon and MuscleInjuries: Lower ExtremityTheodore T. Miller, MD, FACRa,b,*

- Sonographic appearance of injury- Hip and thigh

Abductor musclesSnapping hip syndromeIliopsoas tendonAdductor musclesTensor fascia lataRectus femoris muscleHamstrings

- Knee and calfDistal quadriceps tendon rupturePatellar tendinosis and tear

Jumper’s knee (patellar tendinitis)Osgood-Schlatter disease and

Sinding-Larsen–Johansson diseaseThe posterolateral cornerCalf

- AnkleAchilles tendonFlexor tendonsPeroneal tendons

- Summary- References

The lower extremity is the most commonly for further evaluation of soft tissue injury. Although
injured body part in many sports, affecting athletesat all levels of competition ranging from gradeschool to professional and elite amateur sports[1–4]. Although many injuries are sport-specific[5–10], common trends of muscle and tendoninjury affect both male and female athletes[4,11,12]. One large survey of high-school athletesin the United States in 2005 found that football wasthe most common cause of lower extremity injuriesin boys, whereas soccer was the most common ingirls; muscle strains and contusions were the secondand third most common injuries after ligament in-jury, with the ankle, knee, and thigh the three mostcommon sites of injury in descending order [3].
The imaging evaluation of the painful or injuredlower extremity should always begin with radio-graphs, but advanced imaging is often necessary

a Department of Radiology and Imaging, Hospital forNY 10021, USAb Weill Medical College of Cornell University, 1300 York* Department of Radiology and Imaging, Hospital foNY 10021.E-mail address: [email protected]


MR imaging is the gold standard, providing ananatomic overview and excellent demonstrationof the bony structures, articular surfaces, and thesurrounding soft tissues, sonography is quickly per-formed, has greater resolution than MR imaging[13], allows dynamic evaluation of tendons andmuscles, and can guide percutaneous procedures.Moreover, the advent of sonographic extended fieldof view imaging allows the demonstration of theentire length or cross-section of an area of interest,matching the ability of MR imaging to displaya large anatomic region.

Sonographic appearance of injury

Muscles usually tear at the muscle fiber–centraltendon attachment (the musculotendinous

Special Surgery, 535 East 70th Street, New York,

Avenue, New York, NY 10021, USAr Special Surgery, 535 East 70th Street, New York,




Miller596

junction), or less often at the myofascial junction ofthe epimysium along the superficial surface of themuscle. Sonographically, a muscle tear appears asdisruption of the normal pennate architecture,either with focal hyperechogenicity from interstitialhemorrhage or hypoechogenicity caused by frankhematoma formation. The outer fascial layer sur-rounding a muscle may occasionally tear, allowingthe muscle to herniate through the fascial rent dur-ing muscle contraction; dynamic scanning duringmuscle contraction can demonstrate the muscleherniation, whereas static imaging with the muscleat rest may fail to show the abnormality.

Tendon injury has a spectrum of appearances,depending on the severity and chronicity of theabnormality. Microtears caused by repetitive over-use lead to intrasubstance degeneration, whichmay demonstrate (1) areas of mucinous changethat manifest as replacement of the normal echo-genic fibrillar pattern by ill-defined hypoechoicregions; (2) neovascularity caused by angiofibro-blastic proliferation [14], which can be shownwith color or power Doppler imaging; or (3) echo-genic foci of calcification and heterotopic ossifica-tion. Continued microtearing may lead to franktear, which may be purely interstitial or involvethe tendon surface. Mild partial tearing may leadto tendon thickening and hypoechogenicity,whereas severe partial tearing causes thinning andattenuation of the tendon, similar to a frayingrope. Rupture of the tendon manifests as tendinousdiscontinuity, with or without retraction [15].

Caution should be exercised when scanning ten-dons to make sure that the sonographic beam isperpendicular to the tendinous structure in what-ever plane is being imaged; a nonorthogonal soundbeam may make the tendon look artifactuallyhypoechoic, mimicking tendinosis or tear, causedby anisotropy. Anisotropy is the property of highlyordered structures, such as tendons, ligaments,and nerves, to vary in their reflective echogenicity

Fig. 1. Anisotropy. (A) Transverse sonographic image of thbeam shows echogenic circular structures. PL arrow is the(B) Transverse sonographic image with the insonating bechogenicity of the two tendons (arrows).

depending on the angle of insonation of the inter-rogating sound beam (Fig. 1).

Hematoma can have a variable sonographicappearance. Some authors have reported a hypoe-choic appearance acutely, which becomes heteroge-neously hyperechoic as the hematoma organizes[16,17], whereas some have reported the reversetemporal appearance [18–20], and others havereported no correlation between time course andsonographic appearance [21].

Hip and thigh

Abductor muscles

An analogy can been made between the gluteusmedius and minimus tendons, which are abductorsof the hip, and the supraspinatus and infraspinatustendons, which assist in abduction of the shoulder.Thus, the gluteus medius and minimus have beentermed the rotator cuff of the hip [22]. Similar tothe tendons of the rotator cuff, the gluteus mediusand minimus tendons are subject to tendinosis,partial tear, and full thickness tear. The adjacentbursae may be concomitantly inflamed or merelydistended due to abnormality of the adjacent ten-don. The bursa most commonly involved is thesubgluteus maximus bursa, also called the greatertrochanteric bursa, which is larger than the subglu-teus minimus and subgluteal medius bursae, andwhich is located over the posterolateral aspect ofthe trochanter [23].

The greater trochanteric pain syndrome is charac-terized by pain and focal tenderness in the region ofthe greater trochanter, which is exacerbated withweight-bearing and hip abduction and usuallyaffects middle-aged and older women. It can becaused by tendinosis and partial or complete tearsof the gluteus medius or minimus tendons,inflammation of any of the three subgluteal bursae,or more commonly a combination of gluteal ten-don abnormality and gluteal bursitis. Most cases

e peroneal tendons with a perpendicular insonatingperoneus longus and PB arrow is the peroneus brevis.am at an angle other than 90� shows marked hypoe-

Tendon and Muscle Injuries: Lower 597

are caused by chronic degeneration and overuse,with only a few by prior local trauma [24–27].The fluid-distended bursae appear as discrete hypo-echoic or anechoic collections. The degeneratedtendon is thickened and may appear hypoechoic,and a partial tear appears as either a focal anechoicregion or a hypoechoic linear zone within thetendon (Fig. 2). A complete tear involves the fullthickness of the tendon and may or may not dem-onstrate retraction of the tendon (Figs. 3 and 4);the respective muscle may be atrophic, with lossof volume and increased echogenicity caused byfatty infiltration [28]. Using the appearances of bur-sitis, elongation of the gluteus medius tendon, andtendon discontinuity, Cvitanic and colleagues [25]achieved 93% sensitivity and 91% accuracy for diag-nosing tears of the abductor tendons, whereas Con-nell and colleagues [24] achieved 90% sensitivityand 95% specificity for tear. Connell and colleagues[24] also reported cortical irregularity of the greatertrochanter in 25 of 53 cases, analogous to that seenon the greater tuberosity of the humerus in rotatorcuff tears, and hyperemia on color or power Dopp-ler in only 9 of 53 hips.

Calcification of the gluteus minimus or mediustendon may also be encountered [24], an appearancethat has also been described radiographically [29].

Snapping hip syndrome

The snapping hip syndrome refers to a suddensnapping sensation during hip motion and can becaused by intraarticular and extraarticular causes[30–32]. Intraarticular causes include loose bodies(either from trauma, degenerative arthritis, or syno-vial osteochondromatosis) and labral tear, whereasextraarticular causes are caused by abnormal mo-tion of tendons. The extraarticular causes can befurther classified as lateral, or external, snapping,caused by abnormal motion of the iliotibial band

Fig. 2. Gluteus minimus tendinosis. (A) Longitudinal exgluteus medius and gluteus minimus muscles inserting ospur (arrow) arises from the trochanter. The gluteus minview of the greater trochanter shows a thickened and hyplinear hypoechoic tears along its deep surface (long whitethe subgluteus minimus bursa (black arrow) (also calledmedius tendon is more normal-appearing (short white ar

or gluteus maximus over the greater trochanter,and as medial, or internal, snapping, caused by ab-normal motion of the iliopsoas tendon over theiliopectineal eminence of the pelvis, the anteriorinferior iliac spine, or even the lesser trochanter[33]. Teenagers and young adults are typicallyaffected and may not have any predisposing occu-pational or athletic activity [31,32], although Jan-zen and colleagues [32] reported that four of eightpatients who had a snapping iliopsoas tendonexperienced a preceding traumatic event of hipabduction and external rotation. Regardless ofa medial or lateral origin, the snapping may ormay not be painful [30].

On static imaging, the offending tendon oftenlooks normal, although tendinosis, peritendinousfluid, and iliopsoas bursitis have occasionally beendescribed [30–32]. The imaging diagnosis is made,however, using dynamic sonography to documentthe snap or sudden jerk of the tendon. To evaluatea suspected snapping iliopsoas tendon, the trans-ducer is placed transversely over either the femoralhead or pectineal eminence of the pelvis, and thepatient, lying prone, is asked to flex, externally ro-tate, and abduct the femur (producing a frog lateralposition) and then move back to neutral position. Anormal iliopsoas tendon will have smooth move-ment, but a snapping one will show a sudden jerk,often with a palpable or audible snap. The snapmay occur from medial to lateral or vice versa; ante-rior to posterior; or a rotational movement on itself,and may occur during hip flexion to extension orvice versa [30]. The creation of a flash artifact fromthe fast-moving snap has also been described asa secondary sign of the snapping tendon [34].Even when snapping cannot be shown sonographi-cally, these patients may obtain pain relief from a so-nographically guided injection of steroid into theadjacent iliopsoas bursa [35].

tended field of view sonographic image shows then the greater trochanter. A small bony enthesophyteimus tendon is thickened and hypoechoic. (B) Closeroechoic gluteus minimus tendon (asterisk), with smallarrows). A small amount of anechoic fluid appears inthe deep trochanteric bursa). The overlying gluteusrow).

Fig. 5. Short axis sonographic image of the iliopsoastendon in a patient who has undergone total hipreplacement shows a thickened and ill-defined iliop-soas tendon (white arrow). The black arrow pointsto the pelvic brim.

Fig. 3. Short axis sonographic image of the greatertrochanter shows a hypoechoic full thickness tear ofthe anterior aspect of the gluteus medius tendon(white arrow). The posterior aspect of the tendon(black arrow) is present attaching to the posterioraspect of the lateral facet of the greater trochanter.

Miller598

To evaluate suspected snapping of the iliotibialband or gluteus maximus, the patient either laysdecubitus with the affected side up or standsupright, and the transducer is placed transverselyover the lateral aspect of the greater trochanterwhile the patient flexes and extends the hip. Alter-natively, the snapping may occur when the patientrotates the hip internally and externally.

Iliopsoas tendon

Patients who have had hip arthroplasty maydevelop pain in the groin or over the anterior aspectof the hip from impingement of the iliopsoas ten-don against the anterior aspect of the acetabularcup. Sonography can show the direct contact ofthe cup and the tendon, and the tendon may appearenlarged, ill-defined, or hypoechoic, and may havesurrounding or adjacent iliopsoas bursitis (Fig. 5).

Fig. 4. Longitudinal sonographic image of the greatertrochanter shows a torn and retracted gluteus mediustendon (short white arrow points to the tendonedge), and a small amount of hypoechoic fluid atthe bare attachment site (long white arrow). Theoverlying iliotibial band is present (black arrow).

However, in many instances direct impingement isnot confirmed and the tendon looks normal. Sono-graphically guided injection of steroid or anestheticaround the tendon and into the iliopsoas bursa atthe level of the acetabular rim can be diagnosticand therapeutic, but the definitive treatment isiliopsoas tenotomy [36].

Adductor muscles

The adductor muscle group is comprised of theadductor longus, adductor magnus, adductor bre-vis, pectineus, gracilis, and obturator externus[37]. Adductor muscle injuries are most oftenencountered in soccer, hockey, cricket, Australianrules football, and breaststroke swimmers [37–42], and are a common cause of groin pain inthese athletes. The adductor longus is most com-monly affected [33].

The strain can occur at the tendon origin on thesymphysis pubis [43], at the musculotendinousjunction [44,45], and at the distal insertion onthe femur (called thigh splints) [46–48]. Sonographyof the acutely injured adductors may show focalhypoechoic defects or gaps at the musculotendi-nous junction, a hypoechoic acute hematoma,hyperemia with color or power Doppler, or corticalirregularity of the bone at either the symphysispubis attachment or the femoral attachment(Fig. 6) [44–46]. Goh and colleagues [44] reportedsonographically guided aspiration of a hematomawithin a tear of the adductor muscles of the groin,followed by two courses of injection of anestheticand steroid into the tear, 7 weeks apart, with com-plete resolution of groin pain. The chronicallytorn muscle will exhibit decreased bulk andincreased echogenicity from fatty atrophy [48].

Fig. 7. Longitudinal sonographic image at the level ofthe hip shows a partial avulsion of the direct head ofthe rectus femoris muscle with a hypoechoic cleft(open arrow) between the muscle and the anteriorinferior iliac spine (AIIS), and a small fragment ofavulsed echogenic bone (white arrow). The indirecthead of the rectus femoris muscle and femoral headare identified in this image.

Fig. 6. Short axis sonographic image in a patient withleft sided groin pain shows hypoechogenicity of theadductor origin (asterisk) and cortical irregularity(white arrows) of the anterior aspect of the superiorpubic ramus. (Case courtesy of Dr. Levon Nazarian,Philadelphia, PA.)


Tensor fascia lata

Unilateral enlargement of the tensor fascia lata mayoccur because of degeneration and overuse. In Bassand Connell’s [49] series of 12 patients, all com-plained of anterior groin pain and point tendernessover the anterior iliac crest and all were engaged inathletic activities. Sonography in all of thesepatients showed enlargement of the tensor fascialata with a cone-shaped region of hypoechogenicityat its origin, and a linear anechoic intrasubstancetear of the muscle in three patients. The unilateralenlargement may also mimic a soft tissue mass,prompting imaging evaluation [50]; two cases oftear of the tensor fascia lata reported by Asingerand El-Khoury [51] also presented as soft tissuemasses from retraction of the avulsed muscle.

Rectus femoris muscle

The rectus femoris muscle is the most anterior of thequadriceps group and has two proximal origins fromthe pelvis. The direct head of the rectus femoris mus-cle arises from the anterior inferior iliac spine andgives rise to a superficial aponeurosis and unipen-nate muscle structure, whereas the indirect headoriginates from the supra-acetabular region andgives rise to the central tendon of the muscle witha bipennate muscle structure. This configuration ofouter unipennate fibers and inner bipennate fibersgives a ‘‘muscle within a muscle’’ appearance on axialsonographic images, with the central tendon havingan echogenic linear appearance [52].

Like the hamstring muscles, the rectus femorismuscle is composed mostly of type 2 fibers, crossestwo joints, and has two heads of origin, all of whichmake it susceptible to tear from sports requiringa sudden forceful contraction, either from hip flex-ion or knee extension, such as sprinting or kickinga ball [53]. Tears of the rectus femoris muscle are

more common at the distal musculotendinousjunction near the quadriceps tendon but may alsooccur proximally (Fig. 7).

Bianchi and colleagues [52] described threesonographic patterns of rectus femoris muscleinjury: type 1, a mild partial tear, appearing ashyperechogenicity in the center of the musclecaused by hemorrhagic infiltration, obscuring thecentral hyperechoic central tendon (Fig. 8); type 2,a moderate partial tear, appearing either as mixedhypo- and hyperechogenicity (Fig. 9) or a ‘‘bull’seye’’ configuration with hypoechoic hematomasurrounding the echogenic central tendon and anouter rim of echogenic hemorrhagic infiltration;and type 3, complete musculotendinous disrup-tion, with the echogenic central tendon coursingthrough a large hypoechoic hematoma with retrac-tion of the torn muscle fibers (Fig. 10).

In skeletally immature athletes, forceful flexionof the hip, such as in sprinting or kicking, can causeavulsion of the anterior iliac spine apophysis by thedirect head of the rectus femoris, representinga Salter 1 injury, rather than cause tear of the muscleitself as in adults. Longitudinal scanning over theanterior inferior iliac spine will demonstrate thedisplaced thin echogenic surface of the avulsedapophysis [54].

Hamstrings

The hamstring group comprises the biceps femoris,semimembranosus, and semitendinosus muscles.The long head of the biceps femoris and the semi-membranosus and semitendinosus muscles

Fig. 8. Short axis sonographic image of the rectusfemoris muscle shows a wedge shaped area of fainthyperechogenicity (short white arrows) indicatinghemorrhage adjacent to the echogenic linear centraltendon (long white arrow).

Miller600

originate from the ischial tuberosity of the pelvis,and the short head of the biceps femoris originatesfrom the femoral shaft. The distal biceps femoristendon inserts on the fibular head after joiningwith the fibular collateral ligament, the semimem-branosus inserts on the posterior aspect of themedial side of the proximal tibia, and the semite-ndinosus tendon inserts on the anterior aspect ofthe medial side of the proximal tibia as one of thepes anserinus tendons.

Sports that involve sprinting or quick accelera-tion may lead to hamstring injury. In soccer, mosthamstring injuries occur while running, with only7% caused by player-to-player contact [55]. Musclestrain is related to the extreme tensile forces gener-ated during sprinting. Because the forces generatedby the muscle contraction are complex, susceptiblemuscles are those that are composed of a highproportion of type 2 muscle fibers (because theyproduce a more powerful contraction than type 1fibers) and muscles that cross two joints and havemore than one head of origin (eg, the bicepsfemoris) [53]. Muscle fatigue also contributes to in-jury, with 47% of injuries in professional soccerplayers occurring toward the end of each half of

play [55]. Previous hamstring injury is also a riskfactor for repeat injury [55], and older players(>22 years of age) are more often injured thanyounger players (17–22 years of age) [55,56].

The biceps femoris is the most commonly injuredhamstring muscle, followed by the semimembrano-sus, and lastly the semitendinosus [57,58]. In oneseries, 5% of injuries involved more than one mus-cle [57]. Tear of the hamstrings most often involvesthe musculotendinous junction, occurring in 52%to 76% of cases [57–59], followed by the myofas-cial junction of the epimysium in 35% of cases[57,58]. Avulsion of the proximal or distal tendonsthemselves is rare, with 16 cases of proximal tendonavulsion, one case of distal biceps femoris avulsion,and three cases of distal semitendinosus tendonavulsion in a series of 170 patients [58].

The sonographic appearance of muscle injury isthe same as that already described for the rectusfemoris muscle. Intramuscular bleeding caused bymild tearing is hyperechoic. More extensive tearingappears as focal hypoechoic edema, typically adja-cent to the linear echogenic central tendon (themusculotendinous junction), and disruption ofthe pennate architecture of the muscle [57,58].

MR imaging is more sensitive than sonographyfor detecting mild muscle strain because of itsgreater soft tissue contrast [58]; in a series of ham-string injuries imaged with MR imaging and sonog-raphy, the abnormalities always appeared larger onMR imaging because of the greater soft tissuecontrast and consequent better conspicuity of mus-cle edema [57].

Sonography is less accurate than MR imaging fordiagnosing proximal hamstring avulsion, becausethe presence of a mixed echogenicity hematomaand the deep location of the ischial tuberosity, par-ticularly in heavy or muscular patients, can makedetection of the avulsed tendon difficult [58]. Kou-louris and Connell [58] found that MR imagingcorrectly identified acute avulsion from the ischiumin 16 of 16 cases, whereas sonography only diag-nosed 7 of 12 cases.

Fig. 9. Longitudinal ex-tended field of view sono-graphic image of theanterior aspect of the thighshows a partial tear of therectus femoris muscle withan anechoic hematoma(asterisk), linear anechoicinterstitial tearing (arrow),and generalized hypere-choic disruption of the pen-nate appearance caused byinterstitial bleeding.

Fig. 10. Rectus femoris muscle tear. (A) Longitudinal sonographic image of the anterior aspect of the thighshows a complete tear of the rectus femoris muscle at the musculotendinous junction. The proximal and distalextents of the tear are outlined by the asterisks; portions of the torn muscle are demonstrated by the round tailarrows, the straight white arrows point to the central tendon, and the black arrow points to fibrinous materialwithin the tear. (B) Corresponding coronal proton density MR imaging, oriented to match the sonographicimage, shows the high signal intensity hematoma, the torn muscle (round tail arrow), the central tendon(straight white arrows), and the focal fibrinous material (black arrow).


In addition to the objective demonstration ofmuscle injury that can confirm a clinical diagnosis,both MR imaging and sonography have been usedto predict time to return to activity. In two series,MR imaging showed no abnormality in 18% to31% of patients who had clinical hamstring injury[56,60], and patients who had no imaging evidenceof injury returned to competition sooner than thosewho had demonstrable abnormalities.

In a study of 60 soccer players who had acutehamstring injury clinically, sonography was slightlymore sensitive than MR imaging for detecting strain(75% versus 70%), but the length of the strain onMR imaging had the best statistical correlationwith time to recovery [57]. Similarly, other studieshave found that length and cross-sectional area ofmuscle injury on MR imaging and involvement ofthe central tendon are important prognostic indica-tors for time to recovery [61,62]. In one study ofpatients who had positive MR imaging or sono-graphic examinations, longitudinal length of tearon MR imaging was the best predictor of time toreturn to competition [57]. In a different study,the percentage of abnormal muscle area and vol-ume of muscle injured correlated with the numberof days lost from competition [59]. The risk forrecurrent hamstring injury increases with largersize of initial injury; recurrence risk is more thantwofold if the transverse size of the injury is 55%or more of the muscle or the volume of injury ismore than 21.8 cm3 [63].

Knee and calf

Distal quadriceps tendon rupture

The quadriceps tendon is the conglomeration ofthe distal tendons of the rectus femoris, vastus lat-eralis, vastus intermedius, and vastus medialismuscles, and is a long, broad tendon that inserts

on the anterior aspect of the superior pole of thepatella.

The cause of tears is eccentric contraction of theextensor mechanism, usually caused by stumbling,as the flexing knee tries to extend against the per-son’s weight. The ruptured tendon usually hassome underlying abnormality, such as tendinosusor generalized weakening, caused by a systemicchronic medical condition such as diabetes, chronicrenal failure, rheumatoid arthritis, or chronic ste-roid therapy. Tear is more common in people olderthan 40 years than in teenagers or young adults[64].

Partial tearing usually appears as a hypoechoiccleft in the tendon, and scanning should be per-formed in the long and short axis to determinethe extent of the injury. Rupture is complete discon-tinuity of the tendon (Fig. 11), and longitudinalscanning is useful to assess tendon discontinuityand the amount of retraction. When the torn edgesare apposed to each other, longitudinal scanningwith the knee flexed can distinguish a partial tearfrom a nonretracted rupture [65,66].

Patellar tendinosis and tear

The patellar tendon is the continuation of the quad-riceps tendon, comprised mostly of the rectus fem-oris component, which passes over the anterioraspect of the patella and inserts on the tibial tuber-cle. The normal patellar tendon is less than 75%of the thickness of the quadriceps tendon and hasparallel surfaces.

Patellar tendinosis is seen in adults and mayoccur anywhere along the patellar tendon. Thedevelopment of tendinosis is related to the ageand weight of a person [67]. Histologic analysis oftendon degeneration shows crimping and disorga-nization of collagen fibers and mucinous degenera-tion of collagen. Neovascularization caused by

Fig. 11. Longitudinal ex-tended field of viewsonographic image ofa quadriceps tendon tearshows the ruptured and re-tracted tendon edge (shortwhite arrow) with hypere-choic bone fragment andshadowing (long whitearrow). Anechoic edemaand echogenic hemorrhageare present in the tendongap (asterisk). P, patella.

Miller602

angiofibroblastic proliferation may also be present[14]. Sonographically, tendinosis appears as hypoe-choic loss of the normal echogenic fibrillar appear-ance of the tendon and tendon thickening(Fig. 12). Power or color Doppler imaging mayshow hyperemia of neovascularity.

Rupture of the patellar tendon, manifested sono-graphically as discontinuity of the tendon, mostoften occurs at the proximal aspect of the tendon,usually through an area weakened by tendinosisor previous surgery (Fig. 13). Rupture of the tendonat its midportion usually results from a direct blow.Patellar tendon rupture is less common than quad-riceps tendon rupture, tends to occur in youngeradults, and is more common in men than woman.In older adults, the same systemic diseases that arerisk factors for quadriceps tendon tear, namely dia-betes, chronic renal failure, rheumatoid arthritis,and chronic steroid therapy, are also risk factorsfor patellar tendon rupture [68].

Jumper’s knee (patellar tendinitis)

Jumper’s knee refers to a symptomatic focus of tendi-nosis and partial tearing that occurs in the proximalaspect of the patellar tendon, and gets its namebecause it is seen in basketball players, volleyballplayers, and other athletes whose sport requires

Fig. 12. Patellar tendinosis. (A) Longitudinal sonographicened and heterogenously echogenic patellar tendon (blacthe tibial insertion (T). (B) Longitudinal sonographic imagarrows) shows the normal echogenic fibrillar appearance

repetitive forceful extension of the knee [69]. Ina study of 613 elite athletes representing nine sports,the overall prevalence was 14%, with 45% in volley-ball, 32% in basketball, and 0% in cycling [69]. Thisinjury usually occurs in teenagers and young adults,and occurs in the proximal aspect of the tendonbecause the tensile stress transmitted through thetendon is greatest at the patellar insertion.

Pathologically, crimping and mucoid degenera-tion of the collagen fibers and angiofibroblasticproliferation occur, with eventual partial tearing.The term tendinitis is a misnomer because no acuteinflammation is seen histologically [70].

The normal patellar tendon has an echogeniccoarse fibrillar pattern, but in Jumper’s knee thefibrillar appearance is effaced by hypoechogenicityand the tendon is fusiform thickened. However,the cause of pain associated with the sonographicappearance is not well understood because thesegrayscale sonographic findings may be seen inboth symptomatic and asymptomatic individuals,and symptomatic athletes may be sonographicallynormal [71–73]. Conversely, in a study of 134 eliteteenage basketball players, 22% of clinically normaltendons had sonographically abnormal foci [74].Moreover, the grayscale appearances may resolve,persist, or enlarge, without any relation to

image of the patella tendon shows a markedly thick-k arrows), extending from the patellar insertion (P) toe of a normal patellar tendon for comparison (blackand parallel borders.

Fig. 13. Longitudinal ex-tended field of view sono-graphic image of a patellartendon rupture showsa thickened tendon withtendinosis and rupturededges (white arrows arethe proximal tendon edgeand black arrows are thedistal tendon edge), withintervening heterogeneoushypoechoic and echogenicedema and fibrinous mate-rial. P, patella; T, tibia.


symptoms [75,76]. Nonetheless, asymptomaticathletes who have a hypoechoic focus have a fourtimes greater risk for developing symptoms thanasymptomatic controls [75], and athletes whohave no symptoms and normal sonography haveonly an 8% risk for developing jumper’s knee [77].

Power or color Doppler imaging of the degener-ated tendon may show hyperemia, reflecting angio-fibroblastic proliferation (Fig. 14). The presence ofneovascularity in the degenerated tendon may bethe clue to symptomatology [78,79], but the find-ings are controversial because 8 of 20 symptomaticfoci in one study lacked vascularity on power Dopp-ler imaging [71] and 10 asymptomatic tendons inanother study had both grayscale and Dopplerabnormalities [72].

Osgood-Schlatter diseaseand Sinding-Larsen–Johansson disease

Osgood-Schlatter disease (OSD) and Sinding-Larsen Johansson disease (SLJD) are chronicoveruse injuries seen in sports involving forcefulcontraction of the extensor mechanism, such asencountered in cutting maneuvers and jumping.Whether patella alta, patella infera, or tibial torsionpredisposes to OSD because of altered tensile stress

Fig. 14. Jumper’s knee. (A) Longitudinal sonographic imagfusiform thickening (white arrows) and ill-defined interstitgraphic image with power Doppler imaging shows marke

on the patellar tendon–tibial tubercle apophysealattachment is debated [80].

These abnormalities affect adolescents, before thepatella is completely ossified and before the tibialtubercle apophysis has fused. Girls may be affectedat a slightly younger age than boys. OSD affects thedistal aspect of the patellar tendon, whereas SLJDaffects the proximal aspect of the tendon.

SLJD proximally and OSD distally are caused byrepetitive partial tearing of the tendon and smallavulsions of the cartilaginous attachment of the pa-tellar tendon to the lower pole of the patella andtibial tubercle apophysis, respectively. The smallavulsed cartilage fragments may ossify, and thesmall tendon tears may eventually cause the forma-tion of foci of heterotopic ossification [80–82].

Radiographically, OSD and SLJD show hetero-topic ossification within the patellar tendon, butnormal variations in development of the ossifica-tion centers of the tibial tubercle apophysis andlower pole of the patella may mimic heterotopicossification. The distinguishing feature of theseconditions from normal variations is the presenceof tendon thickening and soft tissue swelling andthe clinical presence of pain and tenderness in theaffected region.

e of the proximal aspect of the patella tendon showsial hypoechogenicity (asterisk). (B) Longitudinal sono-d internal and peritendinous hyperemia.

Miller604

Sonography of OSD and SLJD shows the thick-ened tendon with loss of the echogenic fibrillarappearance. Foci of heterotopic ossification willhave echogenic surfaces with varying amounts ofposterior acoustic shadowing. Distension of thedeep infrapatellar bursa is sometimes present andappears as a hypoechoic collection deep to the dis-tal aspect of the tendon (Fig. 15).

The posterolateral corner

The posterolateral corner of the knee is stabilized bya complex combination of ligaments and tendons.Static stabilization is provided by the fibular collat-eral ligament, arcuate ligament, popliteus tendon,popliteofibular ligament, and fabellofibular liga-ment. Dynamic stabilization is provided by thepopliteus, biceps femoris, and lateral gastrocne-mius muscles. The distal tendon of the biceps fem-oris and the fibular collateral ligament blendtogether at their insertion on the fibular head toform the conjoined tendon [83–85]. Of these stabi-lizers, the fibular collateral ligament, popliteofibu-lar ligament, and popliteus muscle and tendonare the most important [86].

These structures have been identified sonographi-cally in cadavers [87], but the efficacy of sonographyfor evaluating the acutely injured posterolateralstructures has not been determined. Moreover, thesestructures are usually part of a larger injury patternresulting from a combination of hyperextensionwith either varus force or external rotation of thetibia that also includes the anterior and posteriorcruciate ligaments, the medial collateral ligament,and menisci [83,84,86,88].

Calf

The plantaris, gastrocnemius, and soleus musclesare located in the superficial posterior compartment

Fig. 15. Longitudinal sonographic image of the distalaspect of the patella tendon in a patient with Os-good-Schlatter disease shows a normal appearing dis-tal patellar tendon (black arrows) that is thickenedand hypoechoic distally and contains an echogenicfocus of heterotopic ossification (large black arrow).T, tibia.

of the leg, and constitute the triceps surae. The gas-trocnemius muscle is the most superficial; it hasmedial and lateral heads arising from the posterioraspects of the respective femoral condyles andbecomes tendinous approximately midway downthe leg, merging with the fibers of the soleus muscleto become the Achilles tendon. The soleus muscle isdeep to the gastrocnemius and arises from the pos-terior aspects of the proximal tibia and fibula.

The plantaris muscle arises from the lateral fem-oral condyle, superior and medial to the origin ofthe lateral head of the gastrocnemius muscle; theplantaris muscle belly is short and small, and tapersto a long tendon at the level of the proximal tibia.The plantaris tendon courses medially, runningbetween the medial head of the gastrocnemiusmuscle and soleus muscle, and along the medialaspect of the Achilles tendon, to insert on the calca-neus. Thus, the gastrocnemius and plantaris mus-cles span the knee and ankle joints. The plantarismuscle is anatomically inconstant, being absent in7% to 20% of people [89].

Tennis leg refers to tear of the medial gastrocne-mius muscle or plantaris muscle. Both muscles arecomposed of type 2 (fast) muscle fibers and crosstwo joints, factors that increase the risk for injury[53,89]. The actions of dorsiflexion of the footand extension of the knee can cause overstretchingof either muscle [90]. Patients report acute sponta-neous pain in the calf, often associated with a pop-ping sensation. In one series of 30 patients,symptoms occurred while playing soccer in 22 casesand during tennis in 8 [91]. However, injury mayalso occur during routine activity.

Tennis leg most often affects middle-aged people,usually men, with an average age of 39 years in oneseries [90] and 45 years in another [89], but its prev-alence is unknown. Although injury of either thegastrocnemius or plantaris muscles may producesymptoms that are clinically regarded as tennisleg, the gastrocnemius muscle is usually affected.In a series of 141 patients who had clinical tennisleg examined sonographically, 94 had injury ofthe medial head of the gastrocnemius muscle, 2had plantaris tendon ruptures, and 1 had tear ofthe soleus muscle [89].

Injury of the medial head of the gastrocnemiusmuscle may be either partial tear or complete ruptureand occurs at the musculotendinous junction. Com-plete rupture was more common in the two seriesreported by Kwak and colleagues [90,91], whereaspartial tear was more common in the series of 65patients reported by Bianchi and colleagues [92].

Partial tear of the medial head of the gastrocne-mius muscle appears as focal disruption of the pen-nate appearance of the musculotendinous junctionof the muscle (Fig. 16) or as anechoic edema or

Fig. 16. Longitudinal ex-tended field of view sono-graphic image of the calfshows a tear of the gastroc-nemius muscle with hetero-geneous disruption of thenormal pennate appear-ance (white arrows) anda distal area of echogenic-ity (black arrow) represent-ing interstitial blood.


hematoma tracking along the central tendon(Fig. 17), whereas rupture appears as complete dis-continuity [89–92]. The transverse plane is best fordistinguishing the two. An initially hypoechoichematoma is often present between the gastrocne-mius and soleus muscles, which becomes echogen-ic over 1 to 2 weeks [90,92]. Kwak and colleagues[90,91] also report the development of echogenicfibrous tissue between the torn muscle and tendonat 2 to 4 weeks after injury, as part of the healingprocess, with eventual bridging of the tear. Bianchiand colleagues noted [92] similar hyperechoic scarin the patients who were rescanned sonographically1 year or more after the initial injury.

Injury of the plantaris may affect the muscle,musculotendinous junction, or the tendon itself[93,94]. In a series of 15 patients, Helms and col-leagues [93] found that 3 had rupture at the muscu-lotendinous junction and the remainder hadmuscle strains; 10 of the patients who had plantarismuscle strains also had anterior cruciate ligamenttears. Plantaris rupture appears as tendinous dis-continuity, with retraction of the echogenic tendon[89,94]. A large hypoechoic hematoma is oftenpresent between the medial head of the gastrocne-mius and soleus muscles.

Ankle

The ankle is often the most commonly injuredregion of the lower extremity, usually from an inver-sion injury resulting in a twisted or sprained ankleconsisting of ligamentous injury [3]. In contrast,the Achilles, flexor, and peroneal tendons are sub-ject to overuse and may become symptomatic

Fig. 17. Longitudinal extended field of view sonographicmusculotendinous tear of the gastrocnemius muscle withtral tendon (black arrow).

from tendinosis; tendinosis in turn predisposes topartial tear and rupture [95,96].

Achilles tendon

The Achilles tendon is formed by the tendinouscontributions of the gastrocnemius and soleus mus-cles. It is a long broad tendon, inserting on the pos-terior aspect of the calcaneus, and has the greatesttensile strength of any human tendon [97]. Achillesinjury is usually the result of overuse, typicallyencountered in athletic activities that involvechronic repetitive tensile forces such as runningand jumping [98], but numerous contributing fac-tors have been described including anatomic varia-tions such as mild limb length discrepancy andhyperpronation and varus alignment of the affectedfoot, calf muscle weakness and fatigue, and variouserrors in training [99].

Although many terms have been used to describeAchilles abnormalities, the term tendinopathy isa clinical term describing pain, swelling, and resul-tant decreased athletic capability [99,100], whereastendinosis refers to the structural changes of degener-ation seen histologically or with imaging [99].

The processes of tendinopathy and tendinosiscan be mutually exclusive. In 83 patients who hadclinical tendinopathy, tendinous changes wereseen sonographically in 29 (35%), with the remain-ing symptomatic cases showing no intratendinouschanges; 18 asymptomatic tendons showed sono-graphic abnormalities [101]. Similarly, in a differentstudy of 45 patients who had clinical tendinopathy,20 of 57 clinically abnormal tendons were normalsonographically, whereas 9 of 28 clinically normal

image through the calf shows a large full-thicknessan anechoic hematoma (asterisk) adjacent to the cen-

Fig. 18. Longitudinal ex-tended field of view sono-graphic image of theAchilles tendon shows ten-dinosis manifest by fusi-form thickening (whitearrows) of the tendon andinternal hypoechogenicity.

Miller606

tendons were sonographically abnormal [102].Although some studies have shown that symptom-atic patients who have normal sonography havea significantly better clinical outcome than patientswho have sonographic abnormalities [103,104],Khan and colleagues [102] found the severity ofthe ultrasound findings at baseline was not associ-ated with clinical outcome 1 year later.

Tendinosis and tears usually involve the proximaltwo thirds of the tendon [105]. Insertional tendino-sis, defined as degeneration occurring in the distalthird of the tendon, accounts for 8% to 25% ofcases of Achilles tendinopathy [105,106] and tendsto occur in older, less-active, or heavier individuals[106].

Tendinosis (intrasubstance degeneration)appears as focal hypoechogenicity replacing thenormal echogenic fibrillar architecture, usually butnot always associated with focal enlargement ofthe tendon (Fig. 18), and foci of echogenic calcifi-cation may be present in the tendon (Fig. 19).Intrasubstance partial tear is usually a more well-defined hypoechoic cleft or focus (Fig. 20), but dis-tinction between tendinosis and intrasubstancepartial tear can be difficult [107]. Power or colorDoppler imaging may show neovascularity fromdegenerative angiofibroblastic proliferation(Fig. 21). Abnormality of the paratenon has beendescribed as an ill-defined or fluid-like rim aroundthe tendon but is not reliably shown [107].

Rupture of the Achilles tendon appears as com-plete disruption of the fibrillar echogenic appear-ance of the tendon with or without retraction(Fig. 22). In acute ruptures, heterogeneous echo-genic edema and hemorrhage are often presentbetween the torn tendon edges. Sensitivity of ultra-sound for diagnosing Achilles tendon rupture is

96% to 100% and specificity is 83% to 100%[107,108].

Features associated with acute rupture are tendonretraction; posterior acoustic shadowing caused byrefractive shadowing of the sound beam by the dis-rupted and curled tendon edges; tendon thinness;herniation of Kager’s fat into the tendon gap; andvisualization of the plantaris tendon (along themedial aspect of the Achilles tendon), which is usu-ally silhouetted by the adjacent Achilles [108].Healed ruptures usually appear as a focally thick-ened region with variable presence of fiber distor-tion, hypoechogenicity, and calcification [109,110].

The clinical significance of the vascularity in theAchilles tendon, shown either with color or powerDoppler sonography, is controversial. Some serieshave shown the presence of vascularity in symp-tomatic tendons but not in asymptomatic tendons[111,112], and have reported therapeutic pain reliefafter sonographically guided sclerotherapy of thevessels [113,114]. However, other investigatorshave found vascularity in asymptomatic individuals[10,115]. Boesen and colleagues [10,115] haveshown increased vascularity in the Achilles tendonafter exercise, even in asymptomatic people,whereas other investigators have shown a correla-tion of vascularity with increasing thickness of thetendon [116,117], perhaps reflecting a greater de-gree of degeneration.

Flexor tendons

The posterior tibial tendon (PTT), flexor digitorumlongus tendon, and flexor hallucis longus tendonare contained within the tibial tunnel in the poster-omedial aspect of the ankle. The PTT is normallyalmost twice the diameter of the flexor digitorumlongus tendon, and both may normally have

Fig. 19. Longitudinal ex-tended field of view sono-graphic image of Achillestendinosis shows fusiformthickening with internalechogenic calcification(arrows).

Fig. 20. Short-axis sonographic image of the Achillestendon shows a focal well-defined anechoic tear(white arrow), adjacent to an ill-defined and heterog-enous region of tendinosis (black arrows).


a thin rind of surrounding hypoechoic fluid[118,119].

The PTT is the most commonly abnormal flexortendon, usually representing chronic degenerationand eventual tearing, occurring in middle- to old-er-aged adults and more often affecting women.Because the PTT is the major stabilizer of the medialcolumn of the foot, dysfunction of the tendon

Fig. 21. Achilles insertional tendinosis with neovascularization of the Achilles tendon shows abnormal fusiform thichypoechogenicity (black arrows). (B) Longitudinal sonograison shows the normal echogenic fibrillar and straightpower Doppler image of the patient’s affected side (samthe area of tendinosis.

presents clinically with medial ankle pain, loss ofthe medial arch of the foot, hindfoot valgus, andforefoot abduction [120,121].

The sonographic appearance of PTT tendinosis isthickening of the tendon with ill-defined hypoe-choic foci replacing the normal echogenic fibrillarappearance; linear well-defined hypoechoic focimay represent interstitial tears, whereas globularfoci may represent focal mucoid degeneration.Hypoechoic fluid may be present surrounding thetendon, or the tendon sheath may be thickened(Figs. 23–25). Extensive partial tears may causethinning of the tendon, and rupture is shown ascomplete tendinous discontinuity [122,123].

Using MR imaging as the gold standard, Premku-mar and colleagues [123] found that ultrasoundhad 80% sensitivity and 90% specificity for detect-ing tendinous abnormalities, and 90% sensitivityand 80% specificity for peritendinous changessuch as fluid in the tendon sheath and hyperemiaof the tendon sheath on Doppler imaging. MRimaging, however, may not be an accurate goldstandard, because Nallamshetty and colleagues[122] found a 77% concordance between MR imag-ing and ultrasound for evaluating PTT pathology,and the five discordant cases were more in

tion. (A) Longitudinal sonographic image of the inser-kening (white arrows) with a focal area of interstitialphic image of a normal tendon insertion for compar-

appearance of the Achilles tendon. (C) Longitudinale tendon as image A) shows neovascularization in

Fig. 22. Longitudinal ex-tended field of view sono-graphic image of anAchilles tendon ruptureshows the torn offset edgesof the ruptured tendon(white arrows). The distalaspect of the tendon ismarkedly thickened andhypoechoic.

Miller608

agreement clinically with ultrasound than the MRimaging interpretation. In a study of surgically cre-ated PTT tears in cadavers, Gerling and colleagues[120] found that both imaging modalities had72% accuracy, with a positive predictive value of88% for MR imaging and 92% for ultrasound.

Lim and colleagues [124] described fluid in thePTT sheath, a tibial spur on the distal posteriorouter margin of the medial malleolus, unroofingof the talar head on axial images resulting fromforefoot abduction and hindfoot valgus, and tibialmarrow edema as secondary finding of PTT dys-function on MR imaging. However, caution shouldbe exercised, because a thin rind of fluid may nor-mally surround the PTT [118], tibial spurring hashigh specificity but low sensitivity [124], reactivemarrow edema cannot be detected sonographically,and unroofing of the talar head has not been quan-tified sonographically. Moreover, the structuralchanges in foot alignment that result from PTT dys-function are not solely from an abnormality of thePTT itself; the superomedial and inferomedial com-ponents of the spring ligament complex and talo-calcaneal interosseous ligament of the sinus tarsiare also abnormal [125], but the ability of sonogra-phy to show these ligaments has not been assessed.

Fig. 23. Posterior tibial tendinosis and tenosynovitis. (A) Shposterior tibial tendon (white arrow) and an adjacent nothin normal amount of anechoic fluid is present. (B) Shorshows an area of ill-defined hypoechogenicity (long whitear, and a thick rim of surrounding anechoic fluid (short

Dislocation of the PTT is a traumatic occurrencerather than a degenerative process, caused by frankavulsion or stripping of the flexor retinaculum fromthe medial malleolus, allowing the tendon tosublux anteriorly [126]. The stripped or rupturedretinaculum and displaced PTT can be shown sono-graphically. Sometimes dynamic scanning in thetransverse plane during dorsiflexion and plantarflexion of the foot is necessary to show the unstableposition of the tendon.

The painful flexor hallucis longus tendon hasbeen termed dancer’s tendinitis [127], referring tothe posterior ankle pain experienced by ballerinasfrom repetitive hyperplantarflexion of the foot inthe en pointe position. This repetitive positioningcan eventually lead to stenosing tenosynovitis ofthe flexor hallucis longus as it passes behind thetalus. Typical patients with flexor hallucis longuspain are ballerinas [128], with the left foot morecommonly affected than the right because mostturns are to the right, requiring pivoting on theleft foot [127], but adults of any age and gendermay develop posterior ankle pain that is not alwaysassociated with sports [129,130].

Clinically, patients who have flexor hallucis lon-gus pain experience tenderness to palpation along

ort-axis sonographic image shows a normal echogenicrmal flexor digitorum longus tendon (black arrow). At-axis sonographic image of posterior tibial tendinosiste arrow), perhaps with a linear anechoic interstitialwhite arrow) in the tendon sheath.

Fig. 24. Short-axis sonographic image of posterior tib-ial tendon shows tendinosis and a linear hypoechoicinterstitial split tear (short white arrow). The tendonis surrounded by a markedly thickened tendon sheath(long white arrows).


the tendon at the posterior aspect of the ankle andpain throughout the entire range of motion [129],compared with patients who have posterior ankleimpingement caused by an os trigonum or largeposterior talar process, who experience pain onlyin plantar flexion [127,129]. Because the flexor hal-lucis longus courses under the sustentaculum taliand is adjacent to the posterior tibial nerve in thetarsal tunnel, patients may present with medialankle pain or heel pain mimicking plantar fasciitis[129]. Trigger-toe deformity of the hallux may bepresent because of nodular tenosynovitis prevent-ing smooth gliding of the tendon [130]. In a com-parison of two cohorts with flexor hallucis longustenosynovitis, Sammarco and Cooper [130] foundthat dancers experienced symptoms three timeslonger than nondancers and more than twice asmany interstitial tendon tears.

Sonographically, the affected tendon may looknormal, or may be thickened with heterogeneousechogenicity representing degeneration or interstitial

tears and have surrounding hypoechoic fluid fromtenosynovitis. The fluid may be focal, mimickinga cyst because of the focal stenosing tenosynovitis[130]. The tendon sheath may also be thickenedbecause of chronic scar (Fig. 26). Sonographicallyguided injection of the flexor hallucis longustendon sheath has recently been described [131],which has the advantage of directly visualizing thetendon compared with fluoroscopically guidedtenography.

Peroneal tendons

The peroneus longus and brevis tendons are locatedin the fibular groove in the posterior aspect of thelateral malleolus and are held in place by the supe-rior peroneal retinaculum. At the level of the lateralmalleolus, they are ensheathed in a common syno-vium but are invested in their own synovial sheathsdistal to the malleolus. They are dynamic stabilizersof the lateral side of the ankle and are pronators andplantar flexors of the foot; the peroneus brevis ten-don attaches to the base of the fifth metatarsal, andthe peroneus longus tendon crosses under thecuboid and attaches to the first metatarsal andmedial cuneiform.

These tendons are subject to longitudinal splittears and anterior subluxation, two conditionsthat are often associated. Trauma, such as an inver-sion injury, can rupture or strip the superior pero-neal retinaculum from its fibular attachment,allowing the tendons to sublux over the posterolat-eral margin of the fibula. The peroneus brevistendon is more often involved than the longus ten-don [132,133] because it is anterior in the fibulargroove; repetitive subluxation of the brevis tendon,pressed against the malleolus by the longus tendon,acts like a saw to cause a longitudinal split tear ofthe brevis. Transverse sonographic images at thelevel of the malleolus show the split tear as twosmall pieces of brevis tendon with the large pero-neus longus tendon in between (Fig. 27) [132].

Fig. 25. Longitudinal sono-graphic image of posteriortibial tendinosis showsa thickened tendon (whitearrows) and an area ofinterstitial degeneration(asterisk).

Fig. 26. Flexor hallucis longus tendinosis and scar. (A) Longitudinal sonographic image at the level of the hind-foot shows the flexor hallucis longus tendon (white arrows), with adjacent thick hypoechoic scar (black arrows).(B) Short axis sonographic power Doppler image shows the echogenic tendon (white arrow) surrounded by thickscar (black arrow). No hyperemia is present.

Miller610

Subluxation may be evident at rest, but occa-sionally dynamic scanning as the foot is dorsi-flexed and everted [132,133] is necessary to showthe peroneal subluxation. Correlation with clinicalsymptoms is important, however, because up to20% of asymptomatic people will exhibit peronealsubluxation [132]. Nontraumatic causes of sublux-ation include a hypoplastic fibular groove andcongenital absence of the superior peroneal reti-naculum [133].

Tears of the peroneus longus tendon are less com-mon than tears of the brevis tendon [134,135]. Thelongus usually tears at the level of the lateral mal-leolus but may rupture in the midfoot as it changes

Fig. 27. Peroneus brevis tendon split tear. (A) Short axis sona hypoechoic longitudinal split tear (round tail arrow) c(straight white arrows), with the intervening peroneus lT2-weighted MR image in this same patient shows the splwith the intervening peroneus longus tendon (black arro

direction at the peroneal groove of the cuboid tocross under the foot. This rupture can occur as a re-sult of inversion injury, strenuous activity in theunconditioned athlete, and systemic disease [136].Sonographic demonstration of a fragmented os per-oneum, with more than 6 mm of distraction of thefragments and hypoechoic in the fragment gap,indicates tendon rupture [136].

In a prospective study of sonography’s ability tocorrectly identify tears of the peroneal tendons,Grant and colleagues [137] reported 100% sensitiv-ity, 85% specificity, and 90% accuracy for diagnos-ing partial and complete tears, using surgery asthe gold standard.

ographic image through the peroneal tendons showsleaving the peroneus brevis tendon into two piecesongus tendon (black arrow). (B) Axial fat suppressedit pieces of the peroneus brevis tendon (white arrows)w).


Summary

The muscles and tendons of the lower extremity arecommonly injured as a result of sports, chronicoveruse, and systemic diseases. Sonography is wellsuited to evaluating these structures, providinghigh-resolution images and the dynamic ability toevaluate snapping tendons and fascial herniation,and guide percutaneous intervention.

References

[1] Leininger RE, Knox CL, Comstock RD. Epidemi-ology of 1.6 million pediatric soccer-relatedinjuries presenting to US emergency depart-ments from 1990 to 2003. Am J Sports Med2007;35(2):288–93.

[2] Junge A, Langevoort G, Pipe A, et al. Injuries inteam sport tournaments during the 2004 Olym-pic Games. Am J Sports Med 2006;34(4):565–76.

[3] Fernandez WG, Yard EE, Comstock RD. Epide-miology of lower extremity injuries amongU.S. high school athletes. Acad Emerg Med2007;14(7):641–5.

[4] Hootman JM, Dick R, Agel J. Epidemiology ofcollegiate injuries for 15 sports: summary andrecommendations for injury prevention initia-tives. J Athl Train 2007;42(2):311–9.

[5] Agel J, Evans TA, Dick R, et al. descriptive epide-miology of collegiate men’s soccer injuries:national collegiate athletic association injurysurveillance system, 1988–1989 through2002–2003. J Athl Train 2007;42(2):270–7.

[6] Brooks JHM, Fuller CW, Kemp SPT, et al. Epide-miology of injuries in English professionalrugby union: part 1 match injuries. Br J SportsMed 2005;39:757–66.

[7] Shankar PR, Fields SK, Collins CL, et al. Epide-miology of high school and collegiate footballinjuries in the United States, 2005–2006. Am JSports Med 2007;35(8):1295–303.

[8] Dick R, Ferrara MS, Agel J, et al. Descriptiveepidemiology of collegiate men’s football in-juries: National Collegiate Athletic AssociationInjury Surveillance System, 1988–1989 through2003–2004. J Athl Train 2007;42(2):221–33.

[9] Harringe ML, Renstrom P, Werner S. Injury inci-dence, mechanism and diagnosis in top-levelteam gym: a prospective study conducted overone season. Scand J Med Sci Sports 2007;17:115–9.

[10] Boesen MI, Boesen A, Koenig MJ, et al. Ultraso-nographic investigation of the Achilles tendonin elite badminton players using color Doppler.Am J Sports Med 2006;34(12):2013–22.

[11] Deitch JR, Starkey C, Walters SL, et al. Injury riskin professional basketball players: a comparisonof Women’s National Basketball Associationand National Basketball Association athletes.Am J Sports Med 2006;34(7):1077–83.

[12] Sallis RE, Jones K, Sunshine S, et al. Comparingsports injuries in men and women. Int J SportsMed 2001;22:420–3.

[13] Torriani M, Kattapuram SV. Musculoskeletalultrasound: an alternative imaging modalityfor sports-related injuries. Top Magn ResonImaging 2003;14(1):103–12.

[14] Peers KH, Lysens RJ. Patellar tendinopathy inathletes: current diagnostic and therapeutic rec-ommendations. Sports Med 2005;35(1):71–87.

[15] Rosenberg ZS, Cheung Y, Jahss MH, et al.Rupture of posterior tibial tendon: CT and MRimaging with surgical correlation. Radiology1988;169(1):229–35.

[16] Lohle PNM, Pulaet JBC, Coerkamp EG, et al.Nonpalpable rectus sheath hematoma clinicallymasquerading as appendicitis: US and CTdiagnosis. Abdom Imaging 1995;20:152–4.

[17] Wiggers RH, Rosekrans P. Ultrasound diagnosisof psoas hematoma. Diagn Imaging 1980;49:98–105.

[18] Maffulli N, So WS, Ahuja A, et al. Iliopsoas hae-matoma in adolescent Taekwondo player. KneeSurg Sports Traumatol Arthrosc 1996;3:230–3.

[19] Alanen A, Kormano M. Correlation of the echo-genicity and structure of clotted blood. J Ultra-sound Med 1985;4:421–5.

[20] Alanen A, Nummi P. Effect of motion on the so-nographic and magnetic resonance patterns ofageing blood. Acta Radiol Diagn 1986;4:455–8.

[21] Aspelin P, Ekberg O, Thorsson O, et al. Ultra-sound examination of soft tissue injury of thelower limb in athletes. Am J Sports Med 1992;20(5):601–3.

[22] Bunker TD, Esler CNA, Leach WJ. Rotator-cufftear of the hip. J Bone Joint Surg Br 1997;79:618–20.

[23] Pfirrmann CWA, Chung CB, Theumann NH,et al. Greater trochanter of the hip: attachmentof the abductor mechanism and a complex ofthree bursae—MR imaging and MR bursogra-phy in cadavers and MR imaging in asymptom-atic volunteers. Radiology 2001;221:469–77.

[24] Connell DA, Bass C, Sykes CJ, et al. Sono-graphic evaluation of gluteus medius and mini-mus tendinopathy. Eur Radiol 2003;13:1339–47.

[25] Cvitanic O, Henzie G, Skezas N, et al. MRI diag-nosis of tears of the hip abductor tendons (glu-teus medius and gluteus minimus). AJR Am JRoentgenol 2004;182:137–43.

[26] Chung CB, Robertson JE, Cho GJ, et al. Gluteusmedius tendon tears and avulsive injuries in el-derly women: imaging findings in six patients.AJR Am J Roentgenol 1999;173(2):351–3.

[27] Kingzett-Taylor A, Tirman PF, Feller J, et al. Ten-dinosis and tears of gluteus medius and mini-mus muscles as a cause of hip pain: MRimaging findings. AJR Am J Roentgenol 1999;173:1123–6.

[28] Kong A, Van der Vliet A, Zadow S. MRI and USof gluteal tendinopathy in greater trochanteric

Miller612

pain syndrome. Eur Radiol 2007;17(7):1772–83.

[29] Leonard MH. Trochanteric syndrome: calcare-ous and noncalcareous tendonitis and bursitisabout the trochanter major. J Am Med Assoc1958;168(2):175–7.

[30] Pelsser V, Cardinal E, Hobden R, et al. Extraar-ticular snapping hip: sonographic findings.AJR Am J Roentgenol 2001;176:67–73.

[31] Choi YS, Lee SM, Song BY, et al. Dynamicsonography of external snapping hip syndrome.J Ultrasound Med 2002;21:753–8.

[32] Janzen DL, Partridge E, Logan PM, et al. Thesnapping hip: clinical and imaging findings intransient subluxation of the iliopsoas tendon.Can Assoc Radiol J 1996;47(3):202–8.

[33] Schaberg JE, Harper MC, Allen WC. Thesnapping hip syndrome. Am J Sports Med1984;12(5):361–5.

[34] Khoury V, Cardinal E, Bureau NJ. Musculoskel-etal sonography: a dynamic tool for usual andunusual disorders. AJR Am J Roentgenol 2007;188:W63–73.

[35] Blankenbaker DG, De Smet AA, Keene JS.Sonography of the iliopsoas tendon and injec-tion of the iliopsoas bursa for diagnosis andmanagement of the painful snapping hip.Skeletal Radiol 2006;35:565–71.

[36] Wank R, Miller TT, Shapiro JF. Sonographicallyguided injection of anesthetic for iliopsoastendinopathy after total hip arthroplasty.J Clin Ultrasound 2004;32(7):354–7.

[37] Nicholas SJ, Tyler TF. Adductor muscle strainsin sport. Sports Med 2002;32(5):339–44.

[38] Emery CA, Meeuwisse WH, Powell JW. Groin andabdominal strain injuries in the National HockeyLeague. Clin J Sport Med 1999;9(3):151–6.

[39] Ekstrand J, Hilding J. The incidence and differ-ential diagnosis of acute groin injuries in malesoccer players. Scand J Med Sci Sports 1999;9:98–103.

[40] Orchard J, Seward H. Epidemiology of injuriesin the Australian Football League, seasons1997–2000. Br J Sports Med 2002;36:39–45.

[41] Maffey L, Emery C. What are the risk factors forgroin strain injury in sport? A systematic reviewof the literature. Sports Med 2007;37(10):881–94.

[42] Grote K, Lincoln TL, Gamble JG. Hip adductorinjury in competitive swimmers. Am J SportsMed 2004;32(1):104–8.

[43] Robinson P, Barron DA, Parsons W, et al.Adductor-related groin pain in athletes: correla-tion of MR imaging with clinical findings.Skeletal Radiol 2004;33:451–7.

[44] Kalebo J, Karlsson J, Sward L, et al. Ultrasonog-raphy of chronic tendon injuries in the groin.Am J Sports Med 1992;20(6):634–9.

[45] Goh LH, Chhem RK, Wang S, et al. Ultrasono-graphic features of an adductor longus tear:case report. Can Assoc Radiol J 2001;52(4):252–4.

[46] Weaver JS, Jacobson JA, Jamadar DA, et al.Sonographic findings of adductor insertionavulsion syndrome with magnetic resonanceimaging correlation. J Ultrasound Med 2003;22:403–7.

[47] Anderson MW, Kaplan PA, Dussault RG. Adduc-tor insertion avulsion syndrome (thigh splints):spectrum of MR imaging features. AJR Am JRoentgenol 2001;177(3):673–5.

[48] Sofka CM, Marx R, Adler RS. Utility of sonogra-phy for the diagnosis of adductor avulsioninjury (‘‘thigh splints’’). J Ultrasound Med2006;25(7):913–6.

[49] Bass CJ, Connell DA. Sonographic findings oftensor fascia lata tendinopathy: another causeof anterior groin pain. Skeletal Radiol 2002;31:143–8.

[50] Ilaslan H, Wenger DE, Shives TC, et al. Unilat-eral hypertrophy of tensor fascia lata: a softtissue tumor simulator. Skeletal Radiol 2003;32:628–32.

[51] Asinger DA, El-Khoury GY. Tensor fascia latamuscle tear: evaluation by MRI. Iowa Orthop J1998;18:146–9.

[52] Bianchi S, Martinoli C, Waser NP, et al. Centralaponeurosis tears of the rectus femoris:sonographic findings. Skeletal Radiol 2002;31:581–6.

[53] Robinson P, White LM. The Biomechanics andimaging of soccer injuries. Semin Musculoske-let Radiol 2005;9(4):397–420.

[54] Pisacano RM, Miller TT. Comparing sonogra-phy with MR imaging of apophyseal injuriesof the pelvis in four boys. AJR Am J Roentgenol2003;181(1):223–30.

[55] Woods C, Hawkins RD, Maltby S, et al. TheFootball Association Medical ResearchProgramme: an audit of injuries in professionalfootball—analysis of hamstring injuries. Br JSports Med 2004;38:36–41.

[56] Verrall GM, Slavotinek JP, Barnes PG, et al.Clinical risk factors for hamstring muscle straininjury: a prospective study with correlation ofinjury by magnetic resonance imaging. Br JSports Med 2001;35(6):435–9.

[57] Connell DA, Schneider-Kolsky ME, Hoving JL,et al. Longitudinal study comparing sono-graphic and MRI assessments of acute and heal-ing hamstring injuries. AJR Am J Roentgenol2004;183:975–84.

[58] Koulouris G, Connell D. Evaluation of thehamstring muscle complex following acuteinjury. Skeletal Radiol 2003;32(10):582–9.

[59] Slavotinek JP, Verrall GM, Fon GT. Hamstringinjury in athletes: using MR imagingmeasurements to compare extent of muscleinjury with amount of time lost from compe-tition. AJR Am J Roentgenol 2002;179(6):1621–8.

[60] Schneider-Kolsky ME, Hoving JL, Warren P,et al. A comparison between clinical assessmentand magnetic resonance imaging of acute


hamstring injuries. Am J Sports Med 2006;34(6):1008–15.

[61] Gibbs NJ, Cross TM, Cameron M, et al. Theaccuracy of MRI in predicting recovery andrecurrence of acute grade one hamstring musclestrains within the same season in AustralianRules football players. J Sci Med Sport 2004;7(2):248–58.

[62] Cross TM, Gibbs N, Houang MT, et al. Acutequadriceps muscle strains: magnetic resonanceimaging features and prognosis. Am J SportsMed 2004;32(3):710–9.

[63] Verrall GM, Slavotinek JP, Barnes PG, et al.Assessment of physical examination and mag-netic resonance imaging findings of hamstringinjury as predictors for recurrent injury.J Orthop Sports Phys Ther 2006;36(4):215–24.

[64] Ilan DI, Tejwani N, Keschner M, et al. Quadri-ceps tendon rupture. J Am Acad Orthop Surg2003;11(3):192–200.

[65] Bianchi S, Zwass A, Abdelwahab IF. Diagnosisof tears of the quadriceps tendon of the knee:value of sonography. AJR Am J Roentgenol1994;162:1137–40.

[66] La S, Fessell DP, Femino JE, et al. Sonography ofpartial-thickness quadriceps tendon tears withsurgical correlation. J Ultrasound Med 2003;22:1323–9.

[67] Schweitzer ME, Mitchell DG, Ehrlich SM. Thepatellar tendon: thickening, internal signalbuckling, and other MR variants. SkeletalRadiol 1993;22:411–6.

[68] Greis PE, Holmstrom MC, Lahav A. Surgicaltreatment options for patella tendon rupture,Part I: Acute. Orthopedics 2005;28(7):672–9.

[69] Lian OB, Engebretsen L, Bahr R. Prevalence ofjumper’s knee among elite athletes from differ-ent sports: a cross-sectional study. Am J SportsMed 2005;33:561–7.

[70] Khan KM, Bonar F, Desmond PM. Patellartendinosis (jumper’s knee): findings at histo-pathologic examination, US, and MR imaging.Victorian Institute of Sports Tendon StudyGroup. Radiology 1996;200:821–7.

[71] Gisslen K, Alfredson H. Neovascularisation andpain in jumper’s knee: a prospective clinical andsonographic study in elite junior volleyballplayers. Br J Sports Med 2005;39:423–8.

[72] Gisslen K, Gyulai C, Soderman K, et al. Highprevalence of jumper’s knee and sonographicchanges in Swedish elite junior volleyballplayers compared to matched controls. Br JSports Med 2005;39:298–301.

[73] Lian O, Holen KJ, Engebretsen L, et al. Rela-tionship between symptoms of jumper’sknee and the ultrasound characteristics ofthe patellar tendon among high level malevolleyball players. Scand J Med Sci Sports1996;6:291–6.

[74] Cook JL, Khan KM, Kiss ZS, et al. Patellartendinopathy in junior basketball players:a controlled clinical and ultrasonographic study

of 268 patellar tendons in players aged 14–18years. Scand J Med Sci Sports 2000;10:216–20.

[75] Cook JL, Khan KM, Kiss ZS, et al. Prospectiveimaging study of asymptomatic patellar tendin-opathy in elite junior basketball players. J Ultra-sound Med 2000;19:473–9.

[76] Khan KM, Cook JL, Kiss ZS, et al. Patellartendon ultrasonography and jumper’s knee infemale basketball players: a longitudinal study.Clin J Sport Med 1997;7(3):199–206.

[77] Gisslen K, Gyulai C, Nordstrom P, et al. Normalclinical and ultrasound findings indicate a lowrisk to sustain jumper’s knee patellar tendinop-athy: a longitudinal study on Swedish elitejunior volleyball players. Br J Sports Med2007;41:253–8.

[78] Cook JL, Malliaras P, De Luca J, et al. Neovascu-larization and pain in abnormal patellartendons of active jumping athletes. Clin J SportMed 2004;14(5):296–9.

[79] Cook JL, Malliaras P, De Luca J, et al. Vascularityand pain in the patellar tendon of adultjumping athletes: a 5 month longitudinal study.Br J Sports Med 2005;39(7):458–61.

[80] Demirag B, Ozturk C, Yazici Z, et al. Thepathophysiology of Osgood-Schlatter disease:a magnetic resonance investigation. J PediatrOrthop B 2004;13(6):379–82.

[81] Medlar RC, Lyne ED. Sinding-Larsen-Johanssondisease. Its etiology and natural history. J BoneJoint Surg Am 1978;60:1113–6.

[82] Rosenberg ZS, Kawelblum M, Cheung YY.Osgood-Schlatter lesion: fracture or tendinitis?Scintigraphic, CT, and MR imaging features.Radiology 1992;185:853–8.

[83] Malone AA, Dowd GS, Saifuddin A. Injuries ofthe posterior cruciate ligament and posterolat-eral corner of the knee. Injury 2006;37:485–501.

[84] Miller TT, Gladden P, Staron RB. Posterolateralstabilizers of the knee: anatomy and injurieswith MR imaging. AJR Am J Roentgenol 1997;169:1641–7.

[85] Harish S, O’Donnell P, Connell D, et al. Imag-ing of the posterolateral corner of the knee.Clin Radiol 2006;61:457–66.

[86] Stannard JP, Brown SL, Robinson JT, et al.Reconstruction of the posterolateral corner ofthe knee. Arthroscopy 2005;21:1051–9.

[87] Sekiya JK, Jacobson JA, Wojtys EM. Sonographicimaging of the posterolateral structures of theknee: findings in human cadavers. Arthroscopy2002;18(8):872–81.

[88] Yoon KH, Bae DK, Ha JH, et al. Anatomicreconstructive surgery for posterolateral insta-bility of the knee. Arthroscopy 2006;22:159–65.

[89] Delgado GJ, Chung CB, Lektrakul N, et al.Tennis leg: clinical US study of 141 patientsand anatomic investigation of four cadaverswith MR imaging and US. Radiology 2002;224:112–9.

Miller614

[90] Kwak HS, Han YM, Lee SY, et al. Diagnosis andfollow-up us evaluation of ruptures of themedial head of the gastrocnemius (‘‘tennisleg’’). Korean J Radiol 2006;7(3):193–8.

[91] Kwak HS, Lee KB, Han YM. Ruptures of themedial head of the gastrocnemius (‘‘tennisleg’’): clinical outcome and compression effect.Clin Imaging 2006;30(1):48–53.

[92] Bianchi S, Martinoli C, Abdelwahab IF, et al.Sonographic evaluation of tears of the gastroc-nemius medial head (‘‘tennis leg’’). J Ultra-sound Med 1998;17(3):157–62.

[93] Helms CA, Fritz RC, Garvin GJ. Plantarismuscle injury: evaluation with mr imaging.Radiology 1995;195(1):201–3.

[94] Leekam RN, Agur AM, McKee NH. Usingsonography to diagnose injury of plantarismuscles and tendons. AJR Am J Roentgenol1999;172(1):185–9.

[95] Kannus P, Jozsa L. Histopathological changespreceding spontaneous rupture of a tendon. Acontrolled study of 891 patients. J Bone JointSurg Am 1991;73:1507–25.

[96] Tallon C, Maffulli N, Ewen SWB. RupturedAchilles tendons are significantly more degener-ated than tendinopathic tendons. Med SciSports Exerc 2001;33(12):1983–90.

[97] Jarvinen TAH, Kannus P, Maffulli N, et al. Achil-les tendon disorders: etiology and epidemiol-ogy. Foot Ankle Clin 2005;10:255–66.

[98] Jarvinen TAH, Kannus P, Paavola M, et al. Achil-les tendon injuries. Curr Opin Rheumatol2001;13:150–5.

[99] Paavola M, Kannus P, Jarvinen TAH, et al. Achil-les tendinopathy. J Bone Joint Surg Am 2002;84:2062–76.

[100] Vora AM, Myerson MS, Oliva F, et al. Tendinop-athy of the main body of the Achilles tendon.Foot Ankle Clin N Am 2005;10:293–308.

[101] Paavola M, Kannus P, Paakkala T, et al. Long-term prognosis of patients with Achilles tendin-opathy: an observational 8-year follow-upstudy. Am J Sports Med 2000;28(5):634–42.

[102] Khan KM, Forster BB, Robinson J, et al. Areultrasound and magnetic resonance imagingof value in assessment of Achilles tendon disor-ders? A two year prospective study. Br J SportsMed 2003;37:149–53.

[103] Archambault JM, Wiley JP, Bray RC, et al. Cansonography predict the outcome in patientswith achillodynia? J Clin Ultrasound 1998;26(7):335–9.

[104] Nehrer S, Breitenseher M, Brodner W, et al.Clinical and sonographic evaluation of therisk of rupture in the Achilles tendon. ArchOrthop Trauma Surg 1997;116:14–8.

[105] Gibbon WW, Cooper JR, Radcliffe GS. Distribu-tion of sonographically detected tendon abnor-malities in patients with a clinical diagnosis ofchronic Achilles tendinosis. J Clin Ultrasound2000;28(2):61–6.

[106] Sayana MK, Maffulli N. Insertional Achillestendinopathy. Foot Ankle Clin N Am 2005;10:309–20.

[107] Paavola M, Paakkala T, Kannus P, et al. Ultraso-nography in the differential diagnosis ofAchilles tendon injuries and related disorders.A comparison between pre-operative ultraso-nography and surgical findings. Acta Radiol1998;39(6):612–9.

[108] Hartgerink P, Fessell DP, Jacobson JA, et al. Full-versus partial-thickness Achilles tendon tears:sonographic accuracy and characterization in26 cases with surgical correlation. Radiology2001;220:406–12.

[109] Bleakney RR, Tallon C, Wong JK, et al. Long-term ultrasonographic features of the Achillestendon after rupture. Clin J Sports Med 2002;12(5):273–8.

[110] Hollenberg GM, Adams MJ, Weinberg EP.Sonographic appearance of nonoperativelytreated Achilles tendon ruptures. Skeletal Radiol2000;29:259–64.

[111] Alfredson H, Ohberg L, Forsgren S. Is vasculo-neural ingrowth the cause of pain in chronicAchilles tendinosis? An investigation usingultrasonography and colour Doppler, immuno-histochemistry, and diagnostic injections. KneeSurg Sports Traumatol Arthrosc 2003;11:334–8.

[112] Ohberg L, Lorentzon R, Alfredson H. Neovascu-larization in Achilles tendons with painfultendinosis but not in normal tendons: an ultra-sonographic investigation. Knee Surg SportsTraumatol Arthrosc 2001;9:233–8.

[113] Ohberg L, Alfredson H. Sclerosing therapy inchronic Achilles tendon insertional pain-resultsof a pilot study. Knee Surg Sports TraumatolArthrosc 2003;11:339–43.

[114] Lind B, Ohberg L, Alfredson H. Sclerosingpolidocanol injections in mid-portion Achillestendinosis: remaining good clinical results anddecreased tendon thickness at 2-year follow-up. Knee Surg Sports Traumatol Arthrosc2006;14:1327–32.

[115] Boesen MI, Koenig MJ, Torp-Pedersen S, et al.Tendinopathy and Doppler activity: the vascularresponse of the Achilles tendon to exercise.Scand J Med Sci Sports 2006;16(6):463–9.

[116] Richards PJ, Win T, Jones PW. The distributionof microvascular response in Achilles tendon-opathy assessed by colour and power Doppler.Skeletal Radiol 2005;34:336–42.

[117] Peers KHE, Brys PPW, Lysens RJJ. Correlationbetween power Doppler ultrasonography andclinical severity in Achilles tendinopathy. IntOrthop 2003;27:180–3.

[118] Nazarian LN, Rawool NM, Martin CE, et al.Synovial fluid in the hindfoot and ankle:detection of amount and distribution with US.Radiology 1995;197:275–8.

[119] Schmidt WA, Schmidt H, Schicke B, et al.Standard reference values for musculoskeletal


ultrasonography. Ann Rheum Dis 2004;63:988–94.

[120] Gerling MC, Pfirrmann CWA, Farrookis S,et al. Posterior tibialis tendon tears compari-son of the diagnostic efficacy of magnetic res-onance imaging and ultrasonography for thedetection of surgically created longitudinaltears in cadavers. Invest Radiol 2003;38(1):51–6.

[121] Giza E, Cush G, Schon LC. The flexible flatfootin the adult. Foot Ankle Clin N Am 2007;12:251–71.

[122] Nallamshetty L, Nazarian LN, Schweitzer ME,et al. Evaluation of posterior tibial pathology:comparison of sonography and MR imaging.Skeletal Radiol 2005;34:375–80.

[123] Premkumar A, Perry MB, Dwyer AJ, et al.Sonography and MR imaging of posterior tibialtendinopathy. AJR Am J Roentgenol 2002;178:223–32.

[124] Lim PS, Schweitzer ME, Deely DM, et al.Posterior tibial tendon dysfunction: secondaryMR signs. Foot Ankle Int 1997;18(10):658–63.

[125] Deland JT, de Asla RJ, Sung I, et al. Posteriortibial tendon insufficiency: which ligamentsare involved? Foot Ankle Int 2005;26(6):427–35.

[126] Prato N, Abello E, Martinoli C, et al. Sonogra-phy of posterior tibialis tendon dislocation.J Ultrasound Med 2004;23:701–5.

[127] Hamilton WG. Tendonitis about the ankle jointin classical ballet dancers. Am J Sports Med1977;5(2):84–8.

[128] Michelson J, Dunn L. Tenosynovitis of theflexor hallucis longus: a clinical study of the

spectrum of presentation and treatment. FootAnkle Int 2005;26(4):291–303.

[129] Schulhofe SD, Oloff LM. Flexor hallucis longusdysfunction: an overview. Clin Podiatr MedSurg 2002;19:411–8.

[130] Sammarco GJ, Cooper PS. Flexor hallucislongus tendon injury in dancers and non-dancers. Foot Ankle Internat 1998;19(6):356–62.

[131] Mehdizade A, Adler RS. Sonographically guidedflexor hallucis longus tendon sheath injection.J Ultrasound Med 2007;26:233–7.

[132] Neustadter J, Raikin SM, Nazarian LN.Dynamic sonographic evaluation of peronealtendon subluxation. AJR Am J Roentgenol2004;183:985–8.

[133] Diaz GC, van Holsbeeck M, Jacobson JA. Longi-tudinal split of the peroneus longus andperoneus brevis tendons with disruption ofthe superior peroneal retinaculum. J Ultra-sound Med 1998;17:525–9.

[134] Dombek MF, Lamm BM, Saltrick K, et al.Peroneal tendon tears: a retrospective review.J Foot Ankle Surg 2003;42(5):250–8.

[135] Saxena A, Cassidy A. Peroneal tendon injuries:an evaluation of 49 tears in 41 patients. J FootAnkle Surg 2003;42(4):215–20.

[136] Brigido MK, Fessell DP, Jacobson JA, et al.Radiography and US of os peroneum fracturesand associated peroneal tendon injuries: initialexperience. Radiography 2005;237(1):235–41.

[137] Grant TH, Kelikian AS, Jereb SE, et al. Ultra-sound diagnosis of peroneal tendon tears. Asurgical correlation. J Bone Joint Surg Am2005;87(8):1788–94.



617

Ultrasound of Ligaments and BoneJoseph G. Craig, MB ChB

- Ligaments- General pathologic principles- Injury to the elbow ulnar collateral

ligament- Ulnar collateral ligament of the thumb- Ultrasound of the intrinsic and extrinsic

ligaments of the wrist- Medial collateral ligament of the knee- Lateral ligamentous complex of the ankle

- Medial ligamentous complex of the ankle- High ankle sprain- Evaluation of bone

FracturesTumorsOsteomyelitis

- Summary- Acknowledgements- References

Ultrasound of a ligament or ligamentous com-plex is less commonly requested by referring clini-cians than ultrasound of tendon or muscle, but itis useful for the radiologist to know the relevantanatomy and common pathology of ligaments.The ability of ultrasound to image in multipleplanes and improvements in both the hardwareand software of ultrasound machines allows excel-lent detail of normal and injured ligaments. Inparticular, the development of 12- to18-MHz trans-ducers has improved visualization of the smallerligaments.

Ultrasound of bone is rarely requested. The ini-tial work-up of any bone abnormality is a dedicatedradiographic series of the particular area in ques-tion. The radiologist should be aware, however,that incidental or relevant findings involving thebone may be made on ultrasound examination ofmusculoskeletal structures. In addition, ultrasoundcan be used to guide biopsies of bone and for aspi-ration in the setting of infection.

Ligaments

Ligaments can be classified as capsular, extracapsu-lar, or intra-articular [1]. Ligaments serve different

Radiology Department, Henry Ford Hospital, 2799 WestE-mail address: [email protected]


types of mechanical function and are designed toprevent excessive or abnormal movement [2]. Allligaments become taut at the normal limit ofsome particular movement [2].

Ligaments are composed of dense, regular con-nective tissues. There is more interweaving of colla-gen fibers than in tendons, giving ligaments anirregular histologic and sonographic appearance[3]. Ligaments typically are hyperechoic bands 2to 3 mm thick on ultrasound examination (Fig. 1).

General pathologic principles

Ligaments undergo partial or complete tear second-ary to excessive or extreme force, which often isacute but sometimes is chronic. The injured liga-ment initially may have been normal, or abnormalfrom chronic repetitive injury. In the experience ofthe author and his colleagues, once a ligament isinjured, it is unusual for it to revert to its normalcontour. Clinically, the ligamentous injury may behealed, and the patient may have no symptoms,but typically the previously injured ligament alwayshas an abnormal contour (Fig. 2) that results fromhealing by granulation tissue rather than the morespecialized ligamentous tissue.

Grand Boulevard, Detroit, MI 48202, USA




Fig. 1. Normal anterior talofibular ligament of the lat-eral ankle. Note the normal hyperechoic structure ofthe ligament (arrows) running between the anteriortalus (Tal) and the anterior fibula (Fib).

Craig618

Injury to the elbow ulnar collateral ligament

The medial collateral ligamentous complex of theelbow is comprised of three parts, the anteriorband, an oblique or transverse band, and a posteriorband (Fig. 3) [2]. The anterior band extends fromthe undersurface of the medial epicondyle to thesublime tubercle on the medial aspect of the prox-imal ulna, just medial to the coracoid process.The posterior band runs from the head of the me-dial epicondyle to the medial margin of the olecra-non. The transverse or oblique band runs across themedial olecranon connecting the anterior and pos-terior bands. The posterior band contributes to thefloor of the cubital tunnel.

Fig. 2. Injured ligament. (A) Complete tear of the anteriorbelow the medial epicondyle (Med Epic). Note the disruparrows). The most distal part of the ligament is still inta(ST). (B) Follow-up examination 2 years later. Althoughremains abnormal. There now is less hypoechogenicity, alabnormal with loss of the normal regular hyperechoic starrows). The distal part of the ligament looks more norsublime tubercle.

The primary restraint to valgus force at the elbowis the anterior band of the ulnar collateral ligament(UCL) [4,5]. The ligament is at risk in throwing ath-letes, particularly baseball pitchers and javelinthrowers. The injury may be acute but is more com-monly caused by chronic repetitive microtraumafrom recurrent valgus force.

The anterior band of the UCL is visualized clearlyon ultrasound and is examined in the coronalplane. The normal ligament has a triangular appear-ance, arising from the undersurface of medial epi-condyle and inserting on the sublime tubercle(Fig. 4). The normal ligament typically is hypere-choic. The anatomy of the normal anterior bandof the UCL on ultrasound has been correlatedwith a cadaver study [6]. The anterior band isdefined on ultrasound by its hyperechoic and com-pact fibrillar appearance. The proximal aspect of theUCL can vary. A distinct bundle of uniform thick-ness may extend from the apex of the medial epi-condyle with deeper hyperechoic tissue containingfat at the undersurface of the medial epicondyle.The second appearance is of a broad attachmentof the proximal ligament to the undersurface ofthe medial epicondyle.

A full-thickness tear may occur either proximallyor in the midsubstance of the ligament. On ultra-sound there is thickening and discontinuity of theligament with edema in the acute phase (Fig. 5).In the acute setting there also is tenderness on ultra-sound examination over the anterior band of theUCL. Other findings reported in full-thickness tear

band of the ulnar collateral ligament proximally, justted, swollen proximal portion of the ligament (shortct (long arrow) and attaches to the sublime tuberclethe patient’s symptoms have resolved, the ligamentthough the contour of the proximal ligament remainsructure and some residual proximal deformity (smallmal (large arrow). Med Epic, medial epicondyle; ST,

Fig. 3. The three bands of theulnar collateral ligament.

Ultrasound of Ligaments and Bone 619

of the anterior band include an anechoic fluid inthe gap of the tear and nonvisualization of the lig-ament with heterogeneous echogenicity in theexpected location of the ligament [5]. In children,the medial epicondyle may be avulsed with sono-graphic demonstration of the avulsed echogenicbony fragment [5].

Fig. 4. (A) Positioning of the transducer on the medial sideulnar collateral ligament (UCL). (B) The normal ulnar collundersurface of the medial epicondyle to the sublime tubemore fibrillar band (long arrows) and the more hyperecholayer is more variable and may represent either ligament oepicondyle.

A partial-thickness tear of the anterior band ofthe UCL classically is described as detachment ofthe deep fibers from the coronoid process. Onarthrography a T sign is described with undercuttingof the attachment of the anterior band on the sub-lime tubercle [7]. On sonography there is no T sign,because no contrast or saline is injected, but

of the elbow for evaluation of the anterior band of theateral ligament (UCL) of the elbow extends from thercle (ST) on the medial proximal ulna. Note the thinner,ic tissue deep to this band (short arrows). This deeper

r fibrofatty tissue. FLT, flexor tendon; Med Epic, medial

Fig. 5. Acute rupture of the anterior band of the ul-nar collateral ligament in a baseball pitcher. The en-tire ligament is swollen (small arrows), and there iscomplete rupture proximally (large arrow). Notealso the redundancy of the ligament secondary tothe complete tear. A small amount of fluid is seenin the medial elbow joint (arrowhead). Comparethe appearances with the normal ligament inFig. 4B. Med Epic, medial epicondyle; ST, sublimetubercle.

Craig620

thickening and some irregularity of the ligamentwithout focal disruption is typical (Fig. 6).

One of the advantages of examining the anteriorband by ultrasound is the ability to apply valgusstress and to assess opening of the medial elbowjoint. Sasaki and colleagues [8] described the useof ultrasound with stress to assess the anteriorband of the UCL in 50 college baseball players.

Fig. 6. (A) Partial tear of the anterior band of the ulnar coling of the anterior band (small arrows) and the wideningEpic, medial epicondyle; ST, sublime tubercle. (B) Correspimage. Note the slight thickening of the anterior band pattachment of the distal anterior band on the sublime tu

Gravity stress was applied with the elbow in 90�

of flexion, and ultrasonography of the medial as-pect of the elbow was performed. The medial jointspace was significantly wider on the throwing sidethan on the contralateral side (2.7 mm versus 1.6mm), and the proximal part of the ulna was shiftedsignificantly laterally on the throwing side.

Dynamic ultrasound of the anterior band of theUCL also has been described in asymptomaticmajor league baseball pitchers [9]. In this series,the anterior band of the UCL in the pitching elbowwas compared with the nonpitching elbow. Whenvalgus stress was applied, the medial joint spacewidth at the elbow was significantly wider in thepitching elbow than in the nonpitching elbow.Other findings included hypoechoic foci in theanterior band and calcifications in the pitchingelbow. Dynamic examination of the anterior bandof the UCL therefore is possible, and the authorand colleagues routinely use it clinically (Fig. 7).

Ulnar collateral ligament of the thumb

The normal radial collateral ligaments and UCLsare visualized easily with high-frequency trans-ducers as hyperechoic bands. On ultrasound, theligament is examined primarily in the longitudinal(coronal) and transverse planes. A high-frequencytransducer is preferred. The normal ligament ishyperechoic and runs between the ulnar (medial)

lateral ligament. Note the irregularity and slight swell-of the medial elbow joint space (large arrow). Med

onding MR coronal gradient T1-weighted arthrogramroximally (large arrow) and the undercutting of thebercle (small arrow) forming the T sign.

Fig. 7. Dynamic examination of injured anterior bandof the ulnar collateral ligament. Valgus stress isapplied to an elbow in which there is a completetear of the proximal ulnar collateral ligament (largearrow). Note the widening of the medial joint space(small arrow) to 4 mm (arrowheads). Note also thefluid in the medial joint. Med Epic, medial epicon-dyle; ST, sublime tubercle; T, trochlea.


first metacarpal neck and the base of the proximalphalanx (Figs. 8 and 9).

Injury to the UCL of the thumb has been referredto as ‘‘gamekeepers thumb’’ or more recently as‘‘skiers thumb’’ [10]. The injury was first describedby Campbell [11], who documented the ligamentousdamage in gamekeepers engaged in the killing ofrabbits. In 24 gamekeepers, only 4 failed to show lax-ity of the UCL on the ulnar side. The injury may occurafter a single episode of trauma or after chronicrepetitive trauma. Damage to the UCL is caused byhyperabduction of the metacarpophalangeal jointaccompanied by varying degrees of hyperextension.The injury may progress to chronic pain and osteo-arthrosis. On radiographic examination, a smallavulsed fragment of bone may be seen from thebase of the ulnar aspect of the proximal phalanx.

Injury to the UCL results in swelling and discon-tinuity of the ligament. Swelling is seen as a hypoe-choic area. Discontinuity is seen as interruption ofthe ligament (Fig. 10). An important anatomiclandmark to consider in injury to the UCL is theadductor pollicis muscle and its aponeurosis. Theanatomy is complex. The adductor aponeurosisinserts into the ulnar sesamoid, the base of theproximal phalanx, and the extensor apparatus[10]. The UCL is covered by this aponeurosis, andthe position of the injured UCL in relation to theaponeurosis is an important clinical findingbecause it influences surgical management of theinjury. Usually, when the UCL is torn, the tornend is from the proximal phalanx of the thumb[12]. If the retracted stump of the torn tendon

herniates superficial to the adductor aponeurosis,the injury is referred to as the ‘‘Stener lesion,’’(Fig. 11) after Stener [13], who first described dis-placement of a ruptured UCL in 1962. The ligamentis unlikely to heal because of the interposed apo-neurosis, and surgical intervention is indicated.The Stener lesion, if untreated, may cause chronicinstability and osteoarthrosis of the joint [10].

The reported reliability of ultrasound in identify-ing the adductor aponeurosis has been variable.Hergan and Mittler [10] found the adductor apo-neurosis is demarcated from the adjacent subcuta-neous fat as a hypoechoic band running from theneck of the metacarpal to the base of the proximalphalanx. Hoglund and colleagues [14] also wereable to identify the adductor aponeurosis and cor-rectly diagnosed the Stener lesion by ultrasoundin 32 of 39 patients. Jones and colleagues [15],however, found it extremely difficult to identifythe adductor aponeurosis reliably. The experienceof the author and colleagues is that, even withhigh-resolution ultrasound probes, identificationof the adductor aponeurosis sometimes is difficultafter injury. Furthermore, the echogenicity ofthe normal aponeurosis can be variable. When theultrasound beam is directly at a right angle to theaponeurosis, it is hyperechoic; when the angle ofthe ultrasound beam is oblique, the aponeurosisis more hypoechoic (see Fig. 9B).

Using high-frequency ultrasound, Noszian andcolleagues [12] examined 69 patients suspected ofhaving UCL ruptures. The ligament was examinedin the longitudinal plane, and three types of liga-ments were seen at sonography: normal (grade 1),thickened (grade 2), and retracted (grade 3). Itwas noted that complete differentiation betweenthe UCL and the adductor aponeurosis often couldnot be achieved. Grade 2 ligaments were markedlythickened but were in a normal position. Surgicalcorrelation showed that the ultrasound studiescould not differentiate a torn ligament from a non-torn ligament consistently. In grade 3 ligaments, thedisplaced UCL was seen as a circumscribed hypoe-choic mass adjacent to the metacarpal head withno continuity with the proximal phalanx demon-strated. Some of the displaced ligaments wereseen as more bandlike structures. Displacement ofthe UCL was diagnosed correctly in 33 of 39 patientswho went to surgery. A thickened but intact liga-ment was found in five of the six patients whohad false-positive findings, and rupture in situ wasseen in one patient.

Bianchi and Martinoli [16] emphasize the impor-tance of the longitudinal plane in identifyinga rounded mass representing the displaced UCLand absence of an attachment to the base of theproximal phalanx. The author and colleagues also

Fig. 8. (A) Normal ulnar collateral ligament of the thumb. (B) Positioning of transducer to evaluate the ulnarcollateral ligament of the thumb, longitudinal view. (C) Normal ulnar collateral ligament of the thumb. Notethe normal predominantly hyperechoic appearance (arrows) of the ligament running between the first metacar-pal and the proximal phalanx on the medial side.

Craig622

Fig. 9. (A) Positioning of the transducer for the transverse image of the ulnar collateral ligament of the thumb.(B) Transverse image of the normal ulnar collateral ligament. Note the hyperechoic proximal ulnar collateralligament adjacent to the base of the first metacarpal (short arrows), the adductor pollicis (ADD) (long arrows),and its aponeurosis (arrowheads). Note also the change in appearance of the adductor aponeurosis. When it isat right angles to the ultrasound beam, it is hyperechoic. When it is slightly oblique to the beam, it is more hy-poechoic. DI, first dorsal interosseous muscle.

Fig. 10. (Left view) Coronal or long-axis image ofa tear of the ulnar collateral ligament of the rightthumb. Note the swollen hyperechoic ligamentfollowing acute trauma (arrows). Also note the smallhyperechoic focus (arrowhead) consistent with a tinyavulsed piece of bone. The ligament is not displacedor retracted and, although markedly swollen, is stillin its normal position. (Right view) The normalasymptomatic left thumb. Note the normal ulnar col-lateral ligament (arrows). Prox Phalanx, proximalphalanx; MC1, first metacarpal.


have found the longitudinal plane very useful foridentifying the retracted ligament and emphasizeits importance (see Fig. 11C, D).

In summary, the UCL can be visualized easilywith high-frequency transducers. If there is any un-certainty about whether the UCL is normal, it iseasy to compare it with the asymptomatic oppositeligament. Some cases of Stener injury are extremelydifficult. If the injured ligament parallels its normalcourse and has an attachment to the proximal pha-lanx, a Stener lesion is unlikely. The ligament maybe torn and undisplaced, partially torn, or even se-verely contused. It can be difficult at times to differ-entiate confidently among these injuries. Theadductor pollicis aponeurosis can be difficult tovisualize in the acutely injured thumb. If theinjured ligament is retracted, rounded, and has noattachment to the proximal phalanx, it most likelyis sitting above the aponeurosis, consistent withthe Stener injury.

Fig. 11. Injury to the ulnar collateral ligament, Stener lesion. (A) Diagram of the Stener lesion. Note the retractedulnar collateral ligament. (B) Lateral view of the Stener lesion. (C) Positioning of transducer for the long-axisview. (D) The long-axis view of the medial aspect of the proximal thumb shows a retracted bunched up ulnarcollateral ligament (arrows) adjacent to the first metacarpal head. Compare this long-axis view with Fig. 10.PP, proximal phalanx. (E) Positioning of transducer for transverse view. (F) The transverse image shows thatthe mass (straight arrows) sits above the adductor pollicis (Add pollicis) aponeurosis (arrowheads). DI, first dorsalinterosseous muscle.

Craig624

Fig. 11 (continued )


Fig. 13. Normal dorsal scapholunate ligament. Notethe normal hyperechoic triangular dorsal scapholu-nate ligament (arrows). Superficial to the ligamentare the extrinsic wrist ligaments, primarily the dorsalradiotriquetral ligament (ext l) and superficial tothese the common extensor tendons (ext t). L, lunate;S, scaphoid; T, triquetrum.

Craig626

Ultrasound of the intrinsic and extrinsicligaments of the wrist

Ultrasound has been used to evaluate the intrinsicand extrinsic ligaments of the wrist [17–19]. Theligament most closely studied has been the dorsalaspect of the scapholunate ligament, and the dorsallunotriquetral ligament also has been examined.The extrinsic ligaments of the wrist have been par-tially or completely identified to variable degrees.

The scapholunate and lunotriquetral ligamentsare U-shaped structures having ventral, central,and dorsal components [18]. The dorsal and ven-tral portions are thicker and are composed of colla-gen fibers, whereas the central portion is composedof fibrocartilage [19]. The dorsal scapholunate liga-ment can be identified reliably (Figs. 12 and 13).The initial landmark to use in locating the dorsalaspect of the scapholunate joint is Lister’s tubercle[18]. The characteristic V-shaped articulationbetween the scaphoid and lunate bones is distalto Lister’s tubercle. Care should be taken not to mis-take the dorsal radiotriquetral ligament for thescapholunate ligament. With a high-frequency

Fig. 12. Carpus with dorsal scapholunate and lunotri-quetral ligaments with positioning of the high-frequency transducer over the scapholunateligament.

transducer, abnormality of the dorsal scapholunateligament includes loss of the normal echogenicappearance, disruption or absence of the normalligament, or fluid across a gap in the ligament[18]. The dorsal lunate triquetral ligament alsocan be identified by moving the transducer medi-ally after identifying the scapholunate ligament(Fig. 14). Abnormality of this ligament can bedetermined by the loss of the normal hyperechoicfibrillar pattern.

A major problem with ultrasound currently isthat the central or most proximal portion of theligament, which typically is also the thinnest part,cannot be identified, and the ventral or palmar por-tions of the ligaments also are extremely difficult tovisualize. This difficulty in visualization also isa problem when correlating arthrography or MR ar-thrography with ultrasound. The tear or tears seenon arthrography or MR arthrography may be ina different portion of the ligament than the tearseen at ultrasound.

Fig. 14. Normal dorsal lunotriquetral ligament. Notethe hyperechoic lunotriquetral ligament (arrows).Ext t, extensor tendons; L, lunate; T, triquetrum; U,ulna.

Fig. 15. Normal medial collateral ligament. (A) Normal anatomy. Sagittal view of the normal medial collateralligament of the knee. (B) Positioning of the transducer. (C) Normal ultrasound appearance. Note the hypere-choic appearance of the ligament (arrows) attaching to the femur and tibia. (D) Coned-down view of the medialcollateral ligament showing the trilaminar appearance. Note the hypoechoic slit (arrows) between the superfi-cial (S) and deep (D) parts of the ligament representing either a bursa or fibrofatty tissue. MM, medial meniscus.


Craig628

At present, the dorsal scapholunate ligament andusually the lunotriquetral dorsal ligament can beidentified reliably on ultrasound, and interruptionof these ligaments may be defined. Identificationof the other carpal ligaments is less reliable.

Medial collateral ligament of the knee

The medial collateral ligament (MCL) of the knee isvisualized clearly on ultrasound examination, as arethe major components of the lateral ligamentouscomplex, the iliotibial band, the popliteal tendon,the lateral collateral ligament proper, and the bicepsfemoris tendon. The normal MCL is seen on ultra-sound as a trilaminar structure: two hyperechoiclayers separated by a hyperechoic zone (Fig. 15)[3]. The hyperreflective bands represent the superfi-cial and deep parts of the MCL with the hypoechoicarea representing loose connective tissue [3]. Thewidth of the normal MCL adjacent to the concavityof the medial surface of the medial femoral condyleis 3 to 6 mm, � 0.5 mm [3].

Injury to the MCL frequently is associated withinjury to other structures, particularly the anteriorcruciate ligament and the menisci. In this setting,a MR examination is preferred. A pure valgus stresscan cause isolated MCL rupture. Acute rupture ofthe MCL is seen as disruption of the normal bandsof the MCL, frequently with a large hematoma.Most commonly the MCL ruptures from its attach-ment to the medial femoral condyle (Fig. 16).

Fig. 16. (A) Acute rupture of the medial collateral menimixed echogenicity including hypoechoic areas. Note alsarrows). Compare the appearance with Fig. 15C. (B) Imexamination of the asymptomatic left femur. Note again(large arrows) and compare it with the asymptomatic lef

Partial rupture of the MCL results in thickening ofthe ligament [3].

Chronic rupture of the MCL is characterized bythickening and disruption of the ligament(Fig. 17). The trilaminar appearance of the MCLis no longer visualized. The thickening is morecommon adjacent to the medial femoral condyle.

Lateral ligamentous complex of the ankle

The lateral ligamentous complex of the ankle com-prises the anterior and posterior talofibular liga-ments and the calcaneofibular ligament (Fig. 18).The lateral ligamentous complex can be evaluatedwith ultrasound [20–22]. The lateral ligamentmost reliably identified is the anterior talofibularligament (Fig. 19). The transducer is placed ante-rior to the tip of the fibula in an almost transverseplane. The calcaneofibular and posterior talofibularligaments can be identified but are technically moredifficult to visualize. Because these ligaments slopeaway from the transducer, part of the ligamentfrequently shows anisotropy; this finding shouldnot be mistaken for pathology (see Fig. 19).

Most lateral ligamentous injuries occur frominversion [23]. Injury most commonly involvesthe anterior talofibular ligament and the calcaneo-fibular ligaments. The anterior and posteriortalofibular ligaments run predominantly in thetransverse or axial plane; the calcaneofibular liga-ment runs predominantly in the coronal obliqueplane. The anterior talofibular ligament is involved

scus. Note the swollen ligament (large arrows) witho mild extrusion of the medial meniscus (MM) (shortaging of the proximal right femur and comparisonthe swollen right proximal medial collateral meniscust medial collateral meniscus (small arrow).

Fig. 17. (A) Chronic rupture of the medial collateral meniscus. Long-axis view of the medial collateral meniscusshows an enlarged ligament with mixed echogenicity (large arrows). Note also the linear echogenic line adja-cent to the proximal femur (small arrow). (B) Panoramic longitudinal view of the medial collateral meniscusshows an enlarged mixed echogenicity ligament (large arrows). Note again the linear echogenic line adjacentto the proximal medial condyle (small arrow). (C)The anteroposterior radiograph shows a linear opaque line(arrow) consistent with Pellegrini-Stieda calcification/ossification, corresponding with the small hyperechoicline noted in panels A and B.

Fig. 18. Normal lateral ligamentous structures of theankle. Lateral view of the ankle shows the anteriortalofibular ligament, the calcaneofibular ligament,the posterior talofibular ligament, and the anteriorand posterior tibiofibular ligaments.


in 70% of the ankle ligament ruptures, and theanterior talofibular and calcaneofibular ligamentsare involved in 20% of cases, [3]. In 7% to 16%of patients, injury to the lateral ligamentous com-plex is associated with an avulsion fracture. Thefrequency is higher in patients over age 50 years(27%) [23]. Tear of the posterior talofibular liga-ment is uncommon. Sonographically, a tear is char-acterized by thickening, loss of fibrillar pattern, anddiscontinuity of the ligament (Fig. 20).

Medial ligamentous complex of the ankle

The deltoid ligament is the strong ligament on themedial side of the ankle and has navicular, talar,and calcaneal attachments. It is composed of two

Fig. 19. (A) Position of the transducer for the anterior talofibular ligament. (B) Normal anterior talofibular lig-ament (arrows). Note the hyperechoic appearance of the ligament. Notice also the small effusion in the ankle(arrowhead). (C) Calcaneofibular ligament. Note that the proximal portion of the ligament is hypoechoic fromanisotropy (short arrows) because it is not at right angles to the ultrasound beam. The more distal portion of theligament (long arrows) is visualized, however. Calc, calcaneus; lat mal, lateral malleolus.

Fig. 20. Acute tear of the anterior talofibular liga-ment. Note the marked thickening of the ligament(arrows) and also some hyperemia around the liga-ment. There is also a small effusion in the ankle joint(arrowhead). Compare with the normal ligament inFig. 19B. Fib, fibula.

Craig630

layers, superficial and deep. Injuries to the deltoidligament account for approximately 15% of liga-mentous ankle trauma and usually are associatedwith injuries to the lateral collateral ligamentouscomplex, the distal tibiofibular syndesmosis,and malleolar fractures [24]. Isolated injury to thedeltoid ligament is uncommon. On ultrasound,the attachments to navicular, talus, and calcaneuscan be visualized (Fig. 21). Injury to the ligamentis characterized by swelling, loss of normal fibrillarcontour and discontinuity (Fig. 22).

High ankle sprain

High ankle sprain refers to injury of the distal tibio-fibular syndesmosis. The distal tibiofibular

Fig. 21. (A) Normal deltoid ligament. Note the navicular, talar, and calcaneal components. (B) Positioning of thetransducer for the anterior tibiotalar portion of the ligament. (C) Normal anterior tibiotalar deltoid ligament(arrows). Note the triangular echogenic appearance of the ligament. (D) Normal tibiocalcaneal portion of thedeltoid ligament. Note the hyperechoic tibiocalcaneal ligament running from the medial malleolus to thesustentaculum tali (arrows). Note also the small effusion in the ankle (arrowhead). MM, medial malleolus;SST, sustentaculum tali.

Fig. 22. Acute rupture of the deltoid ligament. (A) Anteroposterior radiograph in a patient who had sustaineda lateral malleolar fracture shows marginal widening of the medial clear space (arrow). The clinical question waswhether the deltoid ligament was ruptured. (B) Coronal image through the anterior tibiotalar part of theligament shows diffuse swelling and loss of the normal echogenicity (arrows) consistent with rupture. The otherportions of the ligament had a similar appearance. Compare the appearance with Fig. 21C. MM, medialmalleolus.


Fig. 23. (A) Positioning of the transducer for the anterior tibiofibular ligament. (B) Normal ultrasound appear-ance of the anterior tibiofibular ligament (arrows). FIB, fibula; TIB, tibia.

Craig632

articulation is stabilized by the anterior and poste-rior tibiofibular ligaments and by the interosseousligament. Individuals who participate in skiing,football, soccer, and other turf sports are at greatestrisk for injury to this ligament [25].

Fig. 24. Injury to the anterior tibiofibular ligament. (A) Teon ultrasound examination. Note the cleft (arrows) withinaxial fast fat-suppressed T2-weighted MR examination thdisruption of the ligament and widening of the anterior

Three mechanisms of injury have been proposed[25]: external rotation of the foot, eversion of thetalus within the ankle mortise, and excessivedorsiflexion. The mechanism of injury is differentfrom typical ankle sprains. Clinically, patients

ar of the anterior tibiofibular ligament demonstratedthe ligament. FIB, fibula; TIB, tibia. (B) Correspondingrough the level of the distal tibia and fibula showsdistal tibiofibular joint (arrow).

Fig. 25. Fracture of the greater tuberosity of the humerus. (A) Long-axis ultrasound section through the supra-spinatus tendon shows an intact tendon attaching to the greater tuberosity. Note, however, there is a step-off(arrows) of the tuberosity. GT, greater tuberosity; SST, supraspinatus tendon; H, humeral head. (B) Short-axisview through the supraspinatus also shows the step-off deformity (arrows). Note again the supraspinatus ten-don is intact. GT, greater tuberosity; SST, supraspinatus tendon. (C) Follow-up anteroposterior radiograph of theright shoulder shows a healing greater tuberosity fracture (arrow).


Fig. 26. Biopsy of bone. (A) Axial CT section through the proximal chest in a patient who has lung and prostatecarcinoma. Note destruction of the inferior scapula (large arrow) consistent with metastatic disease. Note alsothe primary carcinoma of lung (small arrow). Biopsy was requested to determine the nature of the metastaticlesion. (B) Axial ultrasound image through the tip of the scapula shows destruction of the bone and a soft tissuemass (arrows). There is increased vascularity in and around the lesion. (C) Ultrasound-guided biopsy wasperformed with placement of a spinal needle (arrows) into the lesion. The pathology showed metastatic non-small cell carcinoma of lung.

Craig634


have pain over the anterior tibiofibular ligament,pain with external rotation of the foot, and painwith dorsiflexion. Radiographs only occasionallyshow widening of the distal tibiofibularsyndesmosis.

The anterior tibiofibular ligament can bedemonstrated reliably on ultrasound examination(Fig. 23). An injured anterior tibiofibular ligamentis characterized by widening of the syndesmosisanteriorly, a cleft, and discontinuity of the ligament(Fig. 24). Distraction at the syndesmosis can bemeasured and compared with the normal side.The injury frequently has an associated effusionwithin the ankle joint.

Evaluation of bone

Primary evaluation of bone is an uncommon use ofultrasound, but a bone abnormality may be identi-fied incidentally or in association with the tissueabnormality being evaluated.

Fractures

Evaluation of all fractures requires an initial high-quality radiographic evaluation. Often, however,radiographs have not been taken or are unavailable.Fractures may be seen incidentally on ultrasound.A common example is the occult fracture of thegreater tuberosity found after trauma when evaluat-ing for possible rotator cuff tear (Fig. 25). It is

Fig. 27. Osteomyelitis on ultrasound. Acute osteomyelitis(A) Transverse ultrasound image shows a diffuse hypoechcent to the femur (F). Note also the break in the medial fcloaca (large arrow). (B) Transverse fast fat-suppressed Tshows the circular medial collection (long arrows) and inmusculature. The bone destruction/cloaca is not as wellpockets of air in the abscess and medullary cavities secoCultures grew Bacteroides fragilis.

important to be aware this diagnosis, because theclinical management of greater tuberosity fractureis very different from that of rotator cuff tear.

Tumors

When evaluating an extremity for possible muscleor tendinous abnormality, an abnormality of theadjacent bone occasionally is found. This abnor-mality may be a primary or secondary tumor, andit is important to have a radiographic evaluationof the area in question before obtaining an ultra-sound. Ultrasound also may be used to guide biop-sies of primary or secondary bone tumors (Fig. 26).

Osteomyelitis

Ultrasound can evaluate osteomyelitis both in chil-dren and adults [26–35]. Typically, in long bone os-teomyelitis in children, there is periosteal reactionwith subperiosteal pus that can be aspirated. Inadults, deformity and/or destruction of the bonecan be evaluated (Fig. 27). Ultrasound also is excel-lent in assessing acute or chronic septic arthritis/osteomyelitis. Fluid in the suspected joint can beaspirated. Whether fluid is infected in the settingof sepsis cannot be determined by ultrasound crite-ria, and aspiration and laboratory analysis arerequired (Fig. 28) [35]. With chronic septic arthri-tis/osteomyelitis, there is frequently synovial andgranulation tissue proliferation without a large

of the femur in a patient who has Gaucher’s disease.oic area with an anechoic center (short arrows) adja-emur cortex consistent with destruction of the femur/2-weighted MR examination through the same areacreased signal with the medullary cavity and anteriordemonstrated as on the ultrasound. Note also smallndary to recent surgical debridement (short arrows).

Fig. 28. Septic arthritis/osteomyelitis. (A) Anteroposterior radiograph of the left hip shows severe loss of jointspace and subchondral changes (arrows). (B) Long-axis ultrasound of the left hip shows mild distension of theanterior capsule (large arrows) and hyperechoic material within the joint (small arrow). The hip was aspiratedunder ultrasound guidance and grew Staphylococcus aureus. The hip joint subsequently was opened surgicallyand washed out. FH, femoral head. (C) Inversion recovery MR image of the pelvis and hips shows the loss of lefthip joint space, an effusion in the left hip joint, and extensive diffuse edema within both the femoral head andacetabulum (arrows). There also is edema in the soft tissues around the hip joint.

Craig636

amount of fluid; in that case, ultrasound is useful inlocalizing the fluid for aspiration.

Summary

The development of high-frequency transducersallows excellent visualization of ligaments. Normalligaments are hyperechoic and are 2 to 3 mm inwidth. Ligamentous tear may occur acutely orchronically. Tear is characterized by swelling ofthe ligament, discontinuity, redundancy, and retrac-tion. Ultrasound evaluation of bone is rarelyrequested, but the radiologist should be aware ofincidental findings in bone, particularly fracture.In the setting of biopsy and osteomyelitis, ultra-sound can be very useful.

Acknowledgements

The author thanks Jay Knipstein for the drawings.

References

[1] Gardner E, Gray DJ, O’Rahilly R. Joints. In: Anat-omy, a regional study of human structure. 4thedition. Philadelphia: WB Saunders; 1975. p.17–22.

[2] Warwick R, Williams PL, editors. Arthrology. In:Gray’s Anatomy. 35th edition. Edinburgh (UK):Longman; 1973. p. 395, 429–31.

[3] Van Holsbeeck MT, Introcaso JH. Sonography ofligaments. In: Musculoskeletal ultrasound. 2ndedition. St Louis (MO): Mosby; 2001. p. 171–92.

[4] Morrey BF, Tanaka S, An KN. Valgus stability ofthe elbow. A definition of primary and secondary


constraints. Clin Orthop Relat Res 1991;265:187–95.

[5] Miller TT, Adler RS, Freidman L. Sonography ofinjury of the ulnar collateral ligament of theelbow—initial experience. Skeletal Radiol 2004;33(7):386–91.

[6] Jacobson JA, Propeck T, Jamadar DA, et al. US ofthe anterior bundle of the ulnar collateralligament: findings in five cadaver elbows withMR arthrographic and anatomic comparison—initial observations. Radiology 2003;227(2):561–6.

[7] Timmerman LA, Schwartz ML, Andrews JR.Preoperative evaluation of the ulnar collateralligament by magnetic resonance imaging andcomputed tomography arthrography. Evaluationin 25 baseball players with surgical confirmation.Am J Sports Med 1994;22(1):26–31.

[8] Sasaki J, Takahara M, Ogino T, et al. Ultrasono-graphic assessment of the ulnar collateralligament and medial elbow laxity in collegebaseball players. J Bone Joint Surg Am 2002;84(4):525–31.

[9] Nazarian LN, McShane JM, Ciccotti MG, et al.Dynamic US of the anterior band of the ulnarcollateral ligament of the elbow in asymptomaticmajor league baseball pitchers. Radiology 2003;227(1):149–54.

[10] Hergan K, Mittler C. Sonography of the injuredulnar collateral ligament of the thumb. J BoneJ Surg Br 1995;77(1):77–83.

[11] Campbell CS. Gamekeeper’s thumb. J Bone JointSurg Br 1955;37(1):148–9.

[12] Noszian IM, Dinkhauser LM, Orthner E, et al.Ulnar collateral ligament: differentiation ofdisplaced and non-displaced tears with US.Radiology 1995;194(1):61–3.

[13] Stener B. Displacement of the ruptured ulnarcollateral ligament of the metacarpophalangealjoint of the thumb. A clinical and anatomicalstudy. J Bone J Surg Br 1962;44:869–79.

[14] Hoglund M, Tordai P, Muren C. Diagnosis byultrasound of dislocated ulnar collateralligament of the thumb. Acta Radiol 1995;36(6):620–5.

[15] Jones MH, England SJ, Muwanga CL, et al. Theuse of ultrasound in the diagnosis of injuriesof the ulnar collateral ligament of the thumb.J Hand Surg [Br] 2000;25(1):29–32.

[16] Bianchi S, Martinoli C. Hand. In: Ultrasound ofthe musculoskeletal system. Berlin: Springer;2007. p. 537–41.

[17] Boutry N, Lapegue F, Masi L, et al. Ultrasono-graphic evaluation of normal extrinsic andintrinsic carpal ligaments: preliminary experi-ence. Skeletal Radiol 2005;34(9):513–21.

[18] Finlay K, Lee R, Friedman L. Ultrasound ofintrinsic wrist ligament and triangular fibrocarti-lage injuries. Skeletal Radiol 2004;33(2):85–90.

[19] Jacobson JA, Oh E, Propeck T, et al. Sonographyof the scapholunate ligament in four cadaveric

wrists; correlation with MR arthrography andanatomy. AJR Am J Roentgenol 2002;179(2):523–7.

[20] Milz P, Milz S, Steinborn M, et al. Lateral ankleligaments and tibiofibular syndesmosis. 13-MHz high frequency sonography and MRIcompared in 20 patients. Acta Orthop Scand1998;69(1):51–5.

[21] Milz P, Milz S, Putz R, et al. 13 MHz highfrequency sonography of the lateral ankle jointligaments and the tibiofibular syndesmosis inanatomic specimens. J Ultrasound Med 1996;15(4):277–84.

[22] Peetrons PA, Silvestre A, Cohen M, et al. Ultraso-nography of ankle ligaments. Can Assoc Radiol J2002;53(1):6–13.

[23] Rogers LF. The ankle. In: Radiology of skeletaltrauma. 2nd edition. New York: ChurchillLivingston; 1992. p. 1351–3.

[24] Mengiardi B, Pfirmann CW, Vienne P, et al. Me-dial collateral ligament complex of the ankle:MR appearance in asymptomatic subjects. Radi-ology 2007;242(3):817–24.

[25] Lin CF, Gross ML, Weinhold P. Ankle syndes-motic injuries: anatomy, biomechanics, mecha-nism, of injury, and clinical guidelines fordiagnosis and intervention. J Orthop SportsPhys Ther 2006;36(6):372–84.

[26] Abernethy LJ, Lee YC, Cole WG. Ultrasoundlocalization of subperiosteal abscesses inchildren with late-onset osteomyelitis. J PediatrOrthop 1993;13(6):776–8.

[27] Abiri MM, Kirpekar M, Ablow RC. Osteomyelitis:detection with US. Radiology 1989;172(2):509–11.

[28] Cleveland TJ, Peck RJ. Case report: chronicosteomyelitis demonstrated by high resolutionultrasonography. Clin Radiol 1994;49(6):429–31.

[29] Howard CB, Einhorn M, Dagan R, et al. Ultra-sound in diagnosis and management of acutehaematogenous osteomyelitis in children.J Bone Joint Surg Br 1993;75(1):79–82.

[30] Nath AK, Sethu AU. Use of ultrasound in osteo-myelitis. Br J Radiol 1992;65(776):649–52.

[31] Quillin SP, McAlister WH. Rapidly progressivepyomyositis. Diagnosis by repeat sonography:a case report. J Ultrasound Med 1991;10(3):181–4.

[32] Steiner GM, Sprigg A. The value of ultrasound inthe assessment of bone. Br J Radiol 1992;65(775):589–93.

[33] Taneja K, Mittal SK, Marya SK, et al. Acute osteo-myelitis: early diagnosis by ultrasonography.Australas Radiol 1992;36(1):77–9.

[34] Wright NB, Abbott GT, Carty HM. Ultrasound inchildren with osteomyelitis. Clin Radiol 1995;50(9):623–7.

[35] Craig JG. Infection: ultrasound-guided proce-dures. Radiol Clin North Am 1999;37(4):669–78.



639

Musculoskeletal InfectionMahmud Mossa-Basha, MD, Marnix van Holsbeeck, MD*

- Disadvantages of ultrasound in theassessment of infection

- Infection in the adult populationSeptic arthritisPeri-prosthetic joint and bone infectionsCellulitisSeptic bursitisInfectious tenosynovitis (acute

suppurative tenosynovitis)AbscessOsteomyelitis

- Infection in the pediatric population

Advantages of ultrasound in the pediatricpopulation

CellulitisNecrotizing fasciitisOsteomyelitisPyomyositisSeptic arthritisInflammatory lymphadenitis

- Infection caused by foreign body- Interventional ultrasound- Summary- Acknowledgments- References

For multiple reasons, ultrasound (US) has be- repeated easily if necessary and can be done at the
come a useful tool in the diagnosis of infections.US is very sensitive in the detection of joint and ex-tracapsular fluid collections. On average, largejoints contain 0.1 cc of viscous fluid [1]. By avoidingthe aspiration of a normal joint, US sidesteps drytaps. US can detect joint effusions containing 1 ccor more fluid accurately. For the diagnosis of hip ef-fusion, numbers have been quoted as follows: forthe adult hip, 7 mm of anterior capsule distension,1 mm of asymmetric distension [2], or 3.2 mm ofpseudocapsule distension indicate effusion [3].These measurements, however, were considerednot useful by Weybright and colleagues [4]. Theyconcluded that reasons for inaccuracy may relateto hypoechoic synovium filling the anterior hipjoint recess and large patient body habitus. Suchconditions may mimic echoes caused by fluidwithin the synovium [4].
The role of US also is enhanced by its cost-effec-tiveness and its ready availability when comparedwith MR imaging and CT. US examinations are

Department of Radiology, Henry Ford Hospital, 2799 W* Corresponding author.E-mail address: [email protected] (M. van Holsbeeck)


bedside. If an abnormality is suspected, it can becompared with the contralateral side to assess forvariants [5]. Changes in effusion volume and syno-vial proliferation, indicating chronic infection, canbe monitored with follow-up scans.

US allows for visualization of fluid collectionsand can guide joint fluid aspiration, unlike fluoro-scopically guided joint aspirations (Fig. 1). It alsoallows for visualization of bony structures such asosteophytes and helps to stay clear from those pro-cesses that can hinder orthopedic taps. US allowsfor prompt real-time needle guidance into fluid col-lections or joint spaces. Confirmation of completefluid aspiration can be obtained during the proce-dure. Extra-articular fluid collections, such as bursaeand abscesses, which may be infected, can be seenand accessed separately [6]. One thus can avoidthese collections to prevent contamination of thejoint space [6]. Unlike studies by MR imaging andCT, ultrasound is not degraded by significant arti-facts caused by stainless steel or cobalt–chrome

est Grand Boulevard, Detroit, MI 48202, USA

.




Fig. 1. Reactive right hip effusion in a patient with right hip and groin pain, without fever or elevated whitecount. (A) Sonographic sagittal image of the right hip shows hypoechoic right hip effusion, with expansionof the joint capsule (arrow). (B) Comparison with the contralateral hip shows a normal-appearing left hip with-out effusion. (C) Needle was advanced into fluid collection (large arrow). Aspirate cultures were negative, andcell count was suggestive of inflammatory synovitis. Abbreviation: C, joint capsule.

Mossa-Basha & van Holsbeeck640

implants. This allows for evaluation of peri-pros-thetic infection. Because of the nonionizing qualityof US, the patient will not receive a radiation dose.Overall, US allows for better evaluation and safe as-piration of loculated fluid collections.

Disadvantages of ultrasound in theassessment of infection

There are numerous issues in the assessment ofmusculoskeletal infection by US. US imaging gener-ally is nonspecific in the assessment of infection. UScannot differentiate well between infectious and in-flammatory fluid collections (Fig. 2). Sonographicfindings, including power Doppler sonography,do not discriminate well between infectious/in-flammatory and noninflammatory musculoskeletal

processes [7]. For diagnostic evaluation, fluid aspi-ration or tissue biopsy for culture, Gram’s stain,and cell count must be obtained, in addition tothe diagnostic US examination [8]. In osteomyeli-tis, US only can assess cortical and subperiostealextension of disease; it is impossible, however, toevaluate spongious bone destruction or intrame-dullary extension [9]. Likewise, deep infectionswithin the pelvic or lumbar regions often are evalu-ated poorly [9].

Infection in the adult population

Septic arthritis

Acute septic arthritis is an infection that needs to bediagnosed and treated early and quickly because of

Fig. 2. (A) Extra-articular fluid collection in patient with history of intravenous drug abuse presenting with pro-gressive right hip pain. There is extra-articular right hip fluid collection that is complex appearing, possibly bur-sal in location (arrow). Right hip effusion is also present, with thickened capsule (arrowhead). (B) IncreasedDoppler flow is seen in the subsynovial layer. This initially was thought to represent acute septic arthritis,with adjacent infective bursitis, but the right hip effusion was found to be reactive in nature. The fluid collectionoverlying the right hip was drained, and cultures grew Staphylococcus aureus colonies. Abbreviations: C, jointcapsule; RF, right femoral head.

Musculoskeletal Infection 641

possible long-term sequelae that can result [1]. Bac-terial arthritis can result in irreversible loss of jointfunction in 25% to 50% of cases [10]. Patients com-monly present with fever, joint pain, erythema overthe joint, swelling, and limited range of motion[11]. These symptoms, however, may not be presentin elderly patients or in patients on corticosteroids[8]. Fifty percent of the time, patients have positiveblood cultures, with 75% to 90% having positiveGram’s stain of synovial fluid upon aspiration[8,12].

Infection generally occurs through hematoge-nous spread, because there is no basement mem-brane protecting the highly vascular synovium [8].Infection also can occur after penetrating jointtrauma, intra-articular corticosteroid injection,and with joint prostheses. The knee is the mostcommonly affected joint, involved in 40% to 50%of septic arthritides [8]. The hip is second, involvedin 25% of cases, followed by the shoulder, which isinvolved in 15% of cases [8].

The most common pathogen in acute septic ar-thritis is Staphylococcus aureus, which is involved in46% to 56% of cases [12–14]. Other organismsthat will infect the joint include Streptococcus speciesand Neisseria gonorrhea. N gonorrhea septic arthritisoccurs in 1% of adult gonococcal urethritis, but oc-curs in 75% of disseminated gonococcal cases[15,16]. Gonococcal septic arthritis commonly in-volves multiple joints [17]. Another characteristicfinding in disseminated gonococcal infection isacute asymmetric tenosynovitis, which occurs in68% of cases [18]. This generally involves the dor-sum of the hand and wrist and occasionally the

ankle [18]. Gonococcal infection should be consid-ered in adolescents or adults who present withacute asymmetric tenosynovitis and arthritis inmore than one joint. Acute septic arthritis occasion-ally can be viral or parasitic.

Risk factors for joint infection include immuno-compromised state, joint prosthesis, diabetes melli-tus, dialysis, intravenous drug abuse, age greaterthan 60 years, corticosteroid joint therapy, rheuma-toid arthritis, sickle cell disease, and prior jointdamage [8,19]. The most significant risk factorsare overlying skin infection and the presence ofa joint prosthesis [20]. Generally, septic arthritis ismore common in children.

Septic arthritis can be a complication of rheuma-toid arthritis. Rheumatoid arthritis causes jointdamage, allowing for easier joint seeding by hema-togenous spread. Generally, the patients also areimmunosuppressed, allowing for prolonged hema-togenous exposure and decreased resistance to in-fection. Patients who have rheumatoid arthritishave a tenfold higher incidence of septic arthritisthan the general population [20]. The most com-monly involved joint is the shoulder, seen in greaterthan 70% of the cases [8]. Twenty percent of thetime, more than one joint is involved. Physical ex-amination generally is noncontributory, becauseacute joint swelling can be seen both in infectionand rheumatoid exacerbation.

The differentiation between superimposed infec-tion over rheumatoid arthritis and rheumatoid ex-acerbation also can be difficult sonographically.Both can have acutely increased joint effusion andvariable synovial thickening. Generally, however,


one can expect to see joint effusion with internalechoes without increased synovial thickening injoint infection [8]. With rheumatoid arthritis exac-erbation, generally, joint space effusion will be par-alleled with synovial thickening [8]. Hypoechoicfluid collections without color Doppler also canhelp in differentiating infection and rheumatoid ex-acerbation [21]. US is most helpful in evaluatingchanges in the amount of effusion and synovialproliferation. These changes can be assessed withfollow-up and with US-guided arthrocentesis [8].

Although US is generally good at detecting fluidcollections, sonographic findings are not specificfor infection. Half of the patients with joint space ef-fusions and symptoms of irritable hip had septic ar-thritis [22]. In addition, a normal sonographicappearance of the joint space cannot exclude infec-tion. This statement was made more specificallyin assessing children according to Gordon andcolleagues [23]. Zawin and colleagues [22], however,states that normal appearance excludes infection, intheir experience. US is not specific in differentiatingbetween infectious and inflammatory processes ornoninflammatory processes. For definitive diagno-sis, joint aspiration and fluid analysis are necessary,for which US is very helpful in providing guidance.

With acute septic arthritis, generally there will bean acute joint effusion without significant synovialthickening [8]. The joint fluid can have numerousappearances. Most commonly, the fluid can be hy-poechoic with hyperechoic debris or gas bubbles.There are often anechoic regions in the fluid. Gasbubbles normally will show dirty shadowing. Lesscommonly, the fluid collection can be entirely an-echoic. Rarely, the fluid collection can appear ho-mogenously hyperechoic. This finding is seenmore commonly with superficial joint infections,such as tibio–talar joints or sterno-clavicular joints.With real-time US, with compression, fluctuationsand swirling can be seen within the fluid collection,secondary to debris [8]. Although significant syno-vial thickening generally is not seen, synovial irreg-ularity and mild joint capsule thickening can bepresent. The synovium and joint capsule also canappear hyperechoic. This cannot always be seen,however, especially in larger patients.

The classic finding in septic arthritis with colorDoppler flow is hyperemia in the joint capsuleand subsynovial layers surrounding the infected ef-fusion. These findings are not always seen with in-fected joints, and power Doppler cannot excludeseptic arthritis [7]. Hyperemia of the joint capsulealso can be seen in noninfectious inflammatoryprocesses. Generally, noninflammatory effusionswill not have surrounding hyperemia [21].

Chronic septic arthritis generally has a moreinsidious onset than acute infection. Causes of

chronic septic arthritis include mycobacterial(TB or atypical), fungal, borrelial (Lyme disease),syphilitic, and brucellosis seeding. These diseasespresent with synovial proliferation. The synovialmembrane may appear hyperechoic. Color Dopplerflow often shows hyperemia in the capsule, synovi-um, and subsynovial layers. When non-US- guidedarthrocentesis is attempted, dry taps commonly oc-cur in chronic synovial disease. In these diseases, UScan guide both aspiration and synovial biopsy.

Peri-prosthetic joint and bone infections

Joint prostheses are risk factors for joint infection.Infection can occur after any time interval after im-plant placement. The risk of infection increaseswith the number of prior surgeries. Generally, theincidence of infection with total knee arthroplastyis 0.5% to 2%, but can be as high as 10% (or higherwith high virulence organisms) with revision ar-throplasty, in those with chronic medical condi-tions, or in those who are on steroids [24,25].Peri-prosthetic infection must be strongly suspectedin patients who have prosthesis and new joint painor in those who have an arthroplasty and fever ofunknown origin. It is especially important to bevigilant because of long-term sequelae that can re-sult if left untreated. All peri-prosthetic fluid collec-tions outside the immediate postoperative period(2 weeks) are suspicious for infection.

The most common organisms encountered inprosthetic infections include: Staphylococcus epider-midis (30% to 43%), Staphylococcus aureus (12% to23%), mixed flora (10%–11%), Streptococcus species(9% to 10%), gram-negative bacilli (3% to 6%), en-terococci (3% to 7%), and anaerobes (2% to 11%)[26–28]. There are no microbes detected in 11% ofclinically apparent infections [29]. Common con-taminants include normal skin flora, includingcoagulase-negative Staphylococcus and Propionibacte-rium acnes. The presence of the latter-mentionedmicroorganisms can be determined to representreal infection if similar growth can be shown inmultiple specimens obtained from the joint at dif-ferent time intervals. Propionibacterium acnes maybe a common shoulder prosthesis infection, repre-senting 16% of shoulder prosthetic infections,while only representing less than 2% of other jointinfections [28,30]. Antibiotic prophylaxis has de-creased intraoperative infection to less than 1% inshoulders and hips and 2% in knees [30–32].

Peri-prosthetic infections generally are catego-rized based on when the infection takes place. Earlyperi-prosthetic joint infection occurs less than3 months after surgery, and represents 29% of cases[33,34]. Early infections usually are acquired intra-operatively, either from implant seeding, woundinfection, or from the skin [29]. These infections


generally present as acute joint pain, effusion, ery-thema, warmth at the joint, and fever. These infec-tions usually are caused by virulent organismssuch as Staphylococcus aureus and gram-negativebacilli (including Pseudomonas aeruginosa) [29]. Pa-tients may develop cellulitis and peri-prosthetic si-nus tracts. Delayed infections have a more subtlepresentation and usually occur 3 to 24 months aftersurgery [34]. These infections also are acquired in-traoperatively, but there is a longer lag period forthe organisms to proliferate and cause symptoms.Delayed infections are caused by less virulent or-ganisms such as Staphylococcus epidermidis andPropionibacterium acnes [29]. Patients generally pres-ent with persistent joint pain, and implant loosen-ing is generally seen on radiographic studies. It isdifficult to differentiate delayed infection fromhardware failure. Delayed infections represent 41%of all cases [33]. The third form of prosthetic infec-tion is called late infection [33]. Late infections pres-ent after greater than 24 months postoperatively,and are a result of hematogenous seeding from bac-teremia [34]. These represent 30% of all cases [33].From prior studies, it was thought that most infec-tions were obtained through draining wounds[35], but through more recent studies, it has beenfound that most infections occur through hematog-enous seeding [36,37]. The decrease in infections bydirect wound contamination is thought to be causedby increased use of prophylactic antibiotics andimproved operating room environments [37].

US is a very useful tool in evaluating peri-prostheticjoint infections. US imaging of the tissues aroundprostheses is not degraded by metallic implants. USallows for evaluation of articular and peri-articulartissues. This investigational method is sensitive indetecting joint effusions, and subsequently guidingneedle aspiration (Fig. 3).

With peri-prosthetic septic arthritis, joint effusionshould be present. If there is a normal capsule (bonedistance less than 3.2 mm at the affected joint),there is no need for joint aspiration for the evalua-tion of infection [3]. Anterior pseudocapsule disten-sion of greater than 3.2 mm with hip jointprostheses indicates possible infection, althoughthis was disputed to be inaccurate by Weybrightand colleagues [4]. The most reliable criterion forperi-prosthetic infection is large joint effusion(mean bone to capsule distance of 10.2 mm) withcontiguous extra-articular fluid collection [3]. Dif-ferentiation between effusion caused by infectionversus implant failure is difficult. Generally, effu-sion caused by infection will appear more echogenicthan simple fluid and contain hyperechoic debris,but this is not always seen.

Joint aspiration is needed for definitive diagnosis.Diagnosis is based on fluid aspirate neutrophil and

leukocyte count, and Gram’s stain and culture. Sy-novial fluid neutrophil count greater than 65%has a specificity of 98% and sensitivity of 97% indetection of infection, if there is no underlying in-flammatory disease [38]. Aspirate leukocyte countgreater than 1700/mm3 has a sensitivity of 94%and specificity of 88% [38].

Cellulitis

Cellulitis is generally a diagnosis based on clinicalfindings. There is limited utility for sonography.Patients generally present with swollen, erythema-tous, painful extremities or body region [9]. The pa-tient may have an associated fever. Staphylococcusaureus and Streptococcus species are the most com-mon pathogens.

US generally does not contribute to the initial di-agnosis of cellulitis, but may be helpful in follow-up. When patients do not improve with treatment,US can be used to find and aspirate fluid collectionsfor fluid analysis. Abscesses within the soft tissuesalso can be found by US. Sonographic findingswith cellulitis include diffuse hyperechoic skinand subcutaneous tissue thickening (Fig. 4) withcobblestone appearance and anechoic strandswithin hyperechoic soft tissues (Fig. 5) [39]. Thesefindings are nonspecific, and are seen with any softtissue edema. Hyperemia may be seen within thesoft tissues with color Doppler flow.

Septic bursitis

Septic bursitis symptoms frequently can be con-fused with septic arthritis, with joint pain andasymmetric joint swelling. The most common or-ganism involved is Staphylococcus aureus. The olecra-non and prepatellar bursae are involved mostcommonly [40]. Sonographic findings are not spe-cific in determining infectious versus traumatic eti-ologies of bursal inflammation [9]. Aspiration isrequired for definitive diagnosis.

Septic bursitis can have many different presenta-tions, similar to septic arthritis. Fluid can be hypo-echoic with hyperechoic internal debris, or appearanechoic (Fig. 6). The bursa can have thickenedhyperechoic walls. Color Doppler flow may showhyperemia in the walls of the fluid collection, butthis also does not have to be present.

Infectious tenosynovitis (acute suppurativetenosynovitis)

Infectious tenosynovitis usually results from pene-trating trauma, such as after bite or puncturewound. With trauma, the digital flexor tendonsusually are involved. The most common organismsinvolved are Staphylococcus aureus and Streptococcuspyogenes [40]. Septic tenosynovitis also can be a re-sult of disseminated gonococcal infection, in which

Fig. 3. Chronic peri-prosthetic joint infection in a patient with bilateral hip prostheses, fever, and bilateral hippain. (A) Anteroposterior view of right hip shows loosening of acetabular prosthesis with peri-prosthetic lu-cency, thought initially to represent particle disease. (B) Sonographic sagittal image of the right hip showsperi-prosthetic right hip joint effusion, which contains internal debris (arrow). (C) Panoramic sonographic sag-ittal image of the right hip shows right hip peri-prosthetic fluid collection, which contains internal debris (ar-row), extending from the right hip, with fluid along the prosthesis neck. Note ring-down metallic artifactdeep to acetabular cup and metallic femoral neck prosthesis (*). Joint fluid was aspirated, and cultures grewout Mycobacterium tuberculosis (P: femoral prosthesis, F: femoral shaft).


tenosynovitis will occur 68% of the time [18]. Withgonococcal tenosynovitis, the dorsum of the wristsand hands and occasionally the ankles are involvedin an asymmetric distribution [18]. Prompt treat-ment is paramount, to avoid tendon necrosis andinvolvement of other palmar spaces [41]. Infectioustenosynovitis can present symptomatically in a sim-ilar manner to septic arthritis, with local swelling,erythema, and pain.

Sonographically, it is difficult to differentiateinfectious from noninfectious etiologies of teno-synovitis. US can be helpful in differentiating teno-synovitis from other causes of local inflammationand pain such as septic arthritis or cellulitis.

With acute infectious tenosynovitis, fluid shouldbe present within the tendon sheath. This fluid canhave many different presentations, either being

hypoechoic, anechoic, or hyperechoic, much likethe fluid seen with septic arthritis (Fig. 7). The af-fected tendon will be enlarged when comparedwith the contralateral side [41]. Color Dopplerflow may show hyperemia surrounding the fluidcollection, within the tendon sheath (Fig. 7C, D).Foreign bodies also may be seen, which commonlyoccur secondary to penetrating trauma. Such for-eign bodies must be removed to treat the tenosyno-vitis more definitively.

Subacute infectious tenosynovitis commonly iscaused by Mycobacterium species and fungal infec-tions. Such infections commonly are acquired afterhematogenous spread, as opposed to infection sec-ondary to penetrating trauma. Sonographically, thismay present with hypoechoic or isoechoic, non-compressible synovial proliferation surrounding

Fig. 4. Cellulitis. Ultrasound of the thigh shows in-creased echogenicity (arrow) and sound beamattenuation representing cellulitis. (Courtesy of J.Jacobson, MD, Ann Arbor, MI.)


the tendon. There is a paucity of fluid surroundingthe tendon sheath. The tendon will be enlargedwhen compared with the contralateral side [41].Diffuse hyperemia also can be seen within thetendon sheath.

Abscess

US is the modality of choice in assessing superficialabscesses, but US generally is not useful in assessingdeeper abscesses. For deep-seated abscesses, such aspelvic and lumbar region abscesses, US frequentlygives false-negative results.

Sonographically, abscess can have many differentpresentations. Infected fluid collections can appear

Fig. 5. Cellulitis in patient with history of intravenousdrug abuse. There is cobblestone appearance of thesoft tissues, with hypoechoic strands (arrow) ofedema interspersed within hyperechoic soft tissues(arrowhead). These findings are nonspecific and canbe seen with soft tissue edema of any etiology.

anechoic, hypoechoic, or hyperechoic, or be ofmixed echogenicity. Hyperechoic internal echoescan be seen, which are secondary to gas bubblesor aggregates of fibrin and white blood cells. Septa-tions also can be seen. With abscess, the marginscan be well-circumscribed or hazy. There also maybe a thickened, hyperechoic rim. Compression dur-ing real-time imaging will reveal swirling within thefluid collection with isoechoic or hyperechoic fluidcollections. Color Doppler flow will show increasedflow at the periphery of the abscess, with absentflow within the fluid collection.

Differentiation between soft tissue hematomaand abscess can be very difficult sonographically.Hematomas can appear isoechoic, hyperechoic, oranechoic. Hyperechoic debris within hematomascan be secondary to small clots. On serial follow-up, long-standing hematomas will become progres-sively anechoic. Definitive diagnosis is based onhistory and fluid aspiration.

Osteomyelitis

Acute hematogenous osteomyelitis most commonlyoccurs in young children and the elderly [9]. Themost common organisms involved are Staphylococ-cus aureus, followed by Streptococcus species, Salmo-nella typhi and gram-negative rods in adults.

US has somewhat limited use in the diagnosis ofosteomyelitis, because US cannot image beyond thecortex of osseous structures [42]. MR imaging is thestudy of choice for the diagnosis of osteomyelitis.The earliest sign seen on US is soft tissue swellingadjacent to the bone. Sonographically, visualizationof subperiosteal fluid or a fluid collection adjacentto the bone is highly suggestive of early osteomyeli-tis, especially in children [43,44]. US also can aid inguiding subperiosteal fluid aspiration for microbio-logical analysis [43,44]. Unlike MR imaging or CT,US is not degraded by metallic densities, and thus itis helpful in assessing osteomyelitis complication offixation hardware. Metallic hardware loosening andfluid collections or surrounding sinus tracts can beseen.

Infection in the pediatric population

Advantages of ultrasound in the pediatricpopulation

US can be more beneficial for the diagnosis of mus-culoskeletal infection in the pediatric populationthan in the adult population for multiple reasons.In children, there is a higher ratio of cartilage tobone than in adults. Children have a higher ratioof lean mass to fat, allowing for improved scanquality. As with adults, the contralateral side canbe scanned for comparison, and US can guide aspi-ration of fluid collections.

Fig. 6. Iliopsoas septic bursitis versus abscess in a patient with history of Crohn’s disease. (A) Sonographic sagittalimages of the right hip show mixed echogenicity, complex fluid collection adjacent to the right femoral headand neck, with multiple echogenic foci with dirty shadowing, likely representing gas (arrow). (B) Fluid collectionagain seen in a different plane. (C) Needle advanced into fluid collection (arrowhead). Aspirate cultures grewout multiple organisms, including Klebsiella pneumoniae, Candida albicans and Enterococcus faecium. Abbrevi-ation: F, femoral head.


Cellulitis

Similar to adults, the diagnosis of cellulitis withchildren is based on clinical diagnosis, with symp-toms of lower extremity swelling, pain, erythema,and fever. Cellulitis has a predilection for involve-ment of the lower extremities in children. Themost common pathogens are Staphylococcus aureusand Streptococcus pyogenes [1].

Sonographic findings of cellulitis in children arevery similar to those seen in adults. Soft tissueedema with hypoechoic strands within hyperechoicsoft tissue, or diffuse increased echogenicity is seen.US is most helpful in guidance of aspiration of fluidcollections, and if the patient does not respond totreatment, follow-up US is useful in showingabscess formation [39]. Early osteomyelitis fre-quently can mimic cellulitis. With follow-up scans,

subperiosteal fluid collection can be seen in osteo-myelitis. Patients who underwent sonographicallyguided fluid aspiration of fluid collections with per-sistent cellulitis were shown to have shortened hos-pital stays and decreased duration of fever [45].

Necrotizing fasciitis

Necrotizing fasciitis is a rapidly progressive infec-tion that spreads along fascial planes and can leadto severe debilitation and possibly amputation ifnot treated promptly [1,46]. For this reason, rapiddiagnosis and treatment are paramount. The mostcommon pathogens are Staphylococcus aureus andStreptococcus pyogenes [1].

Early necrotizing fasciitis can resemble the softtissue changes of cellulitis with soft tissue swelling,soft tissue edema, and hypoechoic regions within

Fig. 7. Infectious tenosynovitis in a patient with history of cellulitis and intravenous drug abuse. (A) Sagittal viewof the left wrist shows complex fluid with internal debris within tendon sheath coursing along dorsal aspect ofleft second metacarpal base (arrow), likely representing extensor carpi radialis longus tendon. (B) Transverseview of the left wrist redemonstrates complex fluid collection within tendon sheath (arrow). (C, D) Color Dopp-ler images show hyperemia of surrounding tendon sheath and soft tissues. (E) Needle tip in radial side of tendonsheath fluid collection (arrowhead). Fluid, which was purulent in appearance, was aspirated and cultures grewnon-Streptococcus pneumoniae alpha-hemolytic Streptococcus. Abbreviations: T, extensor carpi radialis longustendon; TS, tendon sheath.


hyperechoic soft tissue. Subsequently, fascial thick-ening and accumulation of cloudy or loculatedfluid within the fascia or in the tissues deep to thefascia should alert one to the diagnosis. There canbe gas in the soft tissues also [1,46].

Osteomyelitis

There is increased use of US for the diagnosisof osteomyelitis, especially in children, although

a negative US does not preclude the diagnosis[47]. Manifestations of osteomyelitis depend onthe age group. In infants, it is more common tohave joint and epiphyseal infections than osteomy-elitis in the diaphysis. This is because the diaphysealblood vessels traverse the growth plate to reach theepiphysis [48]. In older children, metaphyseal in-fections are more common. This is because thegrowth plate serves as a barrier for diaphyseal blood


vessels. These vessels terminate in sinusoidal ve-nous structures within the metaphysis, where infec-tions commonly start. Periosteal elevation is morecommon in children than adults, because the peri-osteal layer is attached more loosely in children [8].With pediatric osteomyelitis, infected fluid willtrack through the Haversian and Volkmann canalsinto the subperiosteal space because of increasedpressure within the medullary cavity [1]. The mostcommon organisms involved in pediatric osteomy-elitis are Staphylococcus aureus, Streptococcus species,Escherichia coli, Pseudomonas Aeruginosa, and lesscommonly Haemophilus influenzae [1,46].

US findings of osteomyelitis generally precede ra-diographic findings by several days [44,49]. Withearly osteomyelitis, periosteal thickening of greaterthan 3 mm is seen in 33% to 35% of cases [44].In 93% of cases, soft tissue edema and deep soft tis-sue swelling adjacent to the bone can be seenwithin 24 hours of symptom development [43].This is a fairly specific finding. Periosteal elevationof greater than 2 mm is indicative of subperiostealabscess formation [43]. This is represented by a hy-poechoic or hyperechoic spindle-shaped fluid col-lection along the bony cortex (Fig. 8). This fluidcollection can be elongated or focal and crescentic.Searching for this fluid collection is necessary,because drainage under US guidance should beconsidered. As osteomyelitis progresses, corticalerosions can develop. These can be seen sonograph-ically by increased transmission through bone andirregularity of the bony surface. Intra-articular fluid

Fig. 8. Osteomyelitis and subperiosteal abscess. Ultra-sound image of dorsal third metacarpal (MC) showsheterogeneous, spindle-shaped, subperiosteal fluidcollection representing abscess (arrow). Note is alsomade of joint effusion (arrowhead). (Courtesy ofJ. Jacobson, MD, Ann Arbor, MI.)

collections can develop with epiphyseal infections.Color Doppler flow generally will show hyperemiaaround fluid collections as soon as 4 days after theonset of symptoms [50].

Pyomyositis

Pyomyositis is a rare infection of muscle. Generally,striated muscle is highly resistant to bacterial infec-tion. This type of infection most commonly occursin tropical regions [1]. Predisposing factors in thesetting of a moderate climate include trauma, dia-betes mellitus, chronic steroid use, connective tissuedisease, HIV, and other forms of immunosuppres-sion and malnutrition [51,52]. Children are af-fected in one third of cases. The most commonorganism involved is Staphylococcus aureus in thetropics [53].

There are two stages of pyomyositis. Sonographi-cally, stage 1 shows localized muscle edema withdistortion of muscle fiber planes by ill-defined re-gions of hypoechoic fluid. This stage can be treatedwith antibiotics. Stage 2 involves intramuscular ab-scess formation. The fluid collection may appearhypo, hyper, or isoechoic to soft tissues (Fig. 9)[1,54]. Internal echoes may be seen within the fluidcollection. As with soft tissue abscesses, swirling offluid and echoes will be seen with compression. Ifthere is gas seen within edematous, inflamed mus-cle, this is suggestive of abscess formation by anaer-obic bacteria.

Septic arthritis

According to Jackson and Nelson [55], the kneejoint is the most commonly infected joint in chil-dren, affected in 41% of cases, followed by the hipin 23% of cases. Hip infection is the most worri-some of pediatric joint infections because of therisk of femoral head necrosis, dislocation, andgrowth arrest. If diagnosed late, this infection canlead to permanent disability. US, rectal tempera-ture, erythrocyte sedimentation rate (ESR), andC-reactive protein have been shown to be themost reliable group of parameters to acutely differ-entiate between pediatric hip infection and othercauses of irritable hip [56]. Septic arthritis is morecommon in neonates than in older children. Septicarthritis results most commonly from hematoge-nous seeding, but it also can result from extensionof osteomyelitis into the joint. In neonates, septicarthritis is associated more commonly with meta-physeal osteomyelitis. Approximately 60% to100% of neonates who have septic arthritis have ad-jacent osteomyelitis [57]. This occurs because oftransphyseal vessels that transgress by 6 monthsof age. Also in neonates, there are synovialreflections over the metaphyses, which allow for

Fig. 9. Pyomyositis in a patient with history of intravenous drug abuse presenting with left anterior thigh pain,swelling, and fever. (A) Sagittal and (B) transverse images show intramuscular heterogeneous fluid collection,which crosses the anterior fascial boundary investing the rectus femoris. Extension into the subcutis noted(arrow), which represents pyomyositis stage 2. Aspirate cultures grew out methicillin-resistant Staphylococcusaureus. Abbreviations: S, subcutaneous tissue; F, fascia; R, rectus femoris; VI, vastus intermedius.


extension from the joint into the metaphyseal bone[58,59].

The most frequent organisms found in pediatricseptic arthritis are Staphylococcus aureus, followedby Streptococcus pneumoniae and Streptococcus pyo-genes. After 2 years of age, Staphylococcus comprises50% of all cases [57]. In sickle cell anemia, Salmo-nella is implicated in 83% of all bone and jointinfections [60]. Microbes commonly involved inneonatal bone and joint infections are Group BStreptococcus and Escherichia coli. In contrast, Neisse-ria gonorrhea is the most common cause of arthritisin adolescents. In the adolescent population asa whole, N gonorrhea is the most common causeof polyarticular septic arthritis. With infants lessthan 3 months of age, Staphylococcus aureus(62%), Candida albicans (17%), and gram-negativebacilli (15%) were seen most commonly in nosoco-mial infections. With this same age group, commu-nity-acquired infections most commonly werecaused by streptococcus species (52%), staphylo-cocci (26%), and gonococci (17%) [61].

Clinical evaluation generally can help in makinga correct diagnosis. The patients will present withfever, nonweight bearing on the affected joint, ery-thema, and a tense joint effusion with restrictedmotion. Laboratory studies will show erythrocytesedimentation rate (ESR) greater than 40 with pe-ripheral white count of greater than 12,000. If theseclinical findings are present, the likelihood of septicarthritis being the diagnosis is greater than 99%[62]. Eich and colleagues [56] showed a rectaltemperature greater than 38.0�C, ESR greater than20 mm/h and C-reactive protein greater than 20mg/L had a sensitivity of 100% and specificity of

89%. The differential diagnosis for the clinical pre-sentation of septic arthritis includes juvenile rheu-matoid arthritis, trauma, osteomyelitis adjacent tothe joint, cellulitis, Henoch-Schoenlein purpura,sickle cell crisis, hemophilia, and in adolescentsand adults, Reiter’s, gout. Calcium pyrophosphatedeposition disease also should be included.

In the pediatric population as in adults, US is verysensitive in detecting joint space effusions but notspecific in differentiating between inflammatory,noninflammatory, and septic pediatric joint pro-cesses. In the pediatric population, absence of jointeffusion essentially excludes the diagnosis of septicarthritis. The findings in pediatric septic arthritis arevery similar to those seen in adults, with fluid col-lections that can appear anechoic, hyperechoic orhypoechoic, with internal echoes representing gasor debris. In children who have hip joint effusion,increased flow surrounding the joint on colorDoppler had a sensitivity of 27% and a specificityof 100% for the diagnosis of septic arthritis [7]. Aswith all infections, definitive diagnosis only couldbe attained with joint aspiration and fluid analysis.

Inflammatory lymphadenitis

Reactive lymph nodes are seen commonly in chil-dren. These are palpable, nontender, enlargedlymph nodes. The peak incidence of inflammatorylymphadenitis is in early school-aged children.Generally, the children will have no clinical symp-toms, with no fever or tenderness.

These lymph nodes maintain normal anatomicarchitecture, with central echogenicity on US fromreflective interfaces between medullary fat and lym-phatic sinuses [63]. These nodes are elliptic in

Fig. 10. Cat scratch disease. Ultrasound of axilla showsenlarged, hypoechoic axillary lymph node (arrow)with preserved echogenic hilum (arrowhead). (Cour-tesy of J. Jacobson, MD, Ann Arbor, MI.)


shape, with L/S ratio greater than 2 [64]. There is nosurrounding soft tissue inflammation. On colorDoppler, there is a hilar type vascular pattern in48% of cases, and central radial pattern in 20%.The resistive index of the lymphatic vessels shouldbe less than 0.8 [65–67].

With acute inflammatory lymph nodes, patientswill have symptoms that differ significantly from re-active lymph nodes. Patients will have fever andlymph node tenderness.

Sonographically, the central echogenicity may beabsent, narrow, and irregular [64]. The lymph nodecan appear heterogeneous, with hypoechoic regionssecondary to necrosis and suppuration [64]. Theremay be hyperechogenicity of the surrounding softtissues caused by surrounding inflammation. Hypo-echogenicity of the lymph node parenchyma witha hyperechoic hilum also may be seen, most com-monly in cubital and inguinal lymph nodes [64].

Color Doppler flow patterns with abnormallymph nodes have a different appearance than nor-mal lymph nodes. Generally, a peripheral vascularpattern can be seen, with resistive indices greaterthan 0.8 [65–67]. Infectious mononucleosisshowed a central radial pattern in 75% of cases.Bacterial inflammatory lymph nodes can have a var-iable appearance [64].

The most common cause of head and neck gran-ulomatous inflammatory lymphadenopathy in theUnited States is nontuberculous Mycobacterium in-fection. This includes Mycobacterium avium intracel-lulare, Mycobacterium scrogulaceum, Mycobacteriumbovis, and Mycobacterium kansasii [68]. Other etiolo-gies include Mycobacterium tuberculosis, syphilis,leprosy, Bartonella henslae, tularemia and histoplas-mosis. Children between 2-5 years old are com-monly affected [68]. This is a very common causeof surgical excision of lymph nodes.

Most of the reports of sonographic findings ofgranulomatous inflammatory lymphadenopathyare in relation to tuberculosis (TB), but studies re-port that these findings can be extrapolated tonon-TB mycobacterial cases. Generally, the lymphnode parenchyma appears heterogeneous second-ary to hypoechoic necrotic foci, and echogenic re-gions secondary to calcifications or hyalinosis. Thelymph node borders may be hazy because of sur-rounding soft tissue edema. There may be coales-cence of lymph node groups, leading to theappearance of masses [69,70]. On color Dopplerflow, there can be hilar or mixed vascular patternin 72% of cases. The hilar vessels will be displacedin 78% of cases [71].

Cat scratch disease is caused by Bartonella henslae,another example of chronic granulomatous lymph-adenopathy. This infection develops after 1 to4 weeks adjacent to site of skin puncture from an

animal bite or scratch. The first symptom is painfullymphadenopathy, which commonly starts in theleft axilla. The infection subsequently spreadsthroughout the lymphatic system. Sonographically,enlarged hypoechoic lymph nodes with echogenichila are seen (Fig. 10). Heterogeneous hypoechoicregions can be seen because of necrosis. Suppura-tive lymphadenitis frequently will develop. Therecan be surrounding soft tissue edema and perinodalinflammation [72,73]. Usually, only a single lymphnode group will be involved. Color Doppler flowwill show hyperemia in all involved lymph nodes.

Infection caused by foreign body

Foreign bodies frequently lead to infections becauseof seeding of and through microbes trackingthrough the open wound into the soft tissues.Chronic recurrent infections also can occur becauseof bacterial seeding [74]. Ultrasound has 83% sen-sitivity and 59% specificity for foreign body locali-zation [75]. The sensitivity for wood localizationis 93%, while that for plastic is 73% [75].

The foreign body will have a sonographic appear-ance consistent with its makeup. Wooden foreignbodies will be hyper-reflective, with acoustic shad-owing. Metal and glass will show posterior reverber-ation artifact. With infection and inflammation,there will be a halo surrounding the foreign body,and possibly a fluid collection (Fig. 11).

Interventional ultrasound

US-guided arthrocentesis provides for conclusivediagnostic evidence for infection. Generally, the

Fig. 11. Wooden foreign body. Ultrasound of the finger longitudinal (A) and transverse (B) to a wooden foreignbody shows the hyperechoic linear foreign body (arrow) and adjacent hypoechoic fluid collection (arrowhead)representing abscess. (Courtesy of J. Jacobson, MD, Ann Arbor, MI.)


decision for US-guided arthrocentesis is based onclinical findings and clinical suspicion as opposedto radiographic findings. Aspirated fluid frequentlyis analyzed for Gram’s stain, culture, cell count, anddifferential.

US allows for optimal visualization of fluid col-lections. Loculations can be visualized in fluid col-lections, which will allow for improved aspiration.US prevents dry taps, which commonly occur withblind or fluoroscopically guided arthrocenteses.Fluoroscopic images may show bony structureswell, but do not allow for fluid visualization. Post-aspiration sonographic images can assess whetherthe effusion was drained completely.

US allows for guidance of placement of the aspi-ration needle into the joint space. The needle can bevisualized within the fluid collection. Extra-articularfluid collections, such as abscesses or bursae, whichmay be infected, can be visualized, and avoided,preventing joint space contamination. US helpsdetect accessible spaces between osteophytes injoints deformed by trauma or degenerative jointdisease.

Summary

US has proven to be a very useful tool in the diag-nosis of musculoskeletal infection. US is sensitivein the detection of joint effusion. Although US find-ings in inflammation are not specific, its main util-ity is in guidance of fluid aspiration, a procedurenecessary for definitive diagnosis of infection. Ad-vantages of the use of US also stem from its avail-ability, use at the bedside, affordability, and abilityto compare with the nonaffected side. US is a non-ionizing examination, and thus can be used readilyin children. Serial examinations can be conductedeasily, allowing for detecting changes in effusionsize and synovial proliferation.

Acknowledgments

Special thanks to David Brown for helping in creat-ing the figures. Thanks also goes out to NanditaMani for her help in formatting the paper.

References

[1] Robben SG. Ultrasonography of musculo-skeletal infections in children. Eur Radiol 2004;14(Suppl 4):65–77.

[2] Koski JM, Anttila PJ, Isomaki HA. Ultrasonogra-phy of the adult hip joint. Scand J Rheumatol1989;18(2):113–7.

[3] van Holsbeeck MT, Eyler WR, Sherman LS, et al.Detection of infection in loosened hip prosthe-ses: efficacy of sonography. AJR Am J Roentgenol1994;163(2):381–4.

[4] Weybright PN, Jacobson JA, Murry KH, et al.Limited effectiveness of sonography in revealinghip joint effusion: preliminary results in 21 adultpatients with native and postoperative hips. AJRAm J Roentgenol 2003;181(1):215–8.

[5] Adam R, Hendry GM, Moss J, et al. Arthrosonog-raphy of the irritable hip in childhood: a reviewof 1 year’s experience. Br J Radiol 1986;59(699):205–8.

[6] Lombardi T, Sherman L, van Holsbeeck MT. So-nographic detection of septic subdeltoid bursitis:a case report. J Ultrasound Med 1992;11(4):159–60.

[7] Strouse PJ, DiPietro MA, Adler RS. Pediatric hipeffusions: evaluation with power Doppler sonog-raphy. Radiology 1998;206(3):731–5.

[8] van Holsbeeck MT, Introcaso JH. Musculoskele-tal ultrasound. 2nd edition. St. Louis (MO):Mosby; 2001.

[9] Bureau NJ, Chhem RK, Cardinal E. Musculoskel-etal infections: US manifestations. Radiographics1999;19(6):1585–92.

[10] Goldenberg DL. Septic arthritis. Lancet 1998;351(9097):197–202.


[11] Knights EM. Infectious arthritis. J Foot Surg1982;21(3):229–33.

[12] Ryan MJ, Kavanagh R, Wall PG, et al. Bacterialjoint infections in England and Wales: analysisof bacterial isolates over a four-year period. Br JRheumatol 1997;36(3):370–3.

[13] Deesomchok U, Tumrasvin T. Clinical study ofculture-proven cases of nongonococcal arthritis.J Med Assoc Thai 1990;73(11):615–23.

[14] Le Dantec L, Maury F, Flipo RM, et al. Peripheralpyogenic arthritis. A study of one hundred se-venty-nine cases. Rev Rhum 1996;63(2):103–10.

[15] Keiser H, Ruben FL, Wolinsky E, et al. Clinicalforms of gonococcal arthritis. N Engl J Med1968;279(5):234–40.

[16] Resnick D. Osteomyelitis, septic arthritis, andsoft tissue infection: organisms. Diagnosis ofBone and Joint Disorders, vol 4. 3rd edition.Philadelphia: WB Saunders; 1995.

[17] Morgan DS, Fisher D, Merianos A, et al. An18-year clinical review of septic arthritis fromtropical Australia. Epidemiol Infect 1996;117(3):423–8.

[18] Masi AT, Eisenstein BI. Disseminated gonococcalinfection and gonococcal arthritis, II: clinicalmanifestations, diagnosis, complications, treat-ment and prevention. Semin Arthritis Rheum1981;10(3):173–97.

[19] Shirtliff ME, Mader JT. Acute septic arthritis. ClinMicrobiol Rev 2002;15(4):527–44.

[20] Kaandorp CJ, Van Schaardenburg D, Krijen P,et al. Risk factors for septic arthritis in patientswith joint disease. A prospective study. ArthritisRheum 1995;38(12):1819–25.

[21] Breidahl WH, Newman JS, Taljanovic MS, et al.Power Doppler sonography in the assessmentof musculoskeletal fluid collections. AJR Am JRoentgenol 1996;166(6):1443–6.

[22] Zawin JK, Hoffer FA, Rand FF, et al. Joint effusionin children with an irritable hip: US diagnosisand aspiration. Radiology 1993;187(2):459–63.

[23] Gordon JE, Huang M, Dobbs M, et al. Causes offalse-negative ultrasound scans in the diagnosisof septic arthritis of the hip in children. J PediatrOrthop 2002;22(3):312–6.

[24] Masini MA, Maguire JH, Thornhill TS. Infectedtotal knee arthroplasty. St. Louis (MO): Mosby-Year Book; 1994.

[25] Rand JA, Bryan RS. Reimplantation for thesalvage of an infected total knee arthroplasty.J Bone Joint Surg Am 1983;65(8):1081–6.

[26] Pandey R, Berendt AR, Athanasou NA. Histolog-ical and microbiological findings in noninfectedand infected revision arthroplasty tissues. TheOSIRIS collaborative study group. Oxford skele-tal infection research and intervention service.Arch Orthop Trauma Surg 2000;120(10):570–4.

[27] Segawa H, Tsukayama DT, Kyle RF, et al. Infec-tion after total knee arthroplasty. A retrospectivestudy of the treatment of eighty-one infections.J Bone Joint Surg Am 1999;81(10):1434–45.

[28] Steckelberg JM, Osmon DR. Prosthetic joint in-fections. 3rd edition. Washington, DC: AmericanSociety for Microbiology; 2000.

[29] Zimmerli W, Trampuz A, Ochsner PE. Prostheticjoint infections. N Engl J Med 2004;351(16):1645–54.

[30] Sperling JW, Kozak TK, Hanssen AD, et al. Infec-tion after shoulder arthroplasty. Clin OrthopRelat Res 2001;(382):206–16.

[31] Harris WH, Sledge CB. Total hip and total kneereplacement. N Engl J Med 1990;323(12):801–7.

[32] NIH Consensus Development: panel on total hipreplacement. NIH consensus conference: total hipreplacement. JAMA 1995;273:1950–6.

[33] Giulieri SG, Graber P, Ochsner PE, et al. Manage-ment of infection associated with total hip arthro-plasty according to a treatment algorithm.Infection 2004;32(4):222–8.

[34] Schafroth M, Zimmerli W, Brunazzi M, et al. In-fections. Berlin: Springer-Verlag; 2003.

[35] Nelson JP. Deep infection following total jointreplacement. J Bone Joint Surg Am 1982;64(7):1114.

[36] Peersman G, Laskin R, Davis J, et al. Infection intotal knee replacement: a retrospective review of6489 total knee replacements. Clin Orthop RelatRes 2001;(392):15–23.

[37] Schmalzried TP, Amstutz HC, Au MK, et al. Etiol-ogy of deep sepsis in total hip arthroplasty. Thesignificance of hematogenous and recurrentinfections. Clin Orthop Relat Res 1992;(280):200–7.

[38] Trampuz A, Hanssen AD, Osmon DR, et al. Sy-novial fluid leukocyte count and differential forthe diagnosis of prosthetic knee infection. Am JMed 2004;117(8):556–62.

[39] Loyer EM, DuBrow RA, David CL, et al. Imagingof superficial soft tissue infections: sonographicfindings in cases of cellulitis and abscess. AJRAm J Roentgenol 1996;166(1):149–52.

[40] Canoso JJ, Barza M. Soft tissue infections.Rheum Dis Clin North Am 1993;19(2):293–309.

[41] Jeffrey RBJ, Laing FC, Schechter WP, et al. Acutesuppurative tenosynovitis of the hand: diagnosiswith US. Radiology 1987;162(3):741–2.

[42] Santiago Restrepo C, Gimenez CR, McCarthy K.Imaging of osteomyelitis and musculoskeletalsoft tissue infections: current concepts. RheumDis Clin North Am 2003;29(1):89–109.

[43] Howard CB, Einhorn M, Dagan R, et al. Ultra-sound in diagnosis and management of acutehaematogenous osteomyelitis in children. Brit-ish Editorial Society of Bone and Joint Surgery1993;75(1):79–82.

[44] Mah ET, LeQuesne GW, Gent RJ, et al. Ultrasonicfeatures of acute osteomyelitis in children. J BoneJoint Surg Br 1994;76(6):969–74.

[45] Chao H, Lin SJ, Huang YC, et al. Sonographicevaluation of cellulitis in children. J UltrasoundMed 2000;19(11):743–9.


[46] Chao HC, Kong MS, Lin TY. Diagnosis of necro-tizing fasciitis in children. J Ultrasound Med1999;18(4):277–81.

[47] Keller MS. Musculoskeletal sonography in theneonate and infant. Pediatr Radiol 2005;35(12):1167–73.

[48] Asmar BI. Osteomyelitis in the neonate. InfectDis Clin North Am 1992;6(1):117–32.

[49] Tasx F, Oguz S, Bulut O, et al. Comparison of thediagnosis of plain radiography ultrasonographyand magnetic resonance imaging in early diag-nosis of acute osteomyelitis experimentallyformed on rabbits. Eur J Radiol 2005;56(1):107–12.

[50] Chao HC, Lin SJ, Huang YC, et al. Color Dopplerultrasonographic evaluation of osteomyelitis inchildren. J Ultrasound Med 1999;18(11):729–34.

[51] Kothari NA, Pelchovitz DJ, Meyer JS. Imaging ofmusculoskeletal infections. Radiol Clin NorthAm 2001;39(4):653–71.

[52] Struk DW, Munk PL, Lee MJ, et al. Imaging ofsoft tissue infections. Radiol Clin North Am2001;39(2):277–303.

[53] Christin L, Sarosi GA. Pyomyositis in NorthAmerica: case reports and review. Clin InfectDis 1992;15(4):668–77.

[54] Brook I. Pyomyositis in children, caused by anaer-obic bacteria. J Pediatr Surg 1996;31(3):394–6.

[55] Jackson MA, Nelson JD. Etiology and medicalmanagement of acute suppurative bone andjoint infections in pediatric patients. J PediatrOrthop 1982;2(3):313–23.

[56] Eich GF, Superti-Furga A, Umbricht FS, et al. Thepainful hip: evaluation of criteria for clinicaldecision-making. Eur J Pediatr 1999;158(11):923–8.

[57] Shaw BA, Kasser JR. Acute septic arthritis in in-fancy and childhood. Clin Orthop Relat Res1990;257:212–25.

[58] Howlett CR. The fine structure of the proximalgrowth plate and metaphysis of the avian tibia:endochondral osteogenesis. Am J Anat 1980;130(4):745–68.

[59] Nade S. Acute septic arthritis in infancy andchildhood. British Editorial Society of Boneand Joint Surgery 1983;65(3):234–41.

[60] Mallouh A, Talab Y. Bone and joint infection inpatients with sickle cell disease. J Pediatr Orthop1985;5(2):158–62.

[61] Dan M. Septic arthritis in young infants: clinicaland microbiologic correlations and therapeuticimplications. Rev Infect Dis 1984;6(2):147–55.

[62] Kocher MS, Zurakowski D, Kasser JR. Differenti-ating between septic arthritis and transient

synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone JointSurg Am 1999;81(12):1662–70.

[63] Rubaltelli L, Proto E, Salmaso R, et al. Sonogra-phy of abnormal lymph nodes in vitro: correla-tion of sonographic and histologic findings.AJR Am J Roentgenol 1990;155(6):1241–4.

[64] Papakonstantinou O, Bakantaki A, Paspalaki P,et al. High-resolution and color Doppler ultraso-nography of cervical lymphadenopathy in chil-dren. Acta Radiol 2001;42(5):470–6.

[65] Na DG, Lim HK, Byun HS, et al. Differentialdiagnosis of cervical lymphadenopathy: useful-ness of color Doppler sonography. AJR Am JRoentgenol 1997;168(5):1311–6.

[66] Steinkamp HJ, Wissgott C, Rademaker J, et al.Current status of power Doppler and colorDoppler sonography in the differential diagnosisof lymph node lesions. Eur Radiol 2002;12(7):1785–93.

[67] Wu CH, Shih JC, Chang YL, et al. Two-dimen-sional and three-dimensional power Doppler so-nographic classification of vascular patterns incervical lymphadenopathies. J Ultrasound Med1998;17(7):459–64.

[68] Benjamin DR. Granulomatous lymphadenitis inchildren. Arch Pathol Lab Med 1987;111(8):750–3.

[69] Ahuja A, Ying M, Evans R, et al. The applicationof ultrasound criteria for malignancy in differen-tiating tuberculous cervical adenitis from meta-static nasopharyngeal carcinoma. Clin Radiol1995;50(6):391–5.

[70] Ying M, Ahuja AT, Evans R, et al. Cervical lymph-adenopathy: sonographic differentiation be-tween tuberculous nodes and nodal metastasesfrom nonhead and neck carcinomas. J ClinUltrasound 1998;26(8):383–9.

[71] Asai S, Miyachi H, Suzuki K, et al. Ultrasono-graphic differentiation between tuberculouslymphadenitis and malignant lymph nodes.J Ultrasound Med 2001;20(5):533–8.

[72] Garcıa CJ, Varela C, Abarca K, et al. Regionallymphadenopathy in cat scratch disease: ultraso-nographic findings. Pediatr Radiol 2000;30(9):640–3.

[73] Ridder GJ, Richter B, Disko U, et al. Gray-scalesonographic evaluation of cervical lymphade-nopathy in cat scratch disease. J Clin Ultrasound2001;29(3):140–5.

[74] Gooding GA. Foreign bodies. Clin Diagn Ultra-sound 1995;30:99–111.

[75] Hill R, Conron R, Greissinger P, et al. Ultrasoundfor the detection of foreign bodies in humantissue. Ann Emerg Med 1997;29(3):353–6.



655

Peripheral Nerve AbnormalitiesCarlo Martinoli, MDa,*, Alberto Tagliafico, MDa,Stefano Bianchi, MDb, Gerd Bodner, MDc, Luca Padua, MDd,e,Angelo Schenone, MDf, Moshe Graif, MDg

- Normal anatomy and ultrasound scanningtechnique

- Anatomic variants- Inherited disorders and developmental

anomalies- Nerve involvement in medical diseases

- Entrapment syndromes- Traumatic injuries- Neurogenic tumors and intraneural

ganglia- References

Ultrasound (US) is being used more and more refers to the efficacy of nerve US as assessed with
frequently in various clinical settings to evaluatethe peripheral nervous system (eg, for inheriteddisorders, entrapment syndromes, traumas, andtumors), thus influencing the diagnosis and clinicalcare of the symptomatic patient [1–4]. Electrophys-iology has been the clinical ‘‘gold standard’’ fornerve assessment, but rapidly accumulating litera-ture exists comparing this modality with sonogra-phy [5–11]. In general, there is increasing insightamong neurologists that the use of electromyogra-phy and US is strongly converging regardless ofthe patient’s disorder and that combining thesetechniques will redefine the way that nerve diseasesare conceptualized and managed [12]. Whetherboth modalities should be performed in the samesession or be combined into a single methodologyor whether, in the end, neuroimaging will replaceneurophysiology is a matter of debate [9,13]. Re-garding the current state of the literature, if one
a Cattedra di Radiologia ‘‘R’’–DICMI, Universita di Genob Fondation et Clinique des Grangettes, Geneva, Switzec Department of Radiology, St. Bernard’s Hospital, Gibrd Istituto di Neurologia, Universita Cattolica del Sacro Ce Fondazione Don Carlo Gnocchi, Rome, Italyf Dipartimento di Neuroscienze, Oftalmologia e Genetig Department of Radiology, Tel Aviv Ichilov-Sourasky M* Corresponding author. Cattedra di Radiologia ‘‘R’’–DII-16132 Genova, Italy.E-mail address: [email protected] (C. Martinoli).


the Thornbury’s scale [14], most pathologies affect-ing nerves of the upper and lower extremities havepassed level I (technical efficacy) and, for themain tunnel syndromes, even level II (diagnostic-accuracy efficacy). An increasing number of studiesare now addressing level III (diagnostic-thinkingefficacy tier) to determine whether the imagingmodality helps strengthen or change the clinician’sdifferential diagnosis, and addressing level IV (ther-apeutic efficacy) to evaluate the impact of US onpatient management [9,15]. As a measure of theclinical impact of this modality, a recent prospectivestudy evaluated the outcomes of adding US to elec-trodiagnosis in the evaluation of mononeuropa-thies in a series of consecutive patients referred toan electromyographic laboratory for nerve impair-ment [9]. After 1 year of systematic assessment,the results of this study showed that US helped toconfirm or extend diagnostic findings in about

va, Genova, Italyrland

altar, UKuore, Policlinico Universitario, Rome, Italy

ca - DINOG, Universita di Genova, Genova, Italyedical Center, Tel Aviv, IsraelCMI. Universita di Genova, Largo Rosanna Benzi 8,




Martinoli et al656

half the cases by providing otherwise-undetectableanatomic information and, in 25% of cases, it con-tributed to redirect diagnosis and therapy, showingwhere and how to operate [9]. The opinion of theauthors is that we have only begun to ‘‘peel theonion’’ in this field. Given these considerations,the aim of this article is to review the main clinicalapplication of high-resolution US for evaluation ofpatients who have peripheral neuropathies. A briefintroductory note on normal anatomy and US scan-ning technique is also provided.

Normal anatomy and ultrasound scanningtechnique

With current high-resolution transducers, US candirectly image nerves and demonstrate their inter-nal structure, which consists of several hypoechoicstructures (fascicles) embedded in a hyperechoicbackground (epineurium) [16]. Generally, nervesare soft, flexible structures and may change shapefrom round to oval depending on the width ofthe anatomic passageways in which they run andthe conspicuousness of the perineural structuresthat lie in contact with them. In addition, they aremobile and can often be seen sliding over the sur-face of an artery, a tendon, or a muscle while apply-ing slight pressure with the probe or duringpatients’ movement. At US examination, nervesare poorly anisotropic structures: unlike tendonsand muscles, they do not need a perpendicular in-cidence of the US beam to be correctly imaged.Around the joints, nerves cross narrow osteofibroustunnels and may assume a more homogeneoushypoechoic appearance due to a tighter packageof fascicles and local reduction in the volume ofthe epineurium [17]. A careful US scanning

Fig. 1. Nerve echotexture. (A) Normal median nerve. Sh(arrowheads) at the midforearm demonstrates the fascicletures of different size separated by echogenic epineuriumShort-axis 15-7 MHz US image obtained at the distal radithe radial part (solid arrowheads) and the ulnar part (opnerve parts and the artery run as separate structures.

technique based on short-axis planes is essentialto recognize nerves throughout the limbs andextremities (Fig. 1A). Long-axis scans are less effec-tive for this purpose because the fascicles may beeasily confused with echoes from muscles and ten-dons coursing along the same plane. When difficul-ties arise in distinguishing small nerves fromadjacent small vessels, Doppler imaging may helpthe diagnosis. Although all nerves can be displayedin the extremities due to their superficial positionand absence of intervening bone, depiction of theperipheral nervous system is not possible every-where with US. Most cranial nerves, the nerve rootsexiting the dorsal, lumbar, and sacral spine, thesympathetic chains, and the splanchnic nerves inthe abdomen cannot be visualized due to a too-deep course or the interposition of bony structures.When nerves lie deeply, as often occurs in obesepatients, evaluation can be more difficult. In gen-eral, nerves are more easily depicted among musclesthan when surrounded by fat.

Anatomic variants

During a conventional examination of the periph-eral nervous system, several anatomic variants canbe recognized with US, such as a bifid median nervewith or without a persistent median artery of theforearm (Fig. 1B) [18–20]. In addition, variousextrinsic abnormalities along the course of a nerve,such as skeletal anomalies (ie, supracondylar pro-cess of the humerus and ligament of Struthers forthe median nerve) and the occurrence of accessoryor anomalous muscles, may be clinically relevantby predisposing nerves to compression. In thesecases, US can contribute to recognizing the causeof nerve dysfunction. Similarly, the congenital

ort-axis 15-7 MHz US image over the median nerves (open arrow) as well-circumscribed individual struc-. (B) Bifid median nerve and persistent median artery.

us reveals the median artery (arrow) located betweenen arrowheads) of a bifid nerve. Note that the two

Peripheral Nerve Abnormalities 657

absence of retinacula as it occurs at the cubital tun-nel level may cause ulnar nerve instability duringjoint motion. In this setting, dynamic scanning dur-ing full elbow flexion can allow continual depictionof the intermittent dislocation of the ulnar nerveover the medial epicondyle [21]. Dislocation ofa prominent medial head of the triceps muscle(snapping triceps syndrome) can occur in combina-tion with dislocation of the ulnar nerve [21].

Inherited disorders and developmentalanomalies

Some inherited and developmental anomalies ofthe peripheral nervous system, such as fibrolipom-atous hamartoma, Charcot-Marie-Tooth disease,and hereditary neuropathy with liability to pressurepalsies, can exhibit nerve abnormalities that aredetectable on US examination. In these disorders,US imaging may support clinical and electrophysi-ologic findings for a better understanding of the sta-tus and pathophysiology of the disease process.Fibrolipomatous hamartoma is a developmentaltumorlike nerve disorder related to accumulationof mature fat and fibroblasts in the epineuriumthat often presents during childhood and earlyadulthood. It involves the median nerve and, lesscommonly, lower extremity nerves and may beassociated with local gigantism of the hand orfoot related to bony overgrowth, fat proliferationin the soft-tissues, and nerve territory–orientedmacrodactyly, a condition known as ‘‘macrodystro-phia lipomatosa.’’ The US appearance of fibroli-pomatous hamartoma is stereotypic, reflecting itshistopathology with increased hyperechoic fatsurrounding slightly enlarged fascicles (Fig. 2)

Fig. 2. Fibrolipomatous hamartoma of the median nervenerve at the distal radius with T1-weighted SE MR imagingment of the median nerve (arrowheads). The nerve exhibitincreased interfascicular fatty tissue. ft, flexor tendons.

[22,23]. Charcot-Marie-Tooth disease is aninherited condition in which all nerves of thebody are hypertrophied due to the abnormalgrowth of Schwann cells. At US examination, nervesretain a normal fascicular echotexture but appearlarger than normal [8,24]. The most commonforms of disease include two autosomal dominanttypes (1A and 2, related to DNA duplication ofa region on chromosome-17 that codes for a myelinprotein) and an X-linked type (related to a mutationin the gene that codes for a gap-junction protein)[25]. With regard to genetics, patients who havetype 1A disease have significantly larger fasciclesthan patients who have other disease subtypes [8];however, no correlation exists between nerve or fas-cicle size and electrophysiologic features [8]. Thehereditary neuropathy with liability to pressurepalsies (tomaculous neuropathy) is another con-genital disorder in which a ‘‘sausage-shaped’’ mye-lin sheath swelling is responsible for multifocalnerve enlargement following trivial traumas[26,27]. US has proved able to recognize focal nerveswellings (tomacula) within osteofibrous tunnelsand along the course of nerves throughout theextremities [27].

Nerve involvement in medical diseases

As practice and knowledge in nerve US progresses,new perspectives on the application of this modal-ity to evaluate nerves in a variety of systemic andinfectious disorders in which they may be secondar-ily involved as a manifestation of the disease pro-cess are emerging. In this field, there is initial butinteresting experience in the use of US as a correlateof nerve conduction studies in rheumatologic

. Short-axis 17-5 MHz US image (A) over the mediancorrelation (B) reveals an abnormal fusiform enlarge-s thickened hypoechoic fascicles (arrow) embedded in

Martinoli et al658

disorders, diabetes, acromegaly, end-stage renal dis-ease, and leprosy. In many rheumatologic disorderssuch as rheumatoid arthritis, polyarteritis nodosa,and Wegener’s granulomatosis, degenerativechanges induced in large nerves by necrotizingangiopathy of small arteries are observed as a resultof vasculitis-related neuropathy, the so-called ‘‘mul-tiple mononeuropathy’’ [28]. Distinguishing thiscondition from symptoms related to local derange-ment of joints or entrapment neuropathies inwhich nerves pass adjacent to synovial joints (ie,cubital and tarsal tunnels, Guyon’s canal), syno-vial-sheathed tendons (ie, flexor tendons at thecarpal tunnel, flexor hallucis longus at the tarsaltunnel), or para-articular bursae (ie, iliopsoasbursa) may not be straightforward clinically. Inthis setting, US can help distinguish local compres-sive neuropathy from nonentrapment neuropathybased on the fact that multiple mononeuropathydoes not lead to an altered morphology of theaffected nerve like entrapment neuropathies do.Diabetic polyneuropathy, the most frequent formof neuropathy in the Western world, is character-ized by progressive course and severe complaints,ranging from sensory symptoms in the legs andfeet to weakness in the muscles of the feet [29].Recently, US demonstrated that the tibial nerve issignificantly swollen in diabetic patients who haveneuropathy at the tarsal tunnel level comparedthose who do not, a feature suggesting that chroniccompression may play a pathogenetic role in thiscondition [30,31]. In addition, US appears to beuseful in identifying early atrophy of small footmuscles in these patients, thereby predictingchanges in neurophysiologic parameters [32]. Inacromegaly, peripheral neuropathy is common. Inthis clinical context, patients complain of sensorydisturbances in their hands and feet, and at diseasepresentation, carpal tunnel syndrome occurs witha prevalence as high as 64% of cases [33]. USrevealed that acromegalic nerves are significantlyenlarged compared with those of normal subjects[34]. In contrast to focal neuropathies, the patternof nerve enlargement is diffuse and tends to be uni-formly distributed throughout the upper extremity[34]. In end-stage renal disease, amyloid arthropa-thy is a well-recognized complication of long-termhemodialysis treatment [35]. Clinically, this condi-tion manifests as a symmetric polyarthropathy withpain and stiffness and may be preceded by carpaltunnel syndrome related to extensive depositionof abnormal soft tissue within the tunnel, displac-ing the flexor tendons and compressing the mediannerve [3]. In leprosy (Hansen disease; a multifacetedinfectious disease caused by Mycobacterium leprae),nerves are specifically involved. Although in theWestern world this condition mainly affects

immigrants, it is endemic in developing countriesand, in itself, represents the most diffuse neuropa-thy worldwide. Clinically, leprosy can be dividedinto two polar forms—tuberculoid and leproma-tous—between which borderline forms exhibit anintermediate spectrum of phenotypes [36]. Intuberculoid leprosy, there is a strong immuneresponse, leading to aggressive infiltration of epi-thelioid and lymphoid cells into the nerve sub-stance; in the lepromatous type, the host responseis more indolent, with better preservation of thenerve architecture. Transition toward a higher-resistance form of leprosy may produce episodesof acute neuritis, during which a nerve segmentmay become intensely painful and tender, withrapid acceleration of the histopathologic and func-tional damage. In leprosy patients, US can revealmarkedly swollen nerves with loss of the fascicularechotexture (Fig. 3A, B) [37]. These changes are bet-ter appreciated in patients who have had repeatedepisodes of acute neuritis [37,38]. The onset ofacute neuritic phases may be predicted by detectionof intraneural hyperemia at Doppler imaging,a sign suggesting rapid progression of nerve damageand the need for steroid therapy (Fig. 3C) [37]. Re-cently, US-guided needle biopsy has been suggestedas a promising alternative to open nerve biopsy inpatients who have leprosy [39].

Entrapment syndromes

Based on US assessment, the nerves involved inentrapment syndromes can be arbitrarily groupedinto three main classes. The first includes largenerves such as the median, the ulnar, the radial,the sciatic, the peroneal, and the tibial, which areeasily imaged with US at the compression site (car-pal tunnel, cubital tunnel, spiral groove, fibular tun-nel, tarsal tunnel). In these cases, US evaluationdoes not necessarily require high-end technologybut can be performed with conventional equip-ment. The diagnosis is based on pattern recognitionanalysis, and at least for the carpal and the cubitaltunnels, nerve measurements (nerve cross-sectionalarea) can help quantify the US findings andenhance the examiner’s confidence. When examin-ing this nerve class, the US performance seems tobe nearly equivalent to that provided with MRimaging in terms of diagnostic information. Thesecond class includes small nerves (<2 mm) suchas the posterior and the anterior interosseous, themusculocutaneous, the sural, and the divisionalbranches of the ulnar and the peroneal—thedepiction of which requires high-end equipmentand high-frequency transducers. In these cases,quantitative measurements are not applied due tothe tiny size of the nerve bundles, and the diagnosis

Fig. 3. Acute neuritis in leprosy. Long-axis (A) and short-axis 17-5 MHz US images (B) over the ulnar nerve at theelbow in a patient who had borderline tuberculoid leprosy examined during the course of a reversal reactiondemonstrate high-grade swelling of the nerve (arrows) with smooth fusiform enlargement of individual fascicles(asterisks). ME, medial epicondyle. (C) Long-axis color Doppler 12-5 MHz US image shows dramatically increasedblood flow within endoneural vessels.


is exclusively based on pattern recognition analysis.In many cases, anatomic landmarks such as bonesand superficial vessels (ie, the small saphenousvein for the sural, the plantar vessels for the plantarnerves) are used to identify small nerves. Few stud-ies have compared the performance of US with MRimaging in depicting the pathology of these nerves;however, the authors believe that in experiencedhands, US equipped with an appropriate transduceris often superior to and more confident than MRimaging in identifying focal compressive abnormal-ities. Compared with MR imaging, the main advan-tages of US are related to its capability to betterseparate distal nerves from adjacent vessels, and inmany instances, the process of MR imaging diagno-sis based on evaluation of muscle changes cannotbe realized because many distal branches are purelysensory. The third class includes nerves that arepoorly detectable or nondetectable with US due toa too-small size, a too-deep course, or interveningbone. Tiny nerves such as the saphenous in theleg and even large nerves such as the sciatic andthe femoral in their intrapelvic course belong tothis latter class. When nerves cannot be directlyimaged in the extremities, US can suggest a nerveproblem based on the indirect evaluation of theinnervated muscles. Denervation atrophy as seenon US leads to a hyperechoic appearance of theaffected muscle, but this sign is not as accurate asMR imaging in differentiating the process of early

denervation related to intramuscular extracellularedema from fatty atrophy [40].

Considering the first two classes, there are severalsites of nerve entrapment that are amenable to USexamination in the upper and lower extremities.These sites include the supraspinous-spinoglenoidnotches for the suprascapular nerve and the quadri-lateral space for the axillary nerve [41]; the spiralgroove of the humerus for the radial nerve [42–44]; the supinator area for the posterior inteross-eous nerve [45,46]; the cubital tunnel and Guyon’scanal for the ulnar nerve [3,5,6,41,47,48]; the mid-dle forearm for the anterior interosseous nerve [49];the carpal tunnel for the median nerve [3,10,48,50–55]; the fibular head and neck for the peronealnerve [3]; the tarsal tunnel for the tibial nerve[3,30]; and the intermetatarsal spaces for the inter-digital nerves [56–58]. Regardless of the entrap-ment site and the fact that the involved nerve maypertain to the first or the second class, the US signsof compressive neuropathy are stereotypic [3]. Thecompressed nerve exhibits a fusiform swelling thatappears maximal in proximity to the compressionpoint where the nerve suddenly flattens (Figs. 4–6). On the basis of these features, US is an accuratemeans of identifying the exact level of compressionas located just ahead of the thickened portion of thenerve. Intraneural venous congestion and edemaare mainly responsible for the nerve enlargementthat occurs in the early phases of compression

Fig. 4. Carpal tunnel syndrome. (A) Long-axis 17-5 MHz US image over the ventral wrist shows abrupt flattening(open arrowheads) of the median nerve in the carpal tunnel and swelling (straight arrows) of the nerve portionproximal to the proximal edge of the retinaculum (curved arrow); left side of image is distal. Short-axis 17-5 MHzUS images obtained at the distal radius (B) and the distal carpal tunnel (C). By comparing the two levels of USexamination, a marked flattening of the nerve size can be appreciated at the point where the nerve (solidarrows and open arrowheads) passes deep to the flexor retinaculum (solid arrowheads). ft, flexor tendons.

Martinoli et al660

[59]. The increased water content causative fornerve swelling appears directly correlated with a cas-cade of events that ultimately leads to axon loss(axonotmesis) [6,60]. This finding is reinforced bythe evidence of a positive correlation between thenerve area and the severity of electromyographicfindings [6,10,54]. Although nerve flatteningshould be reasonably considered the most appro-priate sign of compression, quantitative measure-ment of nerve thickening by means of the ellipseformula to calculate the maximum cross-sectionalarea has proved to be the most consistent criterionfor the diagnosis [55,61,62]. In addition, the nerveechotexture may become uniformly hypoechoicwith loss of the fascicular pattern due to swellingof the fascicles and reduced echogenicity of the epi-neurium; in general, these changes occur graduallyand become more severe as the nerve progressestoward the site of compression [3]. The outerboundaries of the nerve, which are normallyundefined due to a continuum between the epineu-rium and the perineural fat, become clear-cut, andthere may be reduced mobility of the nerve withinthe tunnel [63]. Intraneural hyperemia can alsobe appreciated with Doppler techniques reflectinglocal disturbances in the microvasculature that

accompany the compressive context [3]. At the car-pal tunnel level, the information provided byDoppler imaging seems to be a good predictor ofmedian nerve entrapment [62]. In longstandingcompressions, irreversible intraneural fibrosis mayoccur. Unlike what is observed in early disease,nerves with fibrotic changes tend to remain swollenafter decompressive surgery and show poor func-tional improvement.

Traumatic injuries

Nerve trauma derives from three main pathome-chanisms—stretching, contusion, and penetratingwounds—that may occur alone or in combination.Stretching injuries are usually the result of repetitivesprain, strain lesions, or overuse. The most relevantof these take place at the brachial plexus level fol-lowing motor vehicle accidents [15,63,64] or inthe popliteal space for the peroneal nerve followinghigh-grade sprains, knee dislocation, or fractures[65]. In severe traction injury, there may be lacera-tion of the nerve, with interruption and retractionof the fascicles that assume a wavy course (Figs. 7and 8A) [63–65]. The outer nerve sheath may beintact or disrupted. When the impact of the traction

Fig. 5. Cubital tunnel syndrome. Long-axis (A) and short-axis 12-5 MHz US images obtained at the condylargroove (B) and within the cubital tunnel (C) in a patient who had ulnar neuropathy and post-traumatic changesin the elbow resulting in cubitus valgus. An abrupt narrowing of the ulnar nerve (UN) is observed between thethickened floor of the tunnel (arrows) and the cubital retinaculum (arrowheads). At the condylar groove level,the compressed ulnar nerve appears swollen and hypoechoic with absent fascicular pattern.

Fig. 6. Posterior interosseous neuropathy. Long-axis12-5 MHz US image over the posterior interosseousnerve (PIN) at the elbow in a patient who had fin-ger-drop demonstrates a thickened hyperechoic ar-cade of Frohse (open arrow), causing distortion andcompression of the posterior interosseous nerve asit enters the supinator tunnel (arrowheads). Proximalto the arcade, the nerve (solid arrows) appears mark-edly swollen. BrRad, brachioradialis muscle.


force causes a partial nerve tear, a spindle neuromacan develop as an irregular fusiform hypoechoicswelling along the course of the nerve without evi-dence of nerve discontinuity (Fig. 8B). In mildcases, the neuroma may involve part of the fascicles,with the cross-sectional area of the nerve appearingnormal or only slightly swollen. Contusion injuriesmost often occur where nerves run alongside bonysurfaces or at sites of restricted mobility and aretherefore more vulnerable to external injuries. Inmost cases, these injuries are self-resolving and donot generate abnormal US findings. The most typi-cal involve the radial nerve at the spiral groove fol-lowing external compression or impingementagainst a fracture fragment, the common peronealnerve at the fibular head, or the deep peroneal nerveagainst the dorsal midfoot. These lesions lead to thedevelopment of a segmental fusiform thickening ofthe nerve at the contusion site. A peculiar type ofcontusion trauma may occur at the cubital tunnellevel in predisposed patients who have unstableulnar nerves. In these cases, the repeated frictionof the ulnar nerve against the medial epicondyleduring elbow flexion may cause nerve swellingand hypoechoic changes related to friction neuritis[21]. Penetrating wounds from sharp, metallic

Fig. 7. Brachial plexus injury. Long-axis 12-5 MHz US composite imageover the left brachial plexus nervesin a patient who had upper limbpalsy after a motorcycle accidentreveals complete interruption of theupper and middle trunks (openarrowheads), which end in a largesupraclavicular hematoma (asterisks).Distal to the clavicle, the retractedinjured nerves assume a wavy course(solid arrowheads). The star denotesthe cervical spine.

Martinoli et al662

objects or glass fragments may induce partial orcomplete interruption of the nerve fascicles, leadingto formation of traumatic neuromas. In completetears, terminal neuromas can be appreciated assmall hypoechoic masses in continuity with theopposite edges of the transected nerve [66]. Theiridentification is critical in the preoperative settingbecause the nerve ends may be displaced andretracted far from the injury site. When the nerveends are curled up, the hypoechoic neuroma mayencase the nerve stumps, mimicking a partial tear.In partial nerve tears, the neuroma may embedresected and unaffected fascicles, giving rise to a ho-mogeneous fusiform swelling of the nerve bundle,or it can involve the resected fascicles selectively,leaving the spared ones to run freely alongside themass. Overall, in nerve traumas, US may help toprovide information about the level and severity ofthe nerve damage and to define surgical candidates.Often, electrophysiology yields ambiguous findings,and deciding whether the patient should be oper-ated on early or managed conservatively may repre-sent a real dilemma for the surgeon [15,43]. Thissituation may be particularly true in minor nervelesions without significant axonal damage or when

Fig. 8. Peroneal nerve injury (two different cases). (A) Lona patient who had previous knee dislocation shows compend (arrows) of the retracted distal stump (arrowheads) oaxis 12-5 MHz US image of the popliteal fossa in a patisprain. A fusiform hypoechoic swelling of the nerve (arrowof a stretching trauma. Distally, the nerve (arrowheads) a

the nerve is impinged by fracture fragments orencased in a fibrous callus [66]. In the postoperativesetting, US allows a reliable postoperative evalua-tion of the repaired nerve. After internal neurolysisto treat partial nerve tears, US may check the statusof the fascicles and exclude a newly formed postop-erative scar close to the nerve surface. In nerve recon-structive surgery, irregular bulging of hypoechoictissue at the anastomosis, possibly involving oneside of the graft, indicates poor fusion of the nerveedges, which is related to excessive tension or defec-tive surgery [66–68]. In addition, secondary scarafter surgery may limit translation of the nerve rela-tive to the adjacent soft tissues during joint motion,possibly leading to persistent symptoms with painand functional deficit. Under these circumstances,US can yield reliable information with respect toplanning a further surgical look [68].

Neurogenic tumors and intraneural ganglia

Most peripheral nerve tumors originate from neuralor Schwann cells, including two main benignforms—the schwannoma (also known as neurinomaor neurilemmoma) and the neurofibroma—and

g-axis 12-5 MHz US image over the popliteal fossa inlete disruption of the peroneal nerve. Note the bluntf the nerve and the empty sheath (asterisks). (B) Long-ent who had peroneal nerve palsy following a knees) can be appreciated in the popliteal fossa as a resultppears normal in size.


the malignant peripheral nerve sheath tumor [22].The US diagnosis of these tumors basically relieson detection of a soft tissue mass in continuitywith a nerve at its proximal and distal poles [69–72]. This feature may be assessed with difficulty incases of tumors arising from small nerves and cannotbe appreciated when the mass takes its origin fromsuperficial (subcutaneous) or too-distal nerves.In this latter instance, nerve tumors areindistinguishable from other soft tissue masses.Unlike neurofibromas, schwannomas have beendescribed as eccentrically placed ovoid masses[22,70] but in many cases, they appear to have cen-tral continuity with the involved nerve [72]. The ec-centric growth of Schwannomas is related to the factthat the tumor develops from an individual fasciclethat remains in axis with the bulk of the mass,whereas the spared fascicles are displaced eccentri-cally (Fig. 9A). Large masses may contain calcifiedfoci and internal degenerative cystic changes(Fig. 9B). On the contrary, neurofibromas are inti-mately associated with the parent nerve, developingin a fusiform rather than a globoid fashion. They

Fig. 9. Peripheral nerve sheath tumors: spectrum of US apimage over the ulnar nerve in the arm demonstrates a h(arrows) at its proximal and distal poles. The tumor is cwhereas the other fascicles (open arrowheads) remain un(B) Schwannoma. Long-axis 12-5 MHz US image over theappearance of the mass, which contains some hyperechoic12-5 MHz US image of the bicipital sulcus in a patientneurofibromas arising from the fascicles of the medianthe biggest lesion, the ‘‘target sign,’’ consisting of a largechoic halo (2), can be appreciated.

may exhibit a ‘‘target sign’’ consisting of a hyperechoicfibrous center surrounded by a peripheral hypoe-choic rim of myxomatous tissue (Fig. 9C) [70,73].Despite these differences, most peripheral nervesheath tumors present as homogeneous hypoechoicmasses with posterior acoustic enhancement, anda clear separation among tumor histotypes orbetween benign and malignant forms is unfeasiblewith this technique [72]. In plexiform types, neurofi-bromas and schwannomas may involve a long nervesegment and its branches, leading to diffuse tortuousthickening of the affected nerve [22]. Widespreadnerve involvement by neurofibromas may be seenin type 1 neurofibromatosis (Recklinghausen’sdisease). Overall, in primary nerve tumors, US cancontribute to preoperative assessment of the extentof disease, defining the relationship of the tumorwith adjacent vessels and muscles, and assisting insurgical planning.

On occasion, other non-neural sheath peripheralnerve masses may originate from, infiltrate, or ad-here to a nerve, including lipomatous lesions, para-gangliomas, hemangiomas, lymphomas, extrinsic

pearances. (A) Schwannoma. Long-axis 12-5 MHz USypoechoic oval mass (T) in continuity with the nerveonnected with a swollen fascicle (solid arrowheads),affected and displaced at the periphery of the mass.superficial peroneal nerve reveals a heterogeneous

foci (arrows) reflecting calcific deposits. (C) Transversewho had type 1 neurofibromatosis shows multiple

nerve (dotted line) and ulnar nerve (dashed line). Inhyperechoic center (1) surrounded by a thin hypoe-

Fig. 10. Peroneal intraneural ganglion. Transverse 17-5 MHz US image over the posterolateral knee (A) with fat-suppressed T2-weighted MR imaging correlation (B) demonstrates a ganglion cyst (asterisks) expandingbetween the outer nerve sheath (dashed line) and the fascicles (arrows). The ganglion can be differentiatedfrom the nerve substance based on its cystic structure. MR imaging correlation demonstrates a large ganglion(solid arrows) arising from the anterior aspect of the superior tibiofibular joint. The bulk of the ganglioncommunicates with the main trunk of the nerve (open arrows) through a long tubular process (arrowheads)representing the articular branch of the peroneal nerve. The articular branch runs deep to the extensor digito-rum longus muscle (edl) and peroneus longus muscle (pl). Note signs of denervation atrophy of the tibialisanterior muscle (ta).

Martinoli et al664

soft tissue neoplasms, and ganglion cysts [73,74].Intraneural ganglia are the most common. Theyappear as elongated cystic masses contained withinthe nerve sheath that grow within the epineurium,leading to severe nerve dysfunction (Fig. 10) [3].The pathogenesis of these cysts has been extensivelystudied and it is now accepted that the fluid pene-trates the nerve from an adjacent joint through anarticular (capsular) branch (see Fig. 10B) [75].The fluid is pumped within the articular branchthrough small capsular openings and, after exitingthe joint space, progresses upstream, dissectingthe epineurium, to reach the main nerve trunk[75,76]. At the end, the cyst shows an elongatedshape that closely recalls the course of the affectednerve. The superior tibiofibular joint is particularlypredisposed to generate intraneural ganglia. Thecysts can involve the peroneal and the tibial nerves,using the articular branches provided by thesenerves as conduits to carry fluid [75–77]. Intraneu-ral ganglia do not have a fibrous capsule ora synovial lining and must be differentiated fromthe more common extraneural (intramuscular)ganglia [78].

References

[1] Martinoli C, Bianchi S, Derchi LE. Tendon andnerve sonography. Radiol Clin North Am 1999;37:691–711.

[2] Keberle M, Jennett M, Kenn W, et al. Technicaladvances in ultrasound and MR imaging ofcarpal tunnel syndrome. Eur Radiol 2000;10:1043–50.

[3] Martinoli C, Bianchi S, Gandolfo N, et al. US ofnerve entrapments in osteofibrous tunnels of theupper and lower limbs. Radiographics 2000;20:199–217.

[4] Thain LMF, Downey DB. Sonography of periph-eral nerves: technique, anatomy, and pathology.Ultrasound Q 2002;18:225–45.

[5] Beeckman R, Schoemaker MC, Van der Plas JP,et al. Diagnostic value of high-resolution sonog-raphy in ulnar neuropathy at the elbow. Neurol-ogy 2004;62:767–73.

[6] Beeckman R, Van der Plas JP, Uitdehaag BM,et al. Clinical, electrodiagnostic and sonographicstudies in ulnar neuropathy at the elbow. MuscleNerve 2004;30:202–8.

[7] Beeckman R, van den Berg LH, Franssen H, et al.Ultrasonography shows extensive nerve


enlargements in multifocal motor neuropathy.Neurology 2003;30:202–8.

[8] Martinoli C, Schenone A, Bianchi S, et al.Sonography of median nerve in Charcot-Marie-Tooth disease. AJR Am J Roentgenol 2002;178:1553–6.

[9] Padua L, Aprile I, Pazzaglia C, et al. Contributionof ultrasound in a neurophysiological lab indiagnosing nerve impairment: a one-year system-atic assessment. J Clin Neurophysiol 2007;118:1410–6.

[10] Kele H, Verheggen R, Bittermann HJ, et al. Thepotential value of ultrasonography in the evalua-tion of carpal tunnel syndrome. Neurology 2003;61:389–91.

[11] Wong SM, Griffith JF, Hui ACF, et al. Carpaltunnel syndrome: diagnostic usefulness ofsonography. Radiology 2004;232:93–9.

[12] Walker FO. The four horsemen of the oscillo-scope: dynamic ultrasound, static ultrasound,electromyography and nerve conduction studies.J Clin Neurophysiol 2007;118:1177–8.

[13] Vucic S, Cordato DJ, Yiannikas C, et al. Utility ofmagnetic resonance imaging in diagnosis ulnarneuropathy at the elbow. J Clin Neurophysiol2006;117:590–5.

[14] Thornbury JR. Clinical efficacy of diagnosticimaging: love or leave it. AJR Am J Roentgenol1994;162:1–8.

[15] Gruber H, Glodny B, Galiano K, et al. High-resolution ultrasound of the supraclavicularbrachial plexus: can it improve therapeuticdecisions in patients with plexus trauma? EurRadiol 2007;17:1611–20.

[16] Silvestri E, Martinoli C, Derchi LE, et al. Echotex-ture of peripheral nerves: correlation between USand histologic findings and criteria to differenti-ate tendons. Radiology 1995;197:291–6.

[17] Sheppard DG, Iyer RB, Fenstermacher MJ.Brachial plexus: demonstration at US. Radiology1998;208:402–6.

[18] Propeck T, Quinn TJ, Jacobson JA, et al. Sonogra-phy and MR imaging of bifid median nerve withanatomic and histologic correlation. AJR Am JRoentgenol 2000;175:1721–5.

[19] Iannicelli E, Chianta GA, Salvini V, et al. Evalua-tion of bifid median nerve with sonography andMR imaging. J Ultrasound Med 2000;19:481–5.

[20] Gassner EM, Schocke M, Peer S, et al. Persistentmedian artery in the carpal tunnel: color Dopp-ler ultrasonographic findings. J Ultrasound Med2002;21:455–61.

[21] Jacobson JA, Jebson PJL, Jeffers AW, et al. Ulnarnerve dislocation and snapping triceps syn-drome: diagnosis with dynamic sonography—report of three cases. Radiology 2001;220:601–5.

[22] Murphey MD, Smith WS, Smith SE, et al. Imag-ing of musculoskeletal neurogenic tumors:radiologic-pathologic correlation. Radiographics1999;19:1253–80.

[23] Chen P, Massengill A, Maklad N, et al. Nerveterritory-oriented macrodactyly: unusual cause

of carpal tunnel syndrome. J Ultrasound Med1996;15:661–4.

[24] Heinemeyer O, Reimers CD. Ultrasound ofradial, ulnar, median and sciatic nerves inhealthy subjects and patients with hereditarymotor and sensory neuropathies. UltrasoundMed Biol 1999;25:481–5.

[25] Schenone A, Mancardi GL. Molecular basis ofinherited neuropathies. Curr Opin Neurol1999;12:603–16.

[26] Verhagen WIM, Gabreels-Festen AA, vanWensen PJ, et al. Hereditary neuropathy withliability to pressure palsies: a clinical, electro-neurophysiological and morphological study.J Neurol Sci 1993;116:176–84.

[27] Beekman R, Visser LH. Sonographic detection ofdiffuse peripheral nerve enlargement in heredi-tary neuropathy with liability to pressure palsies.J Clin Ultrasound 2002;30:433–6.

[28] Said G, Lacroix C. Primary and secondary vascu-litic neuropathy. J Neurol 2005;252:633–41.

[29] Tesfaye S, Chaturvedi N, Eaton SE, et al. Vascularrisk factors and diabetic neuropathy. N Engl JMed 2005;352:341–50.

[30] Lee D, Dauphinee DM. Morphological and func-tional changes in the diabetic peripheral nerve:using diagnostic ultrasound and neurosensorytesting to select candidates for nerve decompres-sion. J Am Podiatr Med Assoc 2005;95:433–7.

[31] Semionow M, Alghoul M, Molski M, et al.Clinical outcome of peripheral nerve decompres-sion in diabetic and nondiabetic peripheralneuropathy. Ann Plast Surg 2006;57:385–90.

[32] Severinsen K, Obel A, Jakobsen J, et al. Atrophyof foot muscles in diabetic patients can be de-tected with ultrasonography. Diabetes Care2007;30:3053–7.

[33] Colao A, Ferone D, Marzullo P, et al. Systemiccomplications of acromegaly: epidemiology,pathogenesis and managment. Endocr Rev2004;25:102–52.

[34] Tagliafico A, Resmini E, Nizzo R, et al. Nerve ul-trasound in acromegaly. J Clin Endocrinol Metab2007, in press.

[35] Cobby MJ, Adler RS, Swartz R, et-al. Dialysis-related amyloid arthropathy: MR findings infour patients. AJR Am J Roentgenol 157: 1023–27.

[36] Ridley DS, Jopling WH. Classification of leprosyaccording to immunity: a five group system. Int JLepr 1996;34:255–73.

[37] Martinoli C, Derchi LE, Bertolotto M, et al. USand MR imaging of peripheral nerves in leprosy.Skeletal Radiol 2000;29:142–50.

[38] Fornage BD, Nerot C. Sonographic diagnosis oftuberculoid leprosy. J Ultrasound Med 1987;6:105–7.

[39] Lolge SJ, Morani AC, Chaubal NG, et al.Sonographically guided nerve biopsy. J Ultra-sound Med 2005;24:1427–30.

[40] Kullmer K, Sievers KW, Reimers CD, et al.Changes of sonographic, magnetic resonance

Martinoli et al666

tomographic, electromyographic, and histopath-ologic findings within a 2-month denervationperiod of examinations after experimentalmuscle denervation. Arch Orthop Trauma Surg1998;117:228–34.

[41] Martinoli C, Bianchi S, Pugliese F, et al. Sonogra-phy of entrapment neuropathies in the upperlimb (wrist excluded). J Clin Ultrasound 2004;32:438–50.

[42] Bodner G, Huber B, Schwabegger A, et al.Sonographic detection of radial nerve entrap-ment within a humerus fracture. J UltrasoundMed 1999;20:131–6.

[43] Bodner G, Buchberger W, Schocke M, et al.Radial nerve palsy associated with humeral shaftfracture: evaluation with US: initial experience.Radiology 2001;219:811–6.

[44] Rossey-Marec D, Simonet J, Beccari R, et al.Ultrasonographic appearance of idiopathicradial nerve constriction proximal to the elbow.J Ultrasound Med 2004;23:1003–7.

[45] Bodner G, Harpf C, Meirer R, et al. Ultrasono-graphic appearance of supinator syndrome.J Ultrasound Med 2002;21:1289–93.

[46] Chien AJ, Jamadar DA, Jacobson JA, et al. Sonog-raphy and MR imaging of posterior interosseousnerve syndrome with surgical correlation. AJRAm J Roentgenol 2003;181:219–21.

[47] Okamoto M, Abe M, Shirai H, et al. Diagnosticultrasonography of the ulnar nerve in cubitaltunnel syndrome. J Hand Surg [Br] 2000;5:499–502.

[48] Bianchi S, Montet X, Martinoli C, et al. High-resolution sonography of compressive neuropa-thies of the wrist. J Clin Ultrasound 2004;32:451–61.

[49] Hide IG, Grainger AJ, Naisby GP, et al. Sono-graphic findings in the anterior interosseousnerve syndrome. J Clin Ultrasound 1999;27:459–64.

[50] Buchberger W, Judmaier W, Birbamer G, et al.Carpal tunnel syndrome: diagnosis with high-resolution sonography. AJR Am J Roentgenol1992;159:793–8.

[51] Buchberger W, Schon G, Strasser K, et al. High-resolution ultrasonography of the carpal tunnel.J Ultrasound Med 1991;10:531–7.

[52] Kotevoglu N, Gulbahce-Saglam S. Ultrasoundimaging in the diagnosis of carpal tunnelsyndrome and its relevance to clinical evalua-tion. Joint Bone Spine 2005;72:142–5.

[53] Koyuncuoglu HR, Kutluhan S, Yesildag A, et al.The value of ultrasonographic measurement incarpal tunnel syndrome in patients with negativeelectrodiagnostic tests. Eur J Radiol 2005;56:365–9.

[54] Ziswiler HR, Reichenbach S, Vogelin E, et al.Diagnostic value of sonography in patientswith suspected carpal tunnel syndrome:a prospective study. Arthritis Rheum 2005;52:304–11.

[55] Duncan I, Sullivan P, Lomas F. Sonography inthe diagnosis of carpal tunnel syndrome. AJRAm J Roentgenol 1999;173:681–3.

[56] Read JW, Noakes JB, Kerr D, et al. Morton’s meta-tarsalgia: sonographic findings and correlatedhistopathology. Foot Ankle Int 1999;20:153–61.

[57] Redd RA, Peters VJ, Emery SF, et al. Mortonneuroma: sonographic evaluation. Radiology1989;171:415–7.

[58] Quinn TJ, Jacobson JA, Craig JG, et al. Sonogra-phy of Morton’s neuromas. AJR Am J Roentgenol2000;174:1723–8.

[59] Sugimoto H, Miyaji N, Ohsawa T. Carpal tunnelsyndrome: evaluation of median nerve circula-tion with dynamic contrast-enhanced MR imag-ing. Radiology 1994;190:459–66.

[60] Powell HC, Myers RR. Pathology of experimentalnerve compression. Lab Invest 1986;55:91–100.

[61] Bargfrede M, Schwennicke A, Tumani H, et al.Quantitative ultrasonography in focal neuropa-thies as compared to clinical and EMG findings.Eur J Ultrasound 1999;10:21–9.

[62] Mallouhi A, Pultzl P, Trieb T, et al. Predictors ofcarpal tunnel syndrome: accuracy of gray-scaleand color Doppler sonography. AJR Am J Roent-genol 2006;186:1240–5.

[63] Nakamichi K, Tachibana S. Restricted motion ofthe median nerve in carpal tunnel syndrome.J Hand Surg [Br] 1999;20:460–4.

[64] Shafighi M, Gurunluoglu R, Ninkovic M, et al.Ultrasonography for depiction of brachial plexusinjury. J Ultrasound Med 2002;22:631–4.

[65] Gruber H, Peer S, Meirer R, et al. Peroneal nervepalsy associated with knee luxation: evaluationby sonography—initial experience. AJR Am JRoentgenol 2005;185:1119–25.

[66] Peer S, Bodner G, Mairer R, et al. Examination ofpostoperative peripheral nerve lesions with high-resolution sonography. AJR Am J Roentgenol2001;177:415–9.

[67] Graif M, Seton A, Nerubali J, et al. Sciatic nerve:sonographic evaluation and anatomic-pathologicconsiderations. Radiology 1991;18:405–8.

[68] Peer S, Harpf C, Willeit J, et al. Sonographicevaluation of primary peripheral nerve repair.J Ultrasound Med 2003;22:1317–22.

[69] Fornage BD. Peripheral nerves of the extremities:imaging with US. Radiology 1988;167:179–82.

[70] Lin J, Martel W. Cross-sectional imaging ofperipheral nerve sheath tumors: characteristicsigns on CT, MR imaging, and sonography. AJRAm J Roentgenol 2001;176:75–82.

[71] Beggs I. Sonographic appearances of nervetumors. J Clin Ultrasound 1999;27:363–8.

[72] Reynolds DL Jr, Jacobson JA, Inampudi P, et al.Sonographic characteristics of peripheral nervesheath tumors. AJR Am J Roentgenol 2004;182:741–4.

[73] Gruber H, Glodny B, Bendix N, et al. High-resolution ultrasound of peripheral neurogenictumors. Eur Radiol 2007;17:2880–8.


[74] Chatillon CE, Guiot MC, Jacques L. Lipomatous,vascular and chondromatous benign tumors ofthe peripheral nerves. Neurosurg Focus 2007;22:1–8.

[75] Spinner RJ, Atkinson JL, Tiel RL. Peroneal intra-neural ganglia: the importance of the articularbranch. A unifying theory. J Neurosurg 2003;99:330–43.

[76] Spinner RJ, Amrami KK, Rock MG. The use ofMR arthrography to document an occult jointcommunication in a recurrent peroneal

intraneural ganglion. Skeletal Radiol 2005;35:172–9.

[77] Spinner RJ, Mokhtarzadeh A, Schiefer TK, et al.The clinico-anatomic explanation for tibialintraneural ganglion cysts arising from thesuperior tibiofibular joint. Skeletal Radiol 2007;36:281–92.

[78] Bianchi S, Abdelwahab IF, Kenan S, et al.Intramuscular ganglia arising from the superiortibiofibular joint: CT and MR evaluation. SkeletalRadiol 1995;24:253–6.



669

Soft Tissue Foreign Bodies:Sonographic Diagnosis andTherapeutic ManagementWilliam E. Shiels II, DOa,b,*

- Sonographic detection, localization, andcharacterization of foreign bodies

- Foreign body removalPatient care and sedationForceps dissection and removal procedure

- General technical considerationsPitfalls

- Outcomes- Summary- References

Soft tissue foreign bodies are a common clinicalproblem in both children and adults [1]. Most for-eign bodies in the soft tissue are impaled as a resultof low-velocity trauma during domestic activity andinvolve the superficial soft tissues. Most low-veloc-ity foreign bodies can be removed directly withoutthe need for image guidance. Objects embeddedin deep soft tissues at high velocity usually areseen in occupational settings, as a result ofweapons, or during activities of war, with few re-quiring removal. In this article, the focus is on civil-ian, non–combat-related foreign body injuries. Asa general rule, soft tissue foreign bodies require re-moval when they become symptomatic or developinfectious complications. Many superficial foreignbodies can be palpated and removed readily.When superficial abscesses develop around foreignbodies, an incision over the area often results inexpectoration of both the contained pus and theforeign body.

In prior years, consultation for radiologic supportin the management of soft tissue foreign bodiesmost frequently occurred after failed attempts atblind surgical removal or attempts to remove

a Department of Radiology, Nationwide Children’s Hospb The Ohio State University Medical Center, 410 W. 10th* Department of Radiology, Nationwide Children’s HospE-mail address: [email protected]


radiopaque foreign bodies with fluoroscopic guid-ance. In the experience the author and his col-leagues, most surgeons, emergency physicians,and primary care physicians acknowledge the fre-quent futility of attempts at blind removal of smallas well as deep foreign bodies. Similarly, the samephysicians readily admit the limitations of fluoro-scopic guidance for removal of radiopaque foreignbodies: radiation exposure to the patient and pro-vider and the difficulty imposed by two-dimen-sional visualization on the fluoroscope.

With the advent of meticulous sonographic tech-niques, high-resolution sonography is the main im-aging tool used for the detection and localization ofnon-radiopaque foreign bodies in soft tissue [1–5].Radiopaque foreign bodies most frequently are de-tected and grossly localized with plain radiographs.Sonography plays an expanding role in identifica-tion, characterization, and detailed three-dimen-sional localization with respect to vitalneurovascular structures and tendons. With the de-velopment and documented success of sonograph-ically guided techniques for removing foreignbodies from soft tissue, the radiology department

ital, 700 Children’s Drive, Columbus, OH 43205, USAAvenue, Columbus, OH 43210, USA

ital, 700 Children’s Drive, Columbus, OH 43205.




Shiels670

at the Nationwide Children’s Hospital frequentlyreceives primary consultations for ultrasound-guided removal of foreign bodies (USFBR). This ar-ticle is written in the context of the author’s clinicalexperience of more than 15 years in identifying, lo-calizing, and removing more than 400 foreign bod-ies in the soft tissues, bones, joints, tendons, facialstructures, and the orbit. This article focuses onthe management of soft tissue foreign bodies, in-cluding those in muscle, tendon, and intra-articularspaces and structures.

Sonographic detection, localization, andcharacterization of foreign bodies

In the author’s experience, sonography is used mostfrequently for primary detection, localization, andcharacterization of non-radiopaque foreign bodies,following initial evaluation with plain radiography.Occasionally, CT or MR imaging are performed ini-tially in the evaluation of an unresponsive soft tis-sue infection, with sonography providing moreaccurate detection, localization, and characteriza-tion of the offending foreign body.

Detection of soft tissue foreign bodies is per-formed with meticulous technique, using the high-est-resolution sonographic transducers available. Inthe search for embedded foreign bodies, high-fre-quency linear-array transducers (7–17 MHz) arethe most useful in detecting radiopaque and non-radiopaque foreign bodies ranging in size from0.5 mm to more than 10 mm in the transverse di-mension and with lengths as short as 2 mm. Metic-ulous scanning is critical for the successfuldetection of foreign bodies, because small foreignbodies can be missed easily with rapid, less carefulscanning. Thin, minimally echogenic foreign bod-ies such as wood fragments can be sonographicallysubtle and can be mistaken for a muscle fibril or fas-cial plane. Flexible acoustic standoff pads provideexcellent scanning support, especially in small

Fig. 1. Oblique crosscut artifact producing an artificially s(arrow). (B) Sonogram of the same needle (arrow) artificiaa sound beam not properly aligned along the full long a

extremities and edges of extremities, because thestandoff pads convert rounded surfaces and edgesinto broad, flat scanning surfaces. Especially helpfulis the ability of these flexible pads to allow visuali-zation of 270� of the surface area of the edge ofa small extremity (ie, the edge of the hand, foot,or finger). Alternatively, a thick layer of acoustictransmission gel may be used in place of a standoffpad.

In the initial search process, foreign bodies aredetected most easily when the sound beam strikesthe object in line with the longitudinal axis, delin-eating the full length of the foreign body. Fre-quently, initial insonation strikes in the transverseplane of the foreign body, revealing small linear for-eign bodies as foci that are more echogenic thansurrounding soft tissues. The sonographic responsedistal to the foreign body may be helpful in thetransverse plane, because metallic and glass objectsmay produce profound reverberation artifacts, cast-ing a trail of echogenicity deep to the surface of theforeign body; whereas other foreign bodies maycast acoustic shadows. The reverberation artifactfrom metal and glass is most pronounced whenthe sound beam strikes perpendicular to the longaxis of the object. When sonologists are familiarwith these sonographic details, foreign bodies aredetected readily even in the transverse plane.

Once a foreign body is detected, it is important toalign the sound beam with the long axis of the for-eign body, perpendicular to the superficial surfaceof the foreign body for maximal conspicuity anddefinition. Caution is advised to avoid the potentialpitfall of the ‘‘oblique cross-cut’’ artifact created byscanning oblique to the true long axis of the foreignbody, artifactually foreshortening the appearance ofthe foreign body (Fig. 1). Once the foreign body isfully defined, the sonologist can localize the foreignbody accurately with respect to surrounding struc-tures such as blood vessels, nerves, tendons, andcartilaginous and boney structures. This

hort foreign body. (A) Sonogram of a metallic needlelly shortened by the oblique crosscut of the needle byxis of the needle.

Soft Tissue Foreign Bodies 671

localization is important, because a foreign bodymay be embedded in cartilage, located deep toa joint capsule, or be adjacent to an important vas-cular structure.

The sonographic characterization of foreign bod-ies often is possible, given specific known responsesof foreign bodies to ultrasound (Fig. 2). In vivo, allsolid foreign bodies have inherent echogenicity,which is greater with objects such as metal, wood,glass, stone, and hard plastic (such as polycarbonateplastic). Soft plastic and rubber (eg, subcutaneoustunneled vascular catheters) may have low echoge-nicity because they can transmit sound more effec-tively than other solid objects. The reverberationartifacts created with sonography can differentiatemetal (straight and linear artifacts) and glass(oblique comet-tail artifacts). The oblique comet-tail artifacts seen with glass are based on the irregu-lar facets often encountered in glass foreign bodies.Thick wood and stone respond to insonation withdense posterior acoustic shadowing. Wood, whenthin and well hydrated, may reveal the internal cel-lulose architecture on direct long-axis insonation,with little or no posterior shadowing.

The response of surrounding tissues is of diag-nostic importance, because granulation tissue and

Fig. 2. Sonographic detection and characterization of soft(straight arrow) in muscle, with dense shadowing (curved awooden foreign body (marked by cursors) with no shadoreverberation artifact (arrowheads) in the transverse plathe longitudinal plane with an oblique lie without thebody (arrow) with reverberation artifact (curved arrow).

pus create hypoechoic zones or halos surroundingthe foreign body. Longstanding inflammation sur-rounding a foreign body produces a hypoechoic‘‘halo’’ of granulation tissue, with vascular in-growth demonstrated with color Doppler sonogra-phy (Fig. 3). If a surgeon or other physician haspreviously attempted removal unsuccessfully, thereoften is air in the soft tissues surrounding the for-eign body, limiting accurate definition of the re-tained object. In this instance, it is prudent todress the wound and, if possible, allow a few daysto pass for air absorption before repeat sonographicexamination. Interrogation of adjacent soft tissuesis essential for the preprocedural decision-makingand planning process; these issues are discussed ina later section.

Pitfalls have been encountered in the sono-graphic search for foreign bodies. In children, carti-laginous structures (such as the patella) with small,early ossification centers can be mistaken for anechogenic foreign body with a hypoechoic halo(Fig. 4). Plantar warts with subcutaneous edemaand scars may appear as mildly echogenic cutane-ous foreign bodies. Subcutaneous air may be mis-taken for a brightly echogenic foreign body suchas glass. In the moment of diagnostic enthusiasm

tissue foreign bodies. (A) Thick wooden foreign bodyrrow) caused by air in the wooden toothpick. (B) Thinwing. (C) Glass foreign body (arrow) with comet-tailne. (D) Glass foreign body (arrows) as in panel C in

reverberation artifact. (E) Metallic needle foreign

Fig. 3. Hypoechoic granulation tissue surrounding a thick wooden foreign body with posterior shadowing. (A)Longitudinal sonogram of granulation tissue halo (curved arrow) surrounding the embedded wood foreignbody (arrow). (B) Transverse view of wooden foreign body (arrow) shown in panel A with a hypoechoic granu-lation tissue halo (curved arrow) and posterior shadowing (arrowhead).

Shiels672

when one foreign body is detected, sonographersand sonologists are cautioned to continue a thor-ough search for multiple foreign body fragmentsin the injury site.

Localization may include preoperative verbal def-inition of anatomic coordinates for a surgeon and/or preoperative skin marking for surgical mapping.An additional means of preoperative localization isthe placement of localization wires with sono-graphic guidance. In the author’s practice, localiza-tion wires are used primarily for localization ofextremely thin and irregular wood or small glassfragments that may not be felt or seen by the oper-ating surgeon. As discussed in greater detail in a latersection, irregular wood fragments and thin glass

Fig. 4. Pitfall of early patellar ossification initially mistakenTransverse sonogram of the patella demonstrating a smaltion center) surrounded by hypoechoic material (patellardemonstrates this focus to be the early ossification cente

pieces may fragment during attempted sonographi-cally guided removal with forceps and may be re-moved best with an operative approach. Theauthor and colleagues have found that localizationwires provide excellent intraoperative guidance andare well accepted by surgeons. Radiologists notcomfortable with USFBR may find wire localizationto be an excellent way to support a surgeon withmore precise localization of a foreign body than ob-tained by verbal coordinates or skin marking. Local-ization needles are placed under sonographicguidance so that the hooked wire is deployed adja-cent to the deep surface and either the proximal ordistal tip of the foreign body (Fig. 5). In this fash-ion, the surgeon can follow the wire and encounter

as a foreign body in the knee of a 4-year-old girl. (A)l hyperechoic focus (arrow) (an early patellar ossifica-cartilage). (B) Lateral radiograph of the patient’s kneer (arrow) of the patella.

Fig. 5. Wire localization of soft tissue tree bark fragments in 11-year-old boy. The patient presented with massiveinfection and retained bark fragments 1 month after a tree branch was removed from his forearm in the emer-gency department. Fragments marked with Kopans-type hooked wires were removed successfully at surgery.The fragment marked with the retractable needle was not retrieved at surgery. (A) Sonogram demonstratingsmall bark fragments (arrows) in the forearm. (B) Kopans-type localization wire with hook (straight arrows)placed deep to the tip of a bark fragment (curved arrow). (C) Forearm radiograph demonstrating three Ko-pans-type wires (straight arrows) and one retractable wire (curved arrow). (D) Photograph of Kopans-typespring-hook localization wire.


the foreign body before reaching the hook. Inadults and children not requiring sedation, place-ment of localization wires is performed undersonographic guidance after the generous adminis-tration of local anesthesia to the depth of wirehook placement. Once the localization wire is inplace, the placement needle is removed, and the ex-posed wires are secured to the skin with gauze andtape dressing. With respect to hook type, both sin-gle-hook and dual retractable-hook wires havebeen used; the author prefers the single-hook wirefor more precise localization. The Kopans-type lo-calization wire provides a smaller target for surgicaldissection, whereas the retractable location wiresprovide a broad, rounded target. Additionally, thesharp hook on the Kopans-type wire allows the op-erator to secure the wire in place firmly with real-time sonographic guidance. Retractable localization

wires are unnecessary, because sonography allowsprecise placement of the localization needle and de-ployment of the wire hook.

Local anesthetic may play a dual role, both pro-viding anesthesia and enhancing the definition ofa subtle soft tissue foreign body. After the operativebed is infiltrated with local anesthesia, lidocainecan be injected with a small-gauge needle adjacentto the foreign body, clearly defining the foreignbody from the surrounding soft tissues.

Foreign body removal

Patient care and sedation

Sedation for foreign body removal usually is re-quired for small children or children unable to tol-erate a procedure under local anesthesia. Anexcellent sedation protocol includes a combination

Shiels674

of intravenous pentobarbital and fentanyl. Thisdrug combination is administered in a tailoredand titrated fashion, beginning with fentanyl,1 mg/kg, and pentobarbital, 2 to 3 mg/kg. The totaltitrated doses do not exceed 3 mg/kg for fentanyland 8 mg/kg for pentobarbital. In older children,midazolam, 0.1 mg/kg, may be substituted for pen-tobarbital. Patient sedation is accompanied by con-tinuous monitoring of heart rate and oximetry.General anesthesia rarely is required for foreignbody removal. For reasons of patient preparation,operator expertise, and the non-emergent natureof most foreign body injuries, patients in whomforeign bodies are not easily removed in the emer-gency department are referred to the interventionalradiology service for outpatient removal of a foreignbody.

Foreign body removal is performed safely in a so-nography suite, interventional radiology suite, or inthe operating theater. For echogenic foreign bodies,the interventional radiology suite is an ideal loca-tion, given the availability of both sonographyand fluoroscopy for image guidance, as needed.For example, removal of a metallic needle or radi-opaque glass fragment lying perpendicular to theskin surface may be performed best with sonogra-phy used for precise and effective local anestheticinjection in the operative bed and fluoroscopyused for removal guidance.

Local anesthesia is the single most important as-pect of the sedation/anesthesia component in for-eign body removal procedures. Lidocaine HCl 1%is administered most effectively in a generous fash-ion with sonographic guidance. With proper tech-nique, 25- to 30-gauge needles are visualizedreadily for exact deposition of deep local anesthesiato the level of the foreign body. Local anesthesia isadministered best in two stages at the tip of the for-eign body. First, deep local anesthesia is adminis-tered with sonographic guidance in the pathwayof forceps dissection and foreign body removal. Im-mediately before skin incision and forceps dissec-tion, a second bolus of lidocaine is administeredat the tip of the foreign body. This bolus serves todissect the surrounding soft tissues away from theforeign body, facilitating forceps contact, grasping,and removal of the foreign body. The author refersto this bolus dissection as ‘‘hydrodissection’’ of thesoft tissues and finds this technique very helpfulin the forceps removal procedure.

Forceps dissection and removal procedure

After 15 years of experience, sonography is, for sev-eral reasons, the author’s preferred imaging modal-ity for foreign body removal. Sonography isportable, emits no ionizing radiation, and can guidethe removal of radiopaque and non-radiopaque

foreign bodies. Sonography provides excellentthree-dimensional visualization of foreign bodiesand removal instruments. In truth, foreign body re-moval under sonographic guidance is a four-dimen-sional process, with the fourth dimension beingtime. Four-dimensional guidance with sonographyis important: foreign bodies can move during re-moval procedures, some migrating significant dis-tances if not grasped initially or deflecting ifcompletely surrounded by a pus or fluid collection.The author has found that foreign bodies can be re-moved faster, less painfully, more safely, and usuallyaccomplished with smaller incisions (average inci-sion, 4–5 mm) with sonographic guidance thanwith fluoroscopy.

General technical considerations

Interrogation of adjacent soft tissues is essential forthe preprocedural decision-making and planningprocess. Foreign bodies located adjacent and deepto nervous or vascular structures may not be acces-sible for USFBR and may require open surgical re-moval. Foreign bodies in tendons or tendonsheaths require coordination with respective sur-geons and close follow-up. When a retained foreignbody has associated infectious tenosynovitis, closecoordination with the respective surgeon is manda-tory, because some surgeons will mandate open for-eign body removal and wound debridement(Fig. 6). Intra-articular foreign bodies also necessi-tate close consultation with an orthopedic surgeon,especially in the event of a failed attempt at USFBR.Identification of an intra-articular foreign body thatis embedded either in the articular cartilage or un-ossified boney cartilage is important for proceduralplanning. Metallic foreign bodies near vital struc-tures are removed more safely with sonographicguidance than with fluoroscopy, which does notprovide three-dimensional visualization of criticaladjacent structures during the removal process.

Consideration of the technical aspects of USFBRis critical as a radiologist or other physician trainsand develops proficiency in this difficult procedure.Fifteen years of clinical experience and experiencein mentoring the training of more than 2000 physi-cians has revealed that hand position and coordina-tion are of utmost importance. Fine motor controlis required to remove a foreign body with a diameterof 0.5 mm in an ultrasound beam that is 2 mmwide. Fine motor control during USFBR is accom-plished best with the transducer manipulated bythe operator’s nondominant hand and the forcepscontrolled by the dominant hand. Critical to suc-cessful USFBR is proper hand position and graspof the transducer. The optimal hand grasp andtransducer movement have been described as

Fig. 6. Pencil lead and pencil tip wood fragments embedded in the fourth flexor tendon sheath with tenosyn-ovitis in the hand of a 17-year-old boy. Tenosynovitis mandated open removal of the fragments with debride-ment of the gangrenous wound and exploration of the tendon sheath. (A) Transverse sonogram of the handdemonstrating the dense graphite pencil lead and adjacent pencil wood casing (arrow). (B) Transverse sonogramof the hand clearly defines the fourth and fifth flexor tendons with hyperemic flow in the infected fourth flexortendon (curved arrow). The graphite tip (arrow) with dense posterior shadowing (star) is seen penetrating thefourth flexor tendon sheath.


‘‘contact scanning’’ (personal communication, B.D.Coley, MD, 2006). In this coordinated approach,the transducer is grasped at the base with three orfour fingers, with the last finger(s) lying flat onthe patient’s skin and maintaining ‘‘contact’’ withthe patient during transducer movements. Contactscanning serves multiple purposes: reducing fore-arm and hand fatigue, maintaining proper pressureand eliminating pain caused by excessive transducerforce, improving hand–eye–transducer coordina-tion, and facilitating fine motor control and stabil-ity during USFBR procedures.

USFBR is performed with freehand sonography.Needle guides are not feasible in USFBR becauseof the instrumentation required for the procedureand the need for lateral movements during USFBR.The most successful forcep approaches are perpen-dicular or shallowly oblique to the sound beam.USFBR is performed with the highest possible trans-ducers (7–17 MHz); linear-array transducers pro-vide the best field and insonation match withstraight forceps. In operating fields with a small sur-face area (eg, the heel, hand, or toes), small-foot-print compact linear-array (hockey-stick)transducers are ideal. The small hockey-stick trans-ducer is the preferred transducer for most USFBRprocedures because the size and configuration ofthis transducer facilitates fine motor control and re-duces hand fatigue.

Like transducer selection, forceps selection is im-portant for optimal technical success. The authorand colleagues have found that the standard Kelly

forceps provides the best forceps working surfacearea and design for USFBR; the straight Kelly for-ceps is preferred over curved forceps. Instrumentsmust be maintained in a very small straight planeof visualization, and a curved forceps introducesan unnecessary variable. Small Hartman ‘‘alligator’’forceps are useful in deep fields of operation be-cause with a Hartman forceps, unlike a Kelly for-ceps, the articulation of the forceps can occurdeep in a wound. Hartman forceps also haveproven useful in the removal of especially smalland fragile foreign bodies, such small glass frag-ments, because the Hartman forceps facilitates gen-tle grasp and removal, reducing the chance that theforeign body will fragment during removal. Com-mon instruments in commercially assembled pro-cedural kits such as laceration kits include forcepswith serrated teeth and needle drivers with smoothteeth. For smooth metal foreign bodies such asround BB gun pellets, serrated forceps are preferredbecause of the friction they provide during grasp;smooth needle drivers fail to grasp BB pellets se-curely during removal.

USFBR is performed with sterile technique, in-cluding the use of sterile transducer covers. As dis-cussed in the previous section, generous, deepadministration of lidocaine is essential for success-ful USFBR in patients not receiving general anesthe-sia. Furthermore, hydrodissection greatly facilitatesforeign body contact and removal, minimizingcrushing and tearing injury of the surroundingsoft tissues. Once the path of removal is selected,

Shiels676

the foreign body is aligned in the long axis of thesound beam and is positioned eccentrically in thesonographic field, to the side opposite the forcepsentry for deep foreign bodies. The eccentric posi-tion makes up to 50% of the sonographic fieldavailable for visualization of the forceps duringthe blunt dissection and removal processes (Figs.7 and 8). With superficial foreign bodies, the tipof the foreign body is placed at the edge of the trans-ducer closest to forceps entry. Under real-time sono-graphic guidance, the forceps is introduced with thetips closed to dissect bluntly in the plane of the

Fig. 7. Ultrasound-guided foreign body removal of metament of the calf of a 12-year-old boy, using the vertical forbody in the muscle (arrow). (B) Local anesthesia needle (cubody (straight arrow). Note the eccentric positioning of thorientation (arrowheads) grasping the foreign body (arrothe site of foreign body removal, evaluating for residual

foreign body until the tip of the foreign body is con-tacted. The tips of the forceps must remain closeduntil immediately adjacent to the foreign body toavoid unnecessary grasping and crushing soft tis-sues in the dissection field. If hydrodissectionand/or blunt dissection define granulation or fi-brous tissue encasing a longstanding foreign body,sharp dissection may be required to free the foreignbody for successful removal (Fig. 9). In this in-stance, options for sharp dissection include a #11scalpel blade or a large-bore needle (10–18 gauge);sharp dissection of the granulation or fibrous tissue

llic axe fragment embedded in the anterior compart-ceps orientation. (A) Identification of metallic foreignrved arrow) approaching the tip of the metal foreign

e metal foreign body. (C) The forceps tip in the verticalw) during removal. (D) Sonographic interrogation offoreign body fragments. None were present.

Fig. 8. Horizontal orientation of forceps for USFBR of metal needle. (A) Longitudinal sonogram of metal needlevisualizing the full shaft and both ends of the needle. (B) Transducer moved for eccentric needle position inpreparation for removal with the needle tip (straight arrow) in the center of the field of operation. (C) Forceps(curved arrow) in horizontal orientation contacting and deflecting the top of the needle (straight arrow) imme-diately before forceps is opened for grasp and removal.


is performed under real-time sonographic guid-ance. All dissection, blunt or sharp, always is per-formed with clear visualization and avoidance ofadjacent structures such as nerves, vessels, andtendons.

Tactile aspects of the procedure are critical com-ponents in the final stages of the USFBR procedure.Before the forceps tips are opened, the edge of theforeign body is contacted, and the sensation ofthe foreign body is felt in the operator’s fingertips.Metallic, stone, and glass foreign bodies have a crispsensation, and contact as the forceps grasp some-times is audible. Wood and plastic have a more sub-tle, soft feel when grasped. Feeling the resistance ofthe foreign body in the teeth of the forceps is a crit-ical part of the removal process. Additionally, if ad-jacent tissue is grasped instead of the foreign body,detecting the resistance from the tissue during theattempted removal process is critical to avoid tissuedamage.

USFBR is accomplished most quickly with thelong axis of the sound beam aligned with the longaxis of the forceps and foreign body (see Figs. 7

and 8). While longitudinal alignment of the soundbeam, foreign body, and forceps is maintained, theforceps is moved gently, contacting and defining thetop and lateral margins of the foreign body withtactile confirmation. Tactile confirmation is criticalat this point in the USFBR procedure. Volume-aver-age (beam-width) artifacts can create a false appear-ance of contact with the foreign body, when in factthe computed sound beam is summating two adja-cent objects that are not in direct contact. As an al-ternative to defining the top of the foreign body,definition of the bottom (deep) side of the foreignbody occasionally may prove useful (Fig. 10). Oncethe top and both lateral edges are defined, the for-ceps is moved directly above (or below) the foreignbody, the forceps tips are opened slightly, and theforeign body is grasped gently and removed. Twooptions exist in orienting the forceps teeth forgrasping the foreign body: vertical orientation (seeFig. 7;) and horizontal orientation (see Fig. 8). Inthe horizontal orientation, the closed forceps con-tacts the top of the foreign body and, with teethgently opened, is lowered into position for grasp

Fig. 9. Hypoechoic granulation tissue with color Doppler flow documenting vascularity in the solid granulationtissue necessitating sharp dissection for removal of an embedded wood foreign body in the thigh of a 13-year-old girl. (A) Panoramic sonogram of the long wooden foreign body (marked by cursors) surrounded by hypoe-choic granulation tissue. (B) Focused sonogram of the thickest area of granulation tissue (curved arrow)surrounding the tip of the wood foreign body (arrow). (C) Focused sonogram with color Doppler demonstratingvascular in-growth of the solid granulation tissue. The solid granulation tissue necessitated sharp dissection forremoval of this heavily embedded wooden fragment. (D) Photograph of three excellent ultrasound-guidedsharp dissection instruments for foreign body removal (#11 scalpel blade, 10-gauge needle, and 18-gaugeneedle).

Shiels678

and removal. In the vertical orientation, the closedforceps is placed in front of the foreign body tip,teeth are opened vertically, and the foreign bodyis grasped and removed. Grasp of the foreignbody is confirmed tactilely (feeling the incompleteclosure of the forceps tips as they grasp the solid for-eign body) before removal.

If difficulty is encountered with removal attemptsin the longitudinal plane, the transducer may be ro-tated into a transverse plane for removal. In thetransverse sectional plane, the forceps tips can beobserved in the closed position on top of the for-eign body, opening and placed adjacent to the for-eign body, and during the final grasp of the foreignbody before removal. Once the object is grasped,real-time sonography is used to monitor foreignbody removal (especially with wood and glass) toavoid fragmentation during removal. Following re-moval, the soft tissue field previously containingthe foreign body is interrogated sonographicallyto evaluate complete removal versus retention ofsmall fragments (see Fig. 10).

Wound care after removal follows the traditionaltenets of wound closure and management. The au-thor and colleagues perform USFBR with very small(4- to 5-mm) incisions. Because of the small size of

these incisions, sutures have never been requiredfor wound closure. If USFBR is performed in theacute injury phase, small incisions are closed withsterile adhesive strips; if USFBR is performed fol-lowing surgical exploration, previously suturedwounds are resutured if the wound must be openedfor USFBR. If USFBR is performed in the setting ofan established wound infection or abscess, thewound is irrigated with copious amounts of salinelavage, dressed with a sterile dressing, and allowedto heal by secondary intention. Wound follow-upis performed in the radiology clinic or by the pa-tient’s primary physician. Oral antibiotics are ad-ministered routinely to treat puncture-woundinfections established before USFBR.

Pitfalls

USFBR is the most technically challenging ultra-sound-guided interventional procedure to performreliably and successfully. Therefore, laboratorytraining is extremely valuable before attemptingthis procedure on patients. As previously reported,excellent tissue models (turkey breast or beeftongue) are available for preclinical proficiencytraining [6]. These models provide excellent

Fig. 10. Wooden foreign body in the foot surrounded by pus, with successful USFBR. (A) Wood fragment (arrow)with purulent hypoechoic halo (curved arrow). (B) Wood fragment (straight arrow) displaced easily by forceps(curved arrow) in the abscess liquid. (C) Distal tip of the fragment (arrow) observed with real-time sonography dur-ing removal from the abscess cavity (curved arrows). (D) Operative bed interrogated for retained fragments in theabscess (curved arrow). Following interrogation, the abscess is lavaged with saline under sonographic guidance.


simulation of the tissue resistance, the steps re-quired for successful USFBR, and prospective dem-onstrations of pitfalls that can be anticipated andmanaged in clinical situations. In preparing thetraining simulators, it is essential to embed the for-eign bodies with the simulator submerged underwater to avoid introducing air during preparation.Wood, metal, glass, and stone fragments are embed-ded easily for training in USFBR.

Lack of preplanning of logistical elements ofUSFBR procedures can be quite problematic, espe-cially if the radiologist arrives in the operatingroom and the patient is positioned and anesthe-tized in a position disadvantageous to the radiolo-gist. Before the USFBR procedure, the operatingradiologist should plan the room set-up: the loca-tion and exact positioning of the patient on the ta-ble (prone, supine, head to left or right of theradiologist) and the location of the ultrasoundunit. If working in the operating room, the radiolo-gist should specify the position of the table in theroom (operating room tables are mobile), the loca-tion of the anesthesia machine and anesthesiolo-gist, and the position (sitting or standing) of the

radiologist. Failure to attend to any of these detailscan contribute significantly to unnecessary proce-dural difficulties and/or failure.

Intraoperative pitfalls include volume-averagingartifacts, suboptimal forceps positioning or graspposition, and overly aggressive grasping techniques.As discussed previously, volume-averaging artifactscan be extremely misleading if not coupled withtactile feedback. With volume averaging, forcepstips that are both to one side of the foreign bodycan be summated by the computed sonographyunit to appear in good position for removal; onopening the tips, however, the operator is not grasp-ing the foreign body. This pitfall is managed bestwith careful tactile definition of the top and bothsides of the foreign body before returning to thetop of the foreign body for attempted removal. Ifvolume-averaging artifact is a significant operatordifficulty, transverse-plane scanning is an alterna-tive plane for removal.

Forceps hand position can be a potential pitfall,reducing the ergonomic advantage at the time of re-moval. Specifically, the tips of the forceps are con-trolled most readily with hand–transducer–eye

Shiels680

triangulation, if aligned in the horizontal planewith respect to the ultrasound transducer face. Ori-entation of the forceps tips in the vertical plane (inline with the long axis of the sound beam) is analternative plane of operation that may be selectedas an operator preference. The second pitfall, spe-cific to the forceps tips, is blunt dissection and ap-proaching the foreign body with open forceps tipsbefore contact with the foreign body. This maneu-ver will result in unnecessary tissue capture andinjury in the forceps tips and also will impedeboth grasp and removal of the foreign body. Thethird forceps pitfall is referred to as ‘‘central grasp.’’Central grasp occurs when the foreign body isgrasped in the center, away from the tip. Such re-moval efforts result in the fracture of metallic, glass,and wood foreign bodies during the initial removalmaneuver. Central grasping of foreign bodies canquickly convert a single foreign body removal pro-cedure into a multiple foreign body procedure.Similarly, the fourth forceps pitfall, ‘‘aggressivegrasp,’’ can multiply the number of foreign bodiesfor removal or lack thereof. During the grasp andremoval stages of USFBR, gentle and meticulouslycontrolled finger pressure must be maintained toavoid the excessive grasp force that can fracturethe foreign body, possibly into multiple fragmentstoo small to remove. The last forceps pitfall occurswhen foreign bodies are encountered near joints.Blunt dissection is pursued, only to find that thetip of the foreign body cannot be contacted orgrasped because of intra-articular positioning. Inthis instance, the joint capsule is found to be inter-posed between the foreign body and the forceps.The author has completed intra-articular foreignbody removal successfully in this situation, enter-ing the joint by ultrasound-guided arthrotomyusing a #11 scalpel (well visualized withsonography).

Outcomes

In the author’s experience with more than 400 pa-tients, foreign bodies in soft tissue have been de-tected and localized sonographically, with greaterthan 99% success, in a wide variety of anatomic lo-cations, including the trunk, chest wall, hands, feet,arms, legs, neck, face, and orbit (W.E. Shiels II, un-published series data, 2007). Ultrasound detectionand localization is successful in tendons, withinjoint spaces, and even within articular cartilageand unossified boney structures. When attemptedby the radiologist, sonographic characterization isaccurate for more than 94% of foreign bodies(100% accuracy for metal objects, 94% for wood,and 92% for glass). Color Doppler sonography isan excellent tool for discriminating granulation

tissue from purulent collections that form hypoe-choic halos around foreign bodies. Hypoechoic in-flammatory halos (granulation or pus) were seenmost often with wood, with a frequency threefoldgreater than with glass or metal. When linear for-eign bodies (usually metal or glass) lie perpendicu-lar to the skin surface, clear definition of the fulllength of the foreign body can be difficult and canbe aided significantly with angulation of the soundbeam, often with the aid of an acoustic standoffpad.

In the author’s practice with four interventionalradiologists, USFBR is successful in 97% of attempts(W.E. Shiels II, unpublished series data, 2007). For-eign bodies are removed successfully from soft tis-sue with percutaneous USFBR in a wide variety ofanatomic locations including the trunk, chestwall, hands, feet, arms, legs, neck, face, and orbit.USFBR is successful in joint-related locations suchas intratendinous, intracapsular, and intracartilagi-nous structures. Wood, glass, and metal foreignbodies comprise 94% of the foreign bodies re-moved (with pathologic correlation). Fragmenta-tion of foreign bodies occurred in 4% of casesduring removal of metal, glass, wood, and thin-leaf vegetable matter. Fragmentation does notnecessarily result in failure (removal after fragmen-tation was successful in 80% of cases) but mayincrease the time needed to complete foreignbody removal. With respect to practitioner exper-tise, the fine motor and sonographic triangulationskills that are required for USFBR quickly selectout a group of competent physicians who are ableto provide this service. In the author’s experience,simulator training quickly defines a physician’sskills, interest, and potential for procedural compe-tency in USFBR.

In the author’s experience, patient satisfaction isextremely high when USFBR (with competent phy-sicians) is offered as an alternative to either pro-longed and painful attempts at blind removal inan emergency department or to open foreignbody removal with generous incisions. In the au-thor’s institution, access to emergency departmentservices is a critical patient care issue. If a patientpresents to the emergency department with a sus-pected or documented soft tissue foreign body,the emergency department physician briefly at-tempts traditional forceps removal. If blind re-moval is unsuccessful (or not warranted becauseof a radiographically documented deep foreignbody), the patient is referred to the interventionalradiology service for outpatient removal of the for-eign body by one of four interventional radiolo-gists proficient in USFBR. In the NationwideChildren’s Hospital institution, this foreign bodymanagement protocol provides rapid emergency


department disposition and excellent care of pa-tients who require image-guided removal of a for-eign body. Rapid disposition and referral toa center of predictable clinical excellence allowsgreater patient access and appropriate use of valu-able and often overstretched emergency depart-ment services.

Summary

Soft tissue foreign bodies are a common clinical di-lemma in both pediatric and adult patients. Sonog-raphy provides timely detection, localization, andcharacterization of foreign bodies in soft tissue.USFBR is a safe and highly successful minimallyinvasive procedure that aids significantly in the ex-peditious treatment of and avoidance of complica-tions in patients who have soft tissue foreignbodies. Focused laboratory training is critical tothe successful implementation of a sonographicforeign body management practice.

References

[1] Shiels WE II, Babcock DS, Wilson JL, et al. Local-ization and guided removal of soft-tissue foreignbodies with sonography. AJR Am J Roentgenol1990;155:1277–81.

[2] Shiels WE II. Soft-tissue foreign bodies: diagnosticand therapeutic radiological management. Emer-gency radiology in childhood (postgraduatecourse), European Society of Pediatric Radiology.Berlin (Germany): Springer-Verlag; 1998. p. 46–55.

[3] Gooding G, Hardiman T, Summers M, et al. So-nography of the hand and foot in foreign bodydetection. J Ultrasound Med 1987;6:441–7.

[4] Fornage BD, Schernberg FL. Sonographic diagno-sis of foreign bodies of the distal extremities. AJRAm J Roentgenol 1986;147:567–9.

[5] Jacobson JA, Powell A, Craig JG, et al. Woodenforeign bodies in soft tissue: detection at US. Radi-ology 1998;206:45–8.

[6] Georgian-Smith D, Lyon RD, Schwartzberg BS, et al.A smorgasbord of interventional phantoms. Semi-nars in Interventional Radiology 1997;4(4):377–87.



683

Sonographic Evaluation of theMusculoskeletal Soft Tissue MassesRonald S. Adler, PhD, MDa,b,*, Sinchun Hwang, MDc

- Learning objectives- Nonneoplastic masses- Benign cysts

Synovial cystsGanglion cystsMeniscal and paralabral cystsEpidermoid cysts (sebaceous cysts)

- Posttraumatic masses- Reactive/inflammatory masses- Neoplastic masses- Benign neoplastic masses

LipomasSuperficial fibromatosesExtra-abdominal desmoid tumorsMyxomaNerve sheath tumorsVascular malformations

- Malignant neoplasms- Lesions of bone- Summary- References

Learning objectives confirm the presence or absence of a mass with

After reading this article, the reader should be ableto:

� Describe sonographic features of benign andmalignant soft tissue masses.

� Distinguish solid from cystic soft tissuemasses.

� List the current indications of sonography inscreening and diagnosis of a variety of tumorand tumor-like soft tissue masses.

� Know a therapeutic role that can further aidin treatment and surveillance of soft tissuemasses.

When a patient presents with localized swelling,sonography can be used as a screening tool to

a Weill Medical College of Cornell University, 535 East 7b Division of Ultrasound and Body Imaging, Hospital for10021, USAc Department of Radiology, Memorial Sloan Kettering10022, USA* Corresponding author. Division of Ultrasound and Bod70th Street, New York, NY 10021.E-mail address: [email protected] (R.S. Adler).


high negative predictive value and to localize themass [1]. Sonography is an excellent imagingmodality to determine the cystic or solid nature ofa mass and its anatomic relation to adjoining struc-tures. Masses can be characterized in terms of thesize, number, and vascularity in addition to thepresence of calcification or ossification. In thismanner, a large variety of benign soft tissue masses,such as ganglion cysts, bursae, lipomas, and inflam-matory masses, may be accurately diagnosed, oftenobviating the need for further imaging. In certaininstances, a specific diagnosis can be made.

Sonography provides an accurate means toobtain guided biopsies or aspirations with minimalpatient discomfort [2,3]. Because ultrasound-guided biopsy is performed in real-time, it

0th Street, New York, NY 10021, USASpecial Surgery, 535 East 70th Street, New York, NY

Cancer Center, 1275 York Avenue, New York, NY

y Imaging, The Hospital for Special Surgery, 535 East




Box 1: Indications for sonography in imagingof soft tissue masses

� Screen for or confirm the presence of a sus-pected mass.� Determine the cystic or solid nature of a mass

and as its anatomic relation to adjoiningstructures.� Characterize a soft tissue mass in terms of

size, number of lesions, and vascularity.� Aid in biopsy of a mass or aspiration of fluid

to provide a tissue diagnosis safely.� Assist in treating soft tissue masses, for

example, the therapeutic injection of a Mor-ton’s neuroma, ganglion cyst, or symptom-atic bursa with steroid and local anesthetic.� Evaluate for local recurrence in tumor imag-

ing and monitor therapeutic response afterexcision, chemotherapy, or localizedradiation.

Adler & Hwang684

minimizes the risks for local tissue injury whileclosely monitoring patients during procedures.Neurovascular structures can be avoided, anda mass may be optimally biopsied based on theobserved solid or vascular components that

Fig. 1. Baker’s cyst. (A) Transverse image of a complex Bak(B) Echogenic needle (N) has been positioned within thecyst aspiration. (C) Cyst is almost completely collapsed ab

correlate with the degree of malignant behavior. So-nography therefore can provide an important ad-junctive tool in the workup of a suspectedmalignant soft tissue tumor. In tumor imaging, so-nographic assessment is performed for local recur-rence and to monitor therapeutic response afterexcision, chemotherapy, or localized radiation.

Ultrasound also plays an important therapeuticrole in the treatment of soft tissue masses, such astherapeutic injection of Morton’s neuromas andsymptomatic bursa with steroid and local anes-thetics [2,4].

The purpose of this article is to describe sono-graphic findings of a variety of different soft tissuemasses. The authors review the role of sonographyin evaluating soft tissue masses in their practice,which is part of an orthopedic and rheumatologicsubspecialty hospital (Box 1).

Nonneoplastic masses

Common nonneoplastic masses include benigncysts and posttraumatic, reactive, and inflammatorylesions. These include synovial cysts, ganglion cysts,tenosynovitis, sebaceous cysts, and masses that un-dergo cystic changes (eg, abscess, necrosis,

er’s cyst that contains wall thickening and septations.cyst beyond the central septation, thereby permittingout the indwelling needle.

Fig. 2. Volar wrist ganglion cyst. (A) Longitudinal ultrasound image of a bilobed ganglion cyst at the radial volaraspect of the wrist. A thin neck (labeled) is demonstrated extending to the volar joint capsule. (B) Power Dopplerimage shows the close relation of the cyst to the adjacent radial artery. (C) On this transverse image, a 22-gaugeneedle (arrow) was positioned through the flexor carpi radialis tendon (FCR) into the cyst (Pre), deep to the ra-dial artery (RA). (D) Cyst has been aspirated (Post) with decompression about the needle tip. Monitoring thisprocedure in real-time enables one to maintain a fixed needle position during aspiration while avoiding the ra-dial artery.

Musculoskeletal Sonography 685

hematoma). An inflammatory phlegmon may pres-ent as a discrete mass; likewise, muscle rupture withhematoma formation or secondary hypertrophymay present as mass-like lesions. Reactive

Fig. 3. Meniscal cyst. (A) Coronal ultrasound image of th(thin arrow) contiguous with a complex cyst (thick arrowtendon, and lateral meniscus. Ultrasound is helpful in delimultiloculated, containing thick tenacious fluid, septatio(LFC) and tibia (TIB) are labeled. (B) Needle has been pothe purpose of aspiration and injection with a therapeutunder direct visualization.

pseudotumors, such as Morton’s neuromas, andpostamputation neuromas may present as painfulmasses; swelling attributable to a long-standingforeign body reaction may present as a localized

e lateral knee joint shows a horizontal meniscal tear) situated between the iliotibial band (ITB), popliteusneating the complex nature of the cyst, which may bens, and meniscal debris. The lateral femoral condylesitioned within a cystic component of the mass for

ic mixture. The cyst may be mechanically fenestrated

Fig. 4. Epidermoid cyst. A heterogeneous nodule ispresent in the subcutaneous fat of the back in this pa-tient, abutting and mildly distorting the overlyingdermis (D) and displaying a characteristic lamellatedappearance.

Adler & Hwang686

mass. Therefore, the clinical scenario under whichthese soft tissue masses present should be takeninto account in the differential diagnosis.

Benign cysts

Sonography has traditionally been the method ofchoice in diagnosing cystic masses [5]. The cysticmasses commonly present as localized swellingssituated about joints, often corresponding to syno-vial-lined structures, ganglion, and paralabral ormeniscal cysts. A diagnosis is often suspectedclinically in view of the characteristic location ofthese lesions.

Synovial cysts

Synovial cysts are often recognized by location andcommunication with a joint. The most commonsynovial cyst is a popliteal or Baker’s cyst, whichcorresponds to a distended medial gastrocnemius-semimembranosus bursa. Communication betweena popliteal cyst and the posterior knee between themedial gastrocnemius and semimembranosustendons is an important finding to exclude other

Fig. 5. Muscle rupture. (A) Longitudinal sonogram over thheimer’s disease who had fallen and developed swellingbrachialis muscle with numerous intrasubstance tears apthe development of focal myositis ossificans (MO). (B)(BR) containing central cystic spaces and compressing the

cystic masses. A popliteal cyst may contain variableamounts of fluid and nodular debris, often reflectiveof underlying joint pathologic findings. Osteochon-dral bodies may be present within a synovial cyst.Patients may complain of painful swelling andrestricted flexion. After rupture, a popliteal cyst canresult in diffuse pain and swelling in the calf. Thenext most common location of a synovial cyst is inthe hip, corresponding to an iliopsoas bursa, whichis frequently seen in the setting of underlying rheu-matoid arthritis. Patients presenting with palpablemasses in the shoulder over the acromioclavicularjoint may likewise present with a synovial cyst thatcommunicates with the glenohumeral joint bymeans of the acromioclavicular joint. Synovial cystsare often amenable to ultrasound-guided aspirationand injection (Fig. 1) [2].

Ganglion cysts

Ganglion cysts can occur anywhere, although theymost commonly appear in the hand, wrist, foot,and ankle. Cysts involving the dorsal scapholunateligament, volar radiocarpal joint capsule, and volarretinaculum of the metacarpophalangeal joints aremost common in the hand and wrist, whereasdorsal midtarsal cysts are most common in theankle and foot. These cysts characteristicallycontain clear gelatinous material and may be hardto palpation. They may cause symptoms secondaryto mechanical impingement of adjacent structures.Ganglion cysts are usually anechoic on sonographyand may contain multiple locules. They can bereadily aspirated and injected with local anestheticand steroid under sonographic guidance (Fig. 2).Ultrasound guidance enables placement of theneedle to avoid the surrounding neurovascularstructures and to verify the intracystic location.A characteristic contrast effect often presents wheninjecting the cyst with a steroid-anesthetic mixture[5].

e brachialis muscle of an 80-year-old woman with Alz-over her arm. Ultrasound demonstrates an enlargedpearing as discrete hypoechoic areas, swelling, and

Transverse sonogram shows the expanded brachialisoverlying biceps muscle (BM). H, humerus.

Fig. 6. Myofascial tear of the medial head of the gas-trocnemius muscle (tennis leg) resulted in the devel-opment of a large hematoma 1 week after injury.The sonographic appearance of the hematoma is pre-dominantly hypoechoic to completely anechoic inplaces, which, in this case, dissects between the me-dial gastrocnemius (MHG) and soleus muscle (S).


Meniscal and paralabral cysts

Meniscal and paralabral cysts usually occur ina para-articular location, and they are associatedwith meniscal or labral tears [1,6]. They commonlyoccur in the knee, shoulder, and hip (Fig. 3). Be-cause of the paucity of tissue about the knee, theytypically present as an area of swelling. In the hipand shoulder, they rarely present as a palpable mass.

Epidermoid cysts (sebaceous cysts)

Epidermoid cysts are the clinically most commonepithelial-lined cysts arising in the hair-bearing

Fig. 7. Stump neuromas. A patient with history of below-talong the stump. Two exquisitely tender nodules (arrows)symptoms, with the more superficial nodule (lower right)sis on. The more typical appearance of posttraumatic or pnodule (upper left), although, as indicated in this examp

dermal or subdermal areas of the body [7]. Theyare filled with keratin, occasionally containingcalcifications. On sonography, epidermoid cystsare most often hypoechoic with variable echogenicfoci presumably representing lamellated keratin. Alamellar sonographic pattern has been describedin these lesions, reflecting their composition(Fig. 4). They are filled with keratin, occasionallycontaining calcifications. When they are ruptured,epidermal inclusion cysts may show color Dopplersignal mimicking solid masses [8].

Posttraumatic masses

Posttraumatic changes can appear clinically asa mass, such as a hematoma, retracted rupturedmuscle or tendon complex, myositis ossificans,muscle necrosis, or focal myositis.

Rupture of muscles with retraction of myotendi-nous complexes often presents as a palpable mass,and the diagnosis can be often made on the basisof clinical history and physical findings. On sonog-raphy, muscles with partial ruptures can appear asa discrete mass because of partial retraction, hema-toma, edema, or, in more chronic cases, secondarymuscle hypertrophy (Fig. 5). Sonography has theadvantage of observing the degree of muscle

he-knee amputation developed pain in two locationswere evident sonographically. Both produced similar

being somewhat more symptomatic with the prosthe-ostsurgical neuromas is that of a discrete hypoechoic

le, their appearances are somewhat variable.

Fig. 8. Third web space Morton’s neuroma. Colorizedgray-scale image in the long axis shows a discreteelliptic predominantly hypoechoic nodule (arrow) inthe third web space of the right foot, which was in-compressible with palpation. The normal interdigitalfat (F) should be echogenic. Use of a colorized grayscale can sometimes be helpful in increasing theconspicuity of these lesions.

Adler & Hwang688

retraction and the extent of the muscle tear dynam-ically. This helps to evaluate these pseudotumors,which may only be apparent clinically in thecontracted state, and also enables detection of a fas-cial herniation, seroma, or hematoma occasionallyassociated with ruptured muscles.

Hematomas vary in appearance depending ontheir age (Fig. 6). An acute or subacute hematomacan be hyperechoic relative to surrounding muscles,whereas old liquefied hematomas can becomeprogressively hypoechoic, more complex, or evenanechoic [1]. In the authors’ experience, echogenic-ity does not correlate with the degree ofliquefaction.

Myositis ossificans can develop as a complicationof trauma or surgery. The calcifications are hypere-choic and peripheral with posterior acoustic shad-owing. Radiographs are helpful in confirming thepresence of peripheral calcification in myositisossificans, although early calcification may beapparent sonographically before it is evident onradiographs.

Reactive/inflammatory masses

Inflammatory masses can be noninfectious or infec-tious in origin. Noninfectious reactive and inflam-matory masses include neuromas, giant celltumors of the tendon sheath (GCTTSs), foreignbody granulomas, and rheumatoid nodules. Infec-tious inflammatory masses include abscesses,phlegma, pyomyositis, and cellulitis.

Neuromas can occur at amputation sites (stumpneuromas) or in the interdigital web spaces (Mor-ton’s neuromas), or they may occur after surgery.Postamputation stump neuromas are randomly ori-ented axonal overgrowths producing a mass sur-rounded by organized layers containing Schwanncells and fibroblasts [4]. On sonography, they areseen as ovoid hypoechoic nodules continuouswith the transected nerve (Fig. 7). Morton’s neuro-mas are pseudotumors that form around the inter-digital nerves. They are most common in the thirdand second web spaces of the foot; they rarely occurin the first or fourth web spaces [2]. Morton’s neu-romas are typically hypoechoic with or withoutwell-demarcated margins, and they may have asso-ciated adventitial bursa (Fig. 8). Sonography pro-vides a useful method to guide for intralesionaltherapeutic injection [9].

A GCTTS is the second most common soft tissuemass in the hand after ganglion cysts [10]. A GCTTSis a localized synovial proliferation that outgrowsthe confines of the tendon sheath and tends to oc-cur in the volar aspect of the fingers. Because theGCTTS is the most common mesenchymal neo-plasm of the hand, it is often called ‘‘fingeroma.’’

Other common sites include the feet, ankles, andknees. Histologic features include multinucleatedgiant cells, hemosiderin deposition, and foamymacrophages [11,12]. A GCTTS can be localized ordiffuse. The localized form, also known as nodulartenosynovitis, is more common than the diffuseform [10]. On sonography, they appear as hypoe-choic masses in close relation to tendons (Fig. 9).They are frequently hypervascular on color flowimaging.

Foreign body granulomas present as a hard pain-ful lump with or without a history of penetratingtrauma. Sonography is superior to radiographs indetecting radiolucent foreign bodies, such aswood [1]. Foreign bodies are usually hyperechoicand may have a surrounding hyperemic hypoechoichalo (Fig. 10). Rheumatoid nodules in the handsare elongated hypoechoic nodules superficial to orwithin the tendons of the extremities. They areknown to occur in 20% of patients who have rheu-matoid arthritis [1].

Abscess and cellulitis often present with similarclinical findings, thus causing a diagnostic dilemmain clinical management. Differentiating an abscessfrom cellulitis can be readily done on sonography.Abscesses are often complex cystic collections withirregular walls, and they may contain septationand internal echoes reflecting debris or pus(Fig. 11). The presence of a surrounding hyperemicring on power Doppler imaging may be helpful indifferentiating these from organizing hematomas.Percutaneous aspiration under ultrasound guidancecan provide a definitive diagnosis. In cellulitis, thereis subcutaneous edema in which the subcutaneous

Fig. 10. Foreign body granuloma. This patient had a history of scraping her elbow on a tree 3 months before herultrasound examination. She developed soft tissue swelling over the olecranon and was sent for possible aspi-ration of olecranon bursitis. Longitudinal (A) and transverse (B) images obtained over the posterior olecranonshow a linear echogenic structure with some posterior acoustic shadowing (arrow). There is a surrounding softtissue mass (M), resulting from a foreign body reaction from an indwelling wooden splinter.

Fig. 9. GCTTTS. Longitudinal (A) and transverse (B) images of an eccentric multilobular hypoechoic nodule(arrows) are seen in close relation to the flexor tendon of the fifth digit at the distal interphalangeal joint.The close relation of the nodule to the tendon (T) is better appreciated on the transverse image. (C) Coronalfast spin echo proton density image of the fifth digit shows a bilobed intermediate signal intensity nodule (ar-row) corresponding to that seen on ultrasound.


Fig. 11. Inflammatory mass. This patient with a history of previous below-the-knee amputation developed a pain-ful swelling over the stump during a 1-week period. He underwent ultrasonography to assess for a possible ab-scess. (A) Coronal sonogram over the stump shows a heterogeneous mass (arrows) with a hypoechoic cyst-likearea proximally and a homogeneous echogenic portion distally. Aspiration of both components producedbloody material. tib, tibia. (B) Marked hyperemia associated with the mass demonstrated before aspiration sug-gests the inflammatory nature, which had likely undergone hemorrhage because of persistent mechanical abra-sion of the friable inflammatory soft tissue by the prosthesis.

Adler & Hwang690

fat appears enlarged and echogenic (Fig. 12). Ser-piginous hypoechoic areas may appear, correspond-ing to lymphatic resorption. Increased vascularityand skin thickening may also occur.

Neoplastic masses

On sonography, soft tissue tumors are evaluated interms of echogenicity, size, vascularity, and numberof lesions in addition to their relation to adjacentstructures. In some instances, a specific diagnosismay be possible. In many cases, however, detailedcharacterization of the tumor and its relation tothe surrounding soft tissues require further imagingevaluation with MR imaging or CT. The primaryrole of ultrasound in many cases is to provide guid-ance for percutaneous biopsy.

Fig. 12. Focal edema producing a mass. The patienthad a history of previous ankle surgery with develop-ment of localized leg swelling and pain. The results ofa Doppler study to exclude deep vein thrombosiswere negative. Localized painful swelling indicatedby the patient corresponds to an area of increasedechogenicity (arrow) within the subcutaneous fat.The fat (F) is asymmetrically enlarged with loss of in-ternal morphology at the affected site, as indicated inthis extended field-of-view image.

Benign neoplastic masses

Lipomas

Lipomas are common benign soft tissue tumors,which can be subcutaneous, intramuscular, or inter-muscular. They are hypovascular, predominantlyhomogeneous, and often hyper- or isoechoic tothe surrounding fat. In the subcutaneous fat, theymay be encapsulated (Fig. 13). The long axis oflipomas is usually parallel to the skin surface. Theechogenicity of subcutaneous lipomas can bevariable, with more than half having a hyperechoicor mixed pattern [13]. Diagnosis of a lipoma onsonography should be made with caution, becausethere are malignant and benign fat-containinglesions, such as low-grade liposarcoma and angioli-poma, that can mimic lipomas. In a retrospective

Fig. 13. Lipoma. The patient had a fluctuant painlesssoft tissue mass over the buttock region. An elon-gated soft tissue mass within the subcutaneous fatand with similar echogenicity and morphology tothe adjacent fat is present. The mass (M) appearswell circumscribed and parallels the adjacent softtissue planes. The gluteal muscles (glut) and greatertrochanter (GT) are labeled.

Fig. 14. Palmar fibromata. Transverse (A) and longitudinal (B) sonograms obtained over the flexor tendons (T) ofthe third finger demonstrate a heterogeneous and predominantly hypoechoic soft tissue nodule (arrows) abut-ting the flexor tendon sheath. The metacarpal phalangeal joint (MCP) of the third digit is labeled. On the trans-verse image (A), the lateral margins of the nodule are delineated by the asterisks.


study of 45 biopsy-proved lipomas, sonographicsensitivity ranged between 40% and 52%, and accu-racy ranged between 49% and 64% [14].

Superficial fibromatoses

These represent benign fibrous proliferations thatare typically small and slow-growing subcutaneouslesions. They can occur as palmar fibromatosis,plantar fibromatosis, juvenile aponeurotic fibroma,and infantile digital fibroma. Palmar fibromatosis(Dupuytren disease) (Fig. 14) is the most commontype of superficial fibromatosis, with a prevalenceof 1% to 2% in the general population, and is bilat-eral in 42% to 60% of cases [15]. Plantar fibroma-tosis (Ledderhose disease) can be bilateral in 20%to 50% of cases. It may coexist with palmar fibro-matosis in 10% to 65% of patients [15]. The nod-ules are seen most commonly in the medialaspect of the plantar aponeurosis [16]. On sonogra-phy, plantar fibromatoses are seen as a single hypo-echoic mass arising within the superficial margin ofthe plantar fascia (Fig. 15) [1]. They can be multi-ple, confluent, and fixed involving the skin or caninvade the deep structures of the foot [15]. Theycan be associated with Peyronie’s disease andknuckle pads.

Fig. 15. Plantar fibroma. Longitudinal extended field-of-view image of the plantar aspect of the foot showsan elongated heterogeneous nodule (arrow) expand-ing the distal plantar fascia, whose axis parallels thefascia. Incidentally noted are enlargement andinhomogeneity of the proximal plantar fascia at thecalcaneal (calc) origin, suggesting coexisting plantarfasciitis.

Extra-abdominal desmoid tumors

Extra-abdominal desmoid tumors are benignmyofibroblastic neoplasms originating from themuscle aponeurosis outside of the abdominalcavity. They constitute a subtype of deep fibromato-ses [15]. Although desmoid tumors lack metastaticpotential, the local recurrence rate is as high as 87%because of their aggressive local infiltration [15].They are more common in young patients, andcommon sites of occurrence include the shoulder,

pelvis, and thigh. On ultrasound, they are infiltra-tive, hard, and heterogeneous masses (Fig. 16).

Myxoma

Soft tissue myxoma is a benign neoplasm arisingfrom fibroblasts that produce an excessive amountof mucopolysaccharide. Soft tissue myxoma hasbeen associated with fibrous dysplasia [12,17].Most myxomas occur in the intramuscular com-partment of the thigh, upper arm, calf, and buttock,and cystic components are common features (83%)[17]. On sonography, myxomas are soft fluctuanthypoechoic masses, which are encapsulated andusually contain cysts (Fig. 17). Differentiation ofmyxoma from low-grade myxoid liposarcomamay be difficult.

Nerve sheath tumors

Benign nerve sheath tumors include schwannomas(neurilemmomas) and neurofibromas. Definite

Fig. 16. Extra-abdominal desmoid. (A) Heterogeneous infiltrative mass within the long head of the biceps muscle(arrows) is evident. The humerus (HUM) is labeled. (B) The results of an ultrasound-guided biopsy (BX) of theheterogeneous area were consistent with a desmoid tumor.

Adler & Hwang692

diagnosis requires direct visualization of the enter-ing and exiting nerves on either side of the lesion(Fig. 18). Normal peripheral nerves demonstratehypoechoic bundles of neural fascicles surroundedby hyperechoic connective tissue on transverse im-ages. Schwannomas tend to be hypoechoic, round,well circumscribed, and eccentric with tapered endswith cyst formation. Neurofibromas are often elon-gated parallel to the long axis of the nerve. Schwan-nomas and neurofibromas can exhibit posterioracoustic enhancement and hyperemia (Fig. 19)[18]. Distinguishing neurofibromas from schwan-nomas can be difficult because they share a similarsonographic appearance.

Fig. 17. Myxoma. A predominantly hypoechoic encap-sulated mass was incidentally discovered in thispatient during evaluation for possible kneereplacement. This extended field-of-view longitudi-nal ultrasound image shows the mass in the plane be-tween the rectus femoris and vastus intermediusmuscles, containing cystic components caudally (ar-row). An ultrasound-guided biopsy showed this tobe consistent with a myxoma.

Vascular malformations

Hemangiomas are common vascular malforma-tions representing up to 7% of all benign soft tissuetumors and affecting women more often than men[19]. They are the most commonly diagnosed softtissue tumors in pediatric patients [19]. Soft tissuehemangiomas can be subtyped in five different his-tologic categories depending on types of vascularchannels. Capillary hemangiomata, which usuallyspontaneously involute, are the most commontype [16]. Cavernous hemangiomata are largerand often intramuscular; these occur later in life,and spontaneous involution does not occur [19].On sonography, they can demonstrate prominent

Fig. 18. Nerve sheath tumor. This patient had a palpa-ble nodule along the dorsal aspect of the ankle andunderwent ultrasonography to evaluate for a possibleganglion cyst. This longitudinal sonogram shows a hy-poechoic solid mass that is well marginated and hastapered ends. The linear structure entering and exit-ing both sides of the lesion (arrows) is the deep pero-neal nerve. The findings are diagnostic for a nervesheath tumor. The eccentricity of the mass relativeto the nerve favors a schwannoma.

Fig. 19. Nerve sheath tumor. (A) Long-axis gray-scale image of a hypoechoic well-marginated soft tissue mass inthe volar aspect of the forearm. (B) The mass demonstrates marked vascularity on power Doppler imaging. Anultrasound-guided biopsy and surgical pathologic examination showed this to be a benign nerve sheath tumor(schwannoma).


vascular channels and phleboliths and may containfat (Fig. 20). Arteriovenous malformations (AVMs)can be distinguished from hemangiomas by highflow on Doppler imaging. They may display arterio-venous shunting. In a study by Paltiel andcolleagues [20], hemangiomas predominantly ap-peared as a solid tissue mass on sonography (48of 49 cases), whereas none of the vascular malfor-mations did (0 of 38 cases), and the mean venouspeak velocity was significantly lower for hemangi-omas than for AVMs.

Malignant neoplasms

Malignant soft tissue tumors include primary ormetastatic neoplasms. The frequency of sarcomasincreases with increasing age. The most commonmalignant sarcomas are rhabdomyosarcoma inthe first 2 decades and malignant fibrous histiocyto-ma in the fifth to seventh decades [21].

Fig. 20. Vascular malformation in the flexor compartmenDoppler (B) images over the volar aspect of the forearm shcontain blood flow on power Doppler imaging. The echogA large cavernous hemangioma was confirmed at surgery

On sonography, malignant soft tissue tumors areusually hypoechoic and often hypervascular. Theymay be well marginated (Fig. 21). They may havecystic components and areas of necrosis, and theymay also have dystrophic calcification (Fig. 22).The vascularity of tumors depends on their degreeof neoangiogenesis, and their vessels are histologi-cally characterized by a lack of the muscular layerand irregular contours [22]. Several investigatorshave suggested that color and power Dopplersonography may aid in distinguishing malignanttumors from benign tumors and that a quantitativerelation may exist with respect to tumor grade[22–24]. Hyperemia is not a constant feature inall malignant tumors, however, nor is it necessarilyabsent in all benign masses (see Fig. 19). The resultsof the Doppler sonographic assessment shouldtherefore be dealt with as part of the imagingworkup to characterize a potentially malignantmass. For example, in certain instances, spectral

t of the forearm. Transverse gray-scale (A) and powerow a heterogeneous mass with large cystic spaces thatenic areas correspond to intralesional fat deposition..

Fig. 21. Low-grade sarcoma. A 35-year-old man developed a slowly growing painless mass along his posterolat-eral thigh. Transverse gray-scale (A) and power Doppler (B) images of the mass show this to be a well-circum-scribed hypoechoic vascular mass in the posterior compartment of the thigh. The femur (F) is labeled. (C)Ultrasound-guided biopsy was performed, showing this to be a low-grade myxoid liposarcoma. An echogenictip of a 12-gauge biopsy gun is evident (arrow) within the central portion of the mass.

Adler & Hwang694

Doppler imaging of malignant soft tissue tumorsusing a resistive index (RI) was considered unsuc-cessful in distinguishing benign from malignanttumors because of the wide range of the RI. Ina study of 53 soft tissue masses by Kaushik andcolleagues [24], the RI for benign masses rangedfrom 0.44 to 1.0, whereas the RI for malignanttumors ranged from 0.28 to 1.0 and there was nostatistically significant difference between benignand malignant masses. Conversely, mean systolicpeak velocity was shown to be higher in malignanttumors. Dock and colleagues [25] analyzed 123patients by using the highest systolic peak flow

velocities and concluded that a flow velocity greaterthan 0.4 m/s may be a reliable parameter to differ-entiate malignant from benign tumors. Althoughspectral analysis may not be always useful, overallvascularity correlates with grade and may providea method to follow response to chemotherapyand radiation therapy.

Sonography plays an important role in biopsy ofa malignant mass (Fig. 23). A study has shown thatsonography-guided percutaneous core needlebiopsy yields highly concordant histopathologicfindings of tumors as compared with surgicalbiopsy [26]. Sonography can be also used as

Fig. 22. High-grade sarcomas. Extended field-of-view images are shown in two different patients with high-grade pleomorphic liposarcomas in the thigh. Both present as large heterogeneous masses with numerous cysticcomponents (cys) in one mass (A) and areas of dystrophic calcification or ossification (arrow) in the other. (B)Both lesions demonstrated marked vascularity on power Doppler imaging.


a tool to follow up therapeutic response and to as-sess for local recurrence with a relatively high accu-racy. In a study of 50 patients by Arya andcolleagues [27], 26 patients had sonographicallypositive recurrence, 24 patients demonstrated histo-pathologically confirmed recurrence, and 13 of the18 sonographically tumor-negative patients weresurgically confirmed as being negative forrecurrence.

Fig. 23. Lymphoma. Longitudinal (A) and transverse (B) grechoic mass in the volar aspect of the forearm. The mass w(C) On power Doppler imaging, the mass is demonstrated tdirected to be intralesional, avoiding the adjacent neurothe biopsy.

Lesions of bone

Although osseous abnormalities presenting as softtissue swelling can usually be sorted out with con-ventional radiography, it should be recognizedthat abnormalities of the bone contour often pres-ent as soft tissue swelling. Simple examples wouldinclude a carpal boss and exostosis. Fracture calluscan likewise present as a painful mass. When

ay-scale images demonstrate a well-marginated hypo-as closely related to the radial artery (RA) and nerve.o be hypervascular. (D) Ultrasound-guided biopsy wasvascular bundle. Lymphoma was diagnosed based on

Fig. 24. Recurrent giant cell tumor. A young woman in the second trimester of pregnancy had soft tissue swellingat the site of a previously excised and packed giant cell tumor of bone. Ultrasound was requested to assess andfollow the lesion during pregnancy. (A) Baseline longitudinal gray-scale image of the distal radius shows a hypo-echoic area in the radial styloid (arrow). (B) On 4-month follow-up, there is cortical thinning with developmentof a fluid-hematocrit level (arrow), suggesting coexistent aneurysmal bone cyst formation.

Adler & Hwang696

osseous lesions expand the cortex or cause patho-logic fractures, they may develop soft tissue compo-nents that often produce soft tissue swelling(Fig. 24).

Summary

Sonography is a useful and noninvasive imagingmodality to evaluate soft tissue masses. It can beused as a first-line screening modality to confirmthe presence of a soft tissue mass and may obviatethe need for further imaging. In the case of benigncystic masses, such as ganglia or bursae, therapeuticinterventions may be performed at the time ofinitial assessment. In the case of malignant tumors,they can be safely biopsied under real-time guid-ance, thereby avoiding neurovascular structures,and changes in size and vascularity of tumors mayprovide further information in assessing clinicalresponse and local tumor recurrence.

References

[1] Fornage BD. Soft tissue masses: the underutiliza-tion of sonography. Semin Musculoskelet Radiol1999;3:115–33.

[2] Adler RS, Sofka CM. Percutaneous ultrasound-guided injections in the musculoskeletal system.Ultrasound Q 2005;19:3–12.

[3] Konermann W, Wuisman P, Ellermann A, et al.Ultrasonographically guided needle biopsy ofbenign and malignant soft tissue and bonetumors. J Ultrasound Med 2000;19:465–71.

[4] Ernberg LA, Adler RS, Lane J. Ultrasound in thedetection and treatment of a painful stumpneuroma. Skeletal Radiol 2003;32:306–9.

[5] Luchs JS, Sofka CM, Adler RS. Contrast effect ofcombined steroid and anesthetic injections: invitro analysis. J Ultrasound Med 2007;2:227–31.

[6] Beggs I. Ultrasound of soft tissue masses. Imag-ing 2002;14:202–8.

[7] Kim SH, Cha ES, Kim HH, et al. Spectrum ofsonographic findings of superficial breastmasses. J Ultrasound Med 2005;24:663–80.

[8] Lee HS, Joo KB, Song HT, et al. Relationshipbetween sonographic and pathologic findingsin epidermoid inclusion cysts. J Clin Ultrasound2001;29:374–83.

[9] Sofka CM, Adler RS, Ciavarra G, et al. Ultra-sound-guided interdigital neuroma injections:short-term clinical outcomes after a single percu-taneous injection—preliminary results. HSSJournal 2007;1:44–9.

[10] Kransforf MJ, Murphey MD, Smith SE. Imagingof soft tissue neoplasms in the adult: benigntumors. Semin Musculoskelet Radiol 1999;3:21–37.

[11] Rosenberg AE. Skeletal system and soft tissuetumors. In: Cotran RS, Kumar V, Robbins SL,et al, editors. Robbins’ pathologic basis ofdisease. 5th edition. Philadelphia: W.B. SaundersCompany; 1994. p. 1260–1.

[12] Enzinger FM, Weiss SW. Soft tissue tumors. 3rdedition. St. Louis (MO): Mosby; 1995. p. 736–42,1045–51.

[13] Fornage BD, Tassin GB. Sonographic appearanceof superficial soft tissue lipomas. J Clin Ultra-sound 1991;19:215–20.

[14] Inampudi P, Jacobson A, Fessell DP, et al. Soft-tissue lipomas: accuracy of sonography indiagnosis with pathologic correlation. Radiology2004;233(3):763–7.

[15] Robbin MR, Murphey MD, Temple HT, et al.Imaging of musculoskeletal fibromatosis. Radio-graphics 2001;21:585–600.

[16] Griffith JF, Wong TY, Wong SM, et al. Sonographyof plantar fibromatosis. AJR Am J Roentgenol2002;179:1167–72.

[17] Murphey MD, McRae GA, Fanburg-Smith JC,et al. Imaging of soft-tissue myxoma withemphasis on CT and MR and comparison of


radiologic and pathologic findings. Radiology2002;225:215–24.

[18] Reynolds DL, Jacobson JA, Inampudi P, et al. Sono-graphic characteristics of peripheral nerve sheathtumors. Am J Roentgenol 2004;182:741–4.

[19] Kristina IO, Stacy GS, Montag A. Soft tissue cav-ernous hemangioma. Radiographics 2004;24:849–54.

[20] Paltiel HJ, Burrows PE, Kozakewich HP, et al.Soft tissue vascular anomalies: utility of US fordiagnosis. Radiology 2000;214:747–54.

[21] Murphey MD, Kransdorf MJ, Smith SE. Imagingof soft tissue neoplasms in the adult: malignanttumors. Semin Musculoskelet Radiol 1999;3:39–58.

[22] Bodner G, Schocke MF, Rachbauer F, et al. Differ-entiation of malignant and benign musculoskel-etal tumors: combined color and power Doppler

US and spectral wave analysis. Radiology 2002;223:410–6.

[23] Adler RS, Bell DS, Bamber JC, et al. Evaluation ofsoft tissue masses using segmented color Dopp-ler velocity images: preliminary observations.AJR Am J Roentgenol 1999;172:781–8.

[24] Kaushik S, Miller TT, Nazarian LN, et al. SpectralDoppler sonography of musculoskeletal soft tis-sue masses. J Ultrasound Med 2003;22:1333–6.

[25] Dock W, Grabenwoger F, Metz V, et al. Tumorvascularization: assessment with duplex sonog-raphy. Radiology 1991;181:241–4.

[26] Liu JC, Chiou HJ, Chen WM, et al. Sonographi-cally guided core needle biopsy of soft tissueneoplasms. J Clin Ultrasound 2004;32:294–8.

[27] Arya S, Nagarkatti DG, Dudhat SB, et al. Softtissue sarcomas: ultrasonographic evaluation oflocal recurrences. Clin Radiol 2000;55:193–7.



699

Dynamic Sonography of Jointsand Soft TissuesViviane Khoury, MDa,*, Etienne Cardinal, MDb

- Joint disordersShoulderElbowWrist and handHip

KneeAnkle

- Soft-tissue masses- Summary- References

This article reviews the wide variety of joint andsoft-tissue disorders that can be diagnosed using dy-namic sonography. We discuss dynamic maneuversthat enhance its diagnostic power and that can beeasily incorporated into the sonographic examina-tion. Many of these disorders cannot be diagnosedby any other imaging method. Sonography isa useful and rapidly evolving technique for theinvestigation of many joint and soft-tissue disor-ders. Sonography is well suited for examinationsof the musculoskeletal system because structuresare often superficial, examinations may be donein a position that is comfortable for the patient,and comparisons with the contralateral side arepossible. In addition, the real-time imaging capabil-ity of sonography is a particularly advantageousfeature, permitting dynamic evaluation of a systemof movement and locomotion. Sonography is in-creasingly recognized as complementary to cross-sectional modalities. Some disorders of muscles,tendons, nerves, and joints can best be observed—and some can only be observed—when demon-strated dynamically during motion of the extremity,muscle contraction, probe compression, or position

a Department of Radiology, McGill University Health CeCanadab Department of Radiology, Hopital St-Luc, Centre HospSt., Montreal, Quebec H2X 3J4, Canada* Corresponding author.E-mail address: [email protected] (V. Khoury


change of the patient. In this review, we discussdynamic maneuvers that can be incorporated intothe sonographic examination of each peripheraljoint and of extra-articular soft tissues.

Joint disorders

Shoulder

In shoulder impingement syndrome, pain is gener-ated when the greater tuberosity of the humerus orsoft-tissue structures (supraspinatus tendon andsubacromial-subdeltoid bursa) encroach on thecoracoacromial arch (acromion, coracoacromialligament, and acromioclavicular joint) in abduc-tion or abduction-flexion internal rotation of theshoulder. Although clinical diagnostic tests areused frequently for evaluating shoulder impinge-ment syndrome and may be helpful, they lack spec-ificity [1]. Dynamic sonography has been shown tobe a valuable diagnostic tool for making the diag-nosis of shoulder impingement. It enables clini-cians to directly visualize soft tissues during thisdynamic process, assess the severity of the impinge-ment, and evaluate the rotator cuff and other

nter, 1650 Cedar ave., Montreal, Quebec H3G 1A4,

italier de l’Universite de Montreal, 1058 Saint-Denis

).




Fig. 2. (Video S2). Calcium hydroxyapatite depositioncausing intrinsic shoulder impingement syndrome.Coronal sonogram showing large calcific depositwithin supraspinatus tendon (*) preventing passageof greater tuberosity of humerus (H) under acromion(A) during shoulder abduction.

Khoury & Cardinal700

abnormalities known to be associated with shoulderimpingement syndrome [2,3]. Two dynamic ma-neuvers may be used. For both, the transducer isplaced in the oblique coronal plane with its medialmargin at the anterolateral edge of the acromion.Then, in the first maneuver, the shoulder is abductedanterolaterally (flexion and abduction) while in in-ternal rotation. In the second maneuver, the shoul-der is abducted while in neutral position [4].

The dynamic evaluation may be used to classifythe severity of external shoulder impingementsyndrome [3]. In mild impingement, there are noobjective sonographic findings of impingementduring shoulder motion, but there is correlationbetween passage of the tendon under the acromionand painful symptoms. With moderate impinge-ment, there is accumulation of subacromial-subdeltoid bursal synovium or fluid lateral to theacromion. The supraspinatus tendon may catchon the acromion (ratchet motion) (Fig. 1 andVideo S1). With severe impingement, there is supe-rior migration of the humeral head and the tendonbunches up or bulges laterally because the greatertuberosity cannot glide under the acromial acousticshadow.

One caveat when using these dynamic maneuversis that impingement cannot be assessed in the pres-ence of frozen shoulder (adhesive capsulitis), wherethere is limitation of movement with dynamicmaneuvers in sonography [5]. However, this de-creased range of motion generally occurs beforethe tendon approaches the lateral margin of theacromion. Calcium hydroxyapatite deposition dis-ease affecting the rotator cuff tendons may alsolead to limitation of motion (Fig. 2 and Video S2).

The long head of the biceps brachii tendon maydislocate medially in the setting of a subscapularistendon tear, a supraspinatus tendon tear, or a shal-low bicipital groove. In some cases, the dislocation

Fig. 1. (Video S1). Shoulder impingement syndrome.Coronal sonogram showing bunching of subacro-mial-subdeltoid bursa (*) lateral to acromion (A)during shoulder abduction, consistent with moderateshoulder impingement syndrome. (T) Greatertuberosity.

or subluxation (where the tendon is perched on thelesser tuberosity) may be transient and seen onlywith a dynamic maneuver [6]. The biceps tendonat the level of the bicipital groove is scanned inthe transverse plane while externally rotating theshoulder. Dynamic scanning is of interest in caseswhere the abnormality is transient, with the tendonbeing in its normal location in the bicipital groovewhile in the neutral position and subluxing or dis-locating during external rotation. Less commonly,the reverse is seen. That is, subluxation or disloca-tion occurs upon return to the neutral position.

Occasionally anterior or posterior glenohumeraljoint instability may be demonstrated with sonog-raphy. During shoulder movement, glenohumeralinstability may be spontaneously demonstratedon sonography as joint malalignment or exagger-ated motion of the humeral head relative to glenoid(Fig. 3 and Video S3).

An acromioclavicular joint injury is typicallyevaluated with comparative radiographs with andwithout applied stress. However sonography hasbeen shown to be superior and should be used inconjunction with radiographs in the evaluation ofacromioclavicular joint injury [7,8]. In high-gradeacromioclavicular sprains, sonography can evaluatesoft-tissue involvement, which is relevant for preop-erative assessment, while visualizing joint wideningwith movement, usually flexion and extension ofthe shoulder or applied stress (Fig. 4 and VideoS4) [6,7]. Mild to moderate sprains may be difficultto diagnose on radiographs, and their clinicalsequelae are likely underestimated. Peetrons andBedard [9] suggest the cross-arm maneuver asa very useful technique in the sonographic detec-tion of these lower-grade sprains. During dynamicexamination of the acromioclavicular joint, therelationship between the acromion and clavicle

Fig. 3. (Video S3). Anterior glenohumeral joint insta-bility. Transverse sonogram at the posterior aspectof the glenohumeral joint shows exaggerated ante-rior motion of the humerus (H) relative to glenoid(G) with shoulder motion suggesting anteriorinstability.

Dynamic Sonography of Joints and Soft Tissues 701

should change minimally (<1 mm) when the ipsi-lateral hand is placed onto the opposite shoulder.If the acromioclavicular ligament is stretched ortorn, the distance decreases during this maneuver,with possible bony contact. When the arm is movedback to the initial position, the acromioclaviculardistance increases [9]. Comparison to the contralat-eral side may be important given the presence ofanatomic variations of the acromioclavicular joint.The differential diagnosis for widening of the acro-mioclavicular joint includes osteoarthritis [10],though differentiating it from injury can generallybe done clinically.

With snapping scapula, the patient complains ofan audible snapping sound that may or may not beassociated with pain. Snapping scapula is usuallyan idiopathic condition of the scapulothoracic

Fig. 4. (Video S4). Acromioclavicular joint instability.Coronal sonogram of right acromioclavicular jointshows abnormal widening between acromion (ACRO)and clavicle (CLAV) during shoulder motion.

articulation, though it may be caused by skeletalor soft-tissue abnormalities [11]. Bony abnormali-ties associated with this syndrome include osteo-chondroma, rib and scapular bone deformities,and abnormal scapular angulation. Soft-tissuecauses include bursitis, interstitial myofibrosis,and muscle atrophy. Three-dimensional CT hasbeen described in the evaluation of this syndrome[12] as has fluoroscopy. Sonography, which avoidsradiation in the generally young population af-fected by this condition, may be ideally suited asa first-line technique along with radiographs. Theabnormal, often jerking, movement of the scapulaagainst the rib cage can be directly visualized, ascan certain underlying causes (Fig. 5 and Video S5).

Ultrasound is a reliable, sensitive, and widelyused modality for assessing rotator cuff tears [13].One pitfall in the evaluation of tendon tears is thepresence of fluid and synovial hypertrophy fillingthe gap that can mimic a hypoechoic but intact ten-don. Dynamic compression with the transducerinduces shift of the fluid and synovial hypertrophyaway from the tear, allowing for accurate diagnosis(Fig. 6).

Elbow

In ulnar nerve dislocation, the nerve slides out ofthe cubital tunnel and over the medial epicondyleof the humerus during elbow flexion. Ulnar nervedislocation has been reported in approximately16% of healthy subjects [14]. For dynamic sonogra-phy, the ulnar nerve is scanned in the transverseplane during flexion and extension of the elbow,normally positioned posterior to the medial epi-condyle apex. With ulnar nerve dislocation, theabrupt medial displacement of the nerve over themedial epicondyle produces a snapping sensationfelt through the transducer (Fig. 7 and Video S7).The position of the hypoechoic medial muscle belly

Fig. 5. (Video S5). Snapping scapula. Sagittal sono-gram shows abnormal grating movement of scapulaagainst ribs during motion.

Fig. 6. Supraspinatus full-thickness cuff tear. (A) Coronal-oblique sonogram of supraspinatus tendon showshypoechoic region in its distal aspect with a preserved convexity (arrows); the appearance may be mistakenfor an intact tendon with severe tendinopathy. (B) With probe compression, the convex region flattens (solidarrows), revealing a full-thickness tear of the supraspinatus tendon with retraction (dashed arrow). (H) Greatertuberosity of humerus.


of the triceps should also be assessed for abnormalsnapping over the medial epicondyle with elbowflexion (snapping triceps syndrome) because itmay coexist with ulnar nerve dislocation (Fig. 8and Video S8) [15]. It is important not to apply ex-cessive transducer pressure, which may mask thediagnosis by inhibiting the ulnar nerve from dislo-cating [15].

The elbow is a common site of intra-articularbodies, which are usually found in the anterior orposterior joint recesses. Some of these are not ap-parent on conventional radiographs because theyare in locations that make them difficult to identify,are especially small, or are cartilaginous in nature.Sonography is accurate in detecting, characterizing,and localizing these intra-articular bodies in thejoint [16,17]. Intra-articular bodies appear as hy-perechoic foci with or without posterior acousticshadowing (Fig. 9). When fluid is present, loosebodies can be mobilized with probe pressure orflexion and extension of the joint. Mobilization ofthese hyperechoic foci using dynamic maneuversdifferentiates them from synovial calcifications

Fig. 7. (Video S7). Ulnar nerve dislocation. Transverseultrasound during elbow flexion shows abrupt dislo-cation of hypoechoic oval nerve over medial epicon-dyle and superficial to common flexor tendoninsertion, correlating with the clinical snap. (E) Epi-condyle. (Arrowhead) Dislocated ulnar nerve. (*)Original (anatomic) position of nerve.

and osteophytes. Sonography can also be used toexamine for intra-articular bodies in other periph-eral joints.

The anterior band of the ulnar collateral ligament(UCL) is the major stabilizer of the elbow jointagainst valgus stress [18]. Both MR imaging andultrasound have been shown to accurately evaluatestructural abnormalities of the UCL [19–21]. Anadvantage of sonography is that it can also demon-strate associated joint instability, an important partof the evaluation of the UCL. Moreover, sonogra-phy avoids the invasiveness of MR arthrography,which has been shown to be more accurate thanconventional MR imaging for evaluation of theUCL [19]. Laxity of the UCL can be assessed bycomparing the width of the ulnohumeral joint atrest with that during application of valgus stressto the joint [22]. There is widening of the jointwith stress in the presence of instability due toUCL laxity.

Fig. 8. (Video S8). Snapping triceps syndrome. Trans-verse ultrasound during elbow flexion shows disloca-tion of a hypoechoic, enlarged ulnar nerve (arrows)and medial head of the triceps brachii muscle (T)over the medial epicondyle (E). (Courtesy of J. Jacob-son, MD, Ann Arbor, MI.)

Fig. 9. Elbow intra-articular osseous body. (A) Longitudinal sonogram of the anterior aspect of the elbow jointshows a normal anterior joint recess with a minimal amount of hypoechoic fluid. (B) Longitudinal sonogram ofthe contralateral elbow shows an intra-articular hyperechoic osseous body (arrows) surrounded by fluid in theanterior joint recess. (H) Humerus. (R) Radius.


Tendons around hardwareJoints, such as the elbow, are common sites of frac-tures fixed by open reduction and internal fixation.Unlike CT and MR imaging, sonography of soft tis-sue around hardware is not degraded by metallic ar-tifact. Dynamic sonography can be used for theidentification of tendons impinging on plates orscrews (Fig. 10 and Video S10).

Wrist and hand

Trigger finger is usually diagnosed clinically whena patient presents with symptomatic locking orclicking of a finger or thumb. The condition isa mechanical problem caused by a mismatchbetween the relative size of the flexor tendon andits sheath, most often due to tendinosis and teno-synovitis [23]. Traumatic laceration of the flexortendon is an extremely rare cause [24]. Sonographyis more often requested to guide corticosteroidinjection, though the intervention should alwaysbe preceded by a diagnostic examination. Sonogra-phy may also be requested for recurrent symptoms

Fig. 10. (Video S10). Protruding screw in elbow joint.Transverse sonogram of elbow shows screw in radialhead protruding into the joint (arrow) and annularligament during pronation and supination of theelbow. (R) Radius.

postoperatively. Findings on sonography of theflexor tendon may include tendon thickening, al-tered echotexture, diffuse or focal thickening ofthe synovial sheath, associated peritendinous cysts,or a thickened A1 (annular) pulley [25–27]. Fordynamic sonography, the flexor tendon of the fingeris scanned longitudinally at the level of the metacar-pophalangeal joint during active flexion and exten-sion. In trigger finger, the tendon catches duringmovement, instead of gliding smoothly (Fig. 11and Video S11). Impingement of the thickenedsegment of the tendon and its synovial sheath onthe A1 pulley can be seen. Comparison with anunaffected digit may be helpful. The tendon isalso examined on longitudinal and transverse scan-ning for associated tenosynovitis, peritendinouscysts, and thickening of the A1 pulley.

Finger pulley injuries have been noted to be fre-quent in rock climbers [28] and may be difficult

Fig. 11. (Video S11A and S11B). Trigger finger. Longi-tudinal sonogram of normal finger at level ofmetacarpophalangeal joint (MCP) shows focal teno-synovitis (TS) on palmar aspect of flexor tendon (T)and thickened A1 pulley. Video S11A shows normal,smooth movement of flexor tendon with flexionand extension. Video S11B shows hesitation of flexortendon movement during extension.

Fig. 13. (Video S13). Snapping iliopsoas tendon. Obli-que transverse scan above acetabular margin of lefthip shows oval hyperechoic tendon (arrows) withsurrounding hypoechoic muscle. Video S13 of sameregion shows abnormal jerking of the hyperchoiciliopsoas tendon during the dynamic maneuver.

Fig. 12. (Video S12). Snapping extensor carpi ulnaristendon. Transverse sonogram of dorsal and ulnaraspect of wrist shows dislocation of extensor carpiulnaris (ECU) tendon out of its groove. (*) Normal(anatomic) position of tendon. (U) Ulna. Video S12shows sonogram of same region during pronationand supination demonstrating abnormal, abruptmovement of extensor carpi ulnaris tendon in andout of the ulnar groove.

Fig. 14. (Video S14). Snapping meniscus. Coronalultrasound of medial aspect of the femorotibial jointshows heterogeneous torn meniscus. Video S14shows abnormal jerking movement of the meniscusduring flexion and extension.


to diagnose clinically. Sonography is well suited toevaluate the small structures of the fingers and isable to directly visualize the bowstringing of theflexor tendon that results from interruption ofa pulley. Dynamic assessment may be done by mea-suring the distance between flexor tendon andphalanx at the levels of the A2 and A4 pulleys dur-ing active forced finger flexion against resistance ofthe sonographer’s finger [29]. A distance of greaterthan 1 mm indicates a pulley injury [30]. In ‘‘boxerknuckle’’ due to traumatic disruption of the exten-sor hood, the extensor tendon may be examinedfor dislocation during active finger flexion andextension with dynamic sonography [4]. Similarly,dynamic imaging with the hand in pronation andsupination may show subluxation or dislocationof the extensor carpi ulnaris from its groove in thedistal ulna, as well as associated tenosynovitis ortendon tear (Fig. 12 and Video S12).

Several investigators have shown that sonogra-phy is comparable to electrodiagnostic studies indiagnosis of carpal tunnel syndrome [31–34]. Onestudy demonstrated that during passive flexionand extension of the index finger, the median nervehad significantly less transverse sliding beneath theflexor retinaculum in patients with carpal tunnelsyndrome [35].

Hip

Snapping hip syndrome refers to an audible snap inthe hip during motion associated with pain. Extra-articular causes include snapping of the iliopsoastendon, friction of the iliotibial tract or gluteusmaximus against the greater trochanter, and snap-ping of the iliofemoral ligament over the femoralhead [36]. Intra-articular causes include labral tears,

intra-articular bodies, osteochondral fractures, andtransient subluxation of the femoral head. Sonogra-phy is well suited to evaluate the snapping hip be-cause it can reveal the abnormality and establishits immediate temporal correlation with the gener-ation of painful symptoms [37]. To examine foriliopsoas tendon snapping, the transducer is placedanteriorly in a transverse or oblique transverseplane just above the hip joint as the patient per-forms the motion that produces the snap. This usu-ally involves passage of a flexed, abducted, andexternally rotated hip back to full extension, withthe snap occurring about halfway during motion.On sonography, there is an abrupt lateromedial

Fig. 15. (Video S15). Snapping knee with prosthesis. (A) Coronal ultrasound of medial side of knee (oriented onits side) shows abnormal position of polyethylene component (hyperechoic line) relative to metallic tibialcomponent (hyperechoic line with ring-down artifact). Video S15 shows abnormal movement of polyethylenecomponent relative to tibia during knee flexion and extension. (B) Anteroposterior radiograph of knee (onits side) zoomed in on its medial aspect to show orientation of sonogram.


and rotatory motion of the iliopsoas tendon over itsmuscle during the dynamic maneuver (Fig. 13 andVideo S13). Rarely, an underlying paralabral cystmay be associated with a snapping iliopsoas ten-don. To examine for iliotibial tract snapping, thepatient lies on the side of the normal hip as theabnormal hip is scanned transversely during flexionand extension. The normal iliotibial tract (coursinglaterally to the trochanter and distal gluteus mediustendon) glides smoothly over the greater trochanterduring hip motion. In iliotibial tract snapping,there is abnormal jerking movement of the ilioti-bial tract as it abruptly snaps over the greatertrochanter. Occasionally, the patient needs to beexamined in a standing position, with gluteusmaximus contraction, to produce the iliotibial tractsnap [38].

Fig. 16. (Video S16). Loose polyethylene particles intotal knee arthroplasty. Transverse sonogram of pos-terior aspect of knee shows hyperechoic linear fociwithin a popliteal recess (arrows). Video S16 showsmotion of these particles with slight knee flexionand extension.

Knee

Snapping knee syndrome refers to a painful snapduring knee motion and can be caused by a hetero-geneous group of disorders. This syndrome may beprovoked by abnormal tendon motion over thebony structures of the knee. Medially, snappinghas been reported by gracilis or semitendinosus[38], and laterally by biceps femoris tendon dueto an anomalous insertion on the fibula or proxi-mal tibia [39,40], or by popliteus tendon in itsgroove [41,42]. Snapping knee may also be causedby an intra-articular nodular mass in rheumatoid

Fig. 17. (Video S17). Peroneus longus dislocation.Transverse ultrasound over fibula with dorsiflexionand eversion of the foot shows dislocation of theperoneus longus tendon (PL) anterolaterally over thelateral malleolus (LM). Note tear of superior peronealretinaculum (arrow). (PB, peroneus brevis tendon).Dislocation was present only during dynamic maneu-vers and not apparent with ankle in neutral position.(Courtesy of J. Jacobson, MD, Ann Arbor, MI.)

Fig. 18. (Video S18). Achilles tendon full-thicknesstear. Ultrasound longitudinal to the Achilles tendonshows tendon discontinuity (between arrows). VideoS18 shows movement of the distal stump and nomovement of the proximal stump with dorsiflexionand plantar flexion. (Courtesy of J. Jacobson, MD,Ann Arbor, MI.)


arthritis. At sonography, the mass can be identifiedbecause it appears to jump and slip in and out ofthe patellofemoral articulation during flexion andextension [43]. Other causes of snapping kneesyndrome for which dynamic ultrasound may beparticularly well suited for evaluation include tornmeniscus (Fig. 14 and Video S14), loosened poly-ethylene component after total knee arthroplasty(Fig. 15 and Video S15) [44], and intra-articularloose bodies. Loosened particles from polyethylenewear floating in the joint may be detected, appear-ing as hyperechoic lines parallel to the transducerplane (Fig. 16 and Video S16) [45].

Ankle

Most cases of peroneal tendon dislocation are dueto posttraumatic disruption of the superior pero-neal retinaculum stemming from sudden dorsiflex-ion and eversion of the ankle. These cases may beacute or chronic [46]. Diagnosis, which may be dif-ficult clinically, is important because prompt surgi-cal repair is the preferred treatment [47]. Because

Fig. 19. (Videos S19A and S19B). Normal ankle ligaments.calcaneofibular ligaments with gentle ankle dorsiflexionbecoming more taut, allowing for improved fiber visuaPeroneal tendons.

the tendons often are in their anatomic positionat rest, static imaging techniques, such as CT andMR imaging, cannot reliably document episodicor transient dislocation [48]. Dynamic sonographyis ideally suited and has been shown to be an effec-tive technique for the diagnosis of peroneal tendondislocation [4,49]. The transducer is focused on theretromalleolar groove of the fibula in the transverseplane while the ankle is actively or passively dorsi-flexed and everted; the sonographer may need toapply an opposing force on the lateral aspect ofthe hindfoot [4]. The peroneal tendons shouldmaintain their normal position posterior to the lat-eral malleolus. In peroneal tendon subluxation ordislocation, the peroneal tendons are displacedlateral to the fibula during the dynamic maneuvers(Fig. 17 and Video S17). There may be passage ofone tendon, both tendons, or only one bundle ofa longitudinally split tendon anterolaterally overthe lateral malleolus. The tendons may also remainin the fibular groove but reverse position on eachother, a condition termed retromalleolar intra-sheath subluxation, which is essentially only diag-nosable by dynamic sonography [48,50].

Dynamic sonography may also be used to differ-entiate between partial and full-thickness tears ofa tendon, such as with Achilles tendon tears. Thisbecomes important in the setting of a subacute orclinically missed Achilles tendon tear where itmay be difficult to differentiate a partial tear froma full-thickness tear or from a healing of a tear onstatic ultrasound images (Fig. 18 and Video S18).With dorsiflexion and plantar flexion at the ankleunder sonographic visualization, movement ofone tendon stump away from the other indicatesfull-thickness tear and no continuous tendon fibers.In contrast, continuous translation of tendonmovement across the site of the tendon tear indi-cates some intact fibers.

Ankle ligament ruptures are best diagnosed byphysical examination in most cases [51]. However,sonography may be used in patients with equivocal

Sonograms of (A) normal anterior tibiofibular and (B)and with inversion of the hindfoot showing ligamentlization. (Arrows) Ligament. (T) Tibia. (F) Fibula. (P)

Fig. 20. Subcutaneous li-poma. Sonogram of subcu-taneous tissues shows anelliptic, well-defined mass(arrows) that is compress-ible, shown with (right)and without (left) trans-ducer pressure.


acute or chronic lesions with persistent pain[52,53]. Changing the position of the ankle andstretching the ligaments by using dynamic maneu-vers can avoid anisotropy and improve ligamentvisualization on sonography. Thus, the anteriortalofibular ligament is better seen with ankle dorsi-flexion with inversion of the hindfoot; the deltoidligament is better seen with gentle dorsiflexionand eversion stress on the hindfoot (Fig. 19 andVideo S19) [52,54].

Soft-tissue masses

Dynamic maneuvers can aid in the diagnosis ofseveral soft-tissue disorders. Compression with thetransducer is especially helpful. Subcutaneouslipomas typically exhibit an elliptic shape, shortlinear striations that run parallel to the skin, and

Fig. 21. (Video S21). Hematoma. Longitudinal sono-gram of calf muscles shows a heterogeneous, oval hy-poechoic complex intramuscular mass. Compressionwith the transducer shows swirling of the liquefiedcontents of the mass, in this case representinga hematoma.

a characteristic compressibility, a feature thatincreases confidence in their sonographic diagnosis(Fig. 20).

Compression also confirms the liquefied contentof a soft-tissue lesion. A compressible liquefied soft-tissue lesion may represent a hematoma, abscess, ornecrotic tumor (Fig. 21 and Video S21).

Venous malformations, previously referred to ashemangiomas, appear as hypoechoic serpiginousvessels with sluggish flow surrounded by hypere-choic fat. Dynamic compression generates increasedcolor signal in these channels, confirming the vascu-lar nature of the lesion (Fig. 22 and Video S22).Venous malformations of the lower extremity canalso be made more conspicuous by examining thelesion with the patient standing [55].

Fig. 22. (Video S22). Venous malformation. Ultra-sound of calf muscle showing typical appearance,with hyperechoic fat, multiple dilated hypoechoicserpiginous vessels, and sluggish flow (and hencelittle signal on color Doppler). There is increased colorsignal with dynamic compression with transducer.

Fig. 23. (Video S23). Pseudomass due to chronic mus-cle tear. Longitudinal sonogram of quadriceps muscleduring isometric contraction demonstrates proximalretraction and bulging of muscle, secondary toa chronic tear more distally, simulating a mass (M).


Dynamic sonography is well suited to diagnosea pseudomass due to a chronic muscle tear. Theremay be associated focal atrophy associated withsuch a tear, leading to areas of muscle asymmetrythat mimic a mass. Scanning during isometric mus-cle contraction shows partial retraction of the prox-imal segment of the torn muscle, causing a focalbulging (Fig. 23 and Video S23).

Summary

Dynamic maneuvers can be easily integrated in thesonographic evaluation of a wide variety of muscu-loskeletal disorders. All the peripheral joints, as wellas extra-articular soft tissues, have disorders thatare best shown dynamically (ie, during motion,muscle contraction, probe compression, or posi-tion change of the patient). Several of these disor-ders cannot be diagnosed by any other imagingmethod.

References

[1] Calis M, Akgun K, Birtane M, et al. Diagnosticvalues of clinical diagnostic tests in subacromialimpingement syndrome. Ann Rheum Dis 2000;59:44–7.

[2] Farin PU, Jaroma H, Harju A, et al. Shoulderimpingement syndrome: sonographic evalua-tion. Radiology 1990;176:845–9.

[3] Chhem RK, Cardinal E. Guidelines and gamutsin musculoskeletal ultrasound. New York: Wi-ley-Liss; 1999.

[4] Khoury V, Cardinal E, Bureau NJ. Musculoskele-tal sonography: a dynamic tool for usual andunusual disorders. AJR Am J Roentgenol 2007;188:W63–73.

[5] Ryu KN, Lee SW, Rhee YG, et al. Adhesive capsu-litis of the shoulder joint: usefulness of dynamicsonography. J Ultrasound Med 1993;12:445–9.

[6] Farin PU, Jaroma H, Harju A, et al. Medialdisplacement of the biceps brachii tendon: eval-uation with dynamic sonography duringmaximal external shoulder rotation. Radiology1995;195:845–8.

[7] Heers G, Hedtmann A. Correlation of ultrasono-graphic findings to Tossy’s and Rockwood’sclassi-fication of acromioclavicular joint injuries.Ultrasound Med Biol 2005;31:725–32.

[8] Lind T, Reimann I, Larsen JK, et al. Sonographyin soft-tissue trauma of the shoulder. ActaOrthop Scand 1989;60:49–53.

[9] Peetrons P, Bedard JP. Acromioclavicular jointinjury: enhanced technique of examinationwith dynamic maneuver. J Clin Ultrasound2007;35:262–7.

[10] Alasaarela E, Tervonen O, Takalo R, et al. Ultra-sound evaluation of the acromioclavicular joint.J Rheumatol 1997;24:1959–63.

[11] Carlson HL, Haig AJ, Stewart DC. Snapping scap-ula syndrome: three case reports and an analysisof the literature. Arch Phys Med Rehabil 1997;78:506–11.

[12] Mozes G, Bickels J, Ovadia D, et al. The use ofthree-dimensional computed tomography inevaluating snapping scapula syndrome. Ortho-pedics 1999;22:1029–33.

[13] Teefey SA, Rubin DA, Middleton WD, et al. De-tection and quantification of rotator cuff tears.Comparison of ultrasonographic, magnetic reso-nance imaging, and arthroscopic findings inseventy-one consecutive cases. J Bone Joint SurgAm 2004;86-A:708–16.

[14] Childress HM. Recurrent ulnar-nerve dislocationat the elbow. Clin Orthop Relat Res 1975;108:168–73.

[15] Jacobson JA, Jebson PJ, Jeffers AW, et al. Ulnarnerve dislocation and snapping triceps syn-drome: diagnosis with dynamic sonography—report of three cases. Radiology 2001;220:601–5.

[16] Bianchi S, Martinoli C. Detection of loose bodiesin joints. Radiol Clin North Am 1999;37:679–90.

[17] Frankel DA, Bargiela A, Bouffard JA, et al. Syno-vial joints: evaluation of intraarticular bodieswith US. Radiology 1998;206:41–4.

[18] Schwab GH, Bennett JB, Woods GW, et al. Bio-mechanics of elbow instability: the role of themedial collateral ligament. Clin Orthop RelatRes 1980;146:42–52.

[19] Cotten A, Jacobson J, Brossmann J, et al. Collat-eral ligaments of the elbow: conventional MRimaging and MR arthrography with coronal obli-que plane and elbow flexion. Radiology 1997;204:806–12.

[20] Popovic N, Ferrara MA, Daenen B, et al. Imagingoveruse injury of the elbow in professional teamhandball players: a bilateral comparison usingplain films, stress radiography, ultrasound, and


magnetic resonance imaging. Int J Sports Med2001;22:60–7.

[21] Ferrara MA, Marcelis S, Popovic N, et al. Modifi-cations of the elbow induced by the practice ofhandball on radiography, US and MRI. JBR-BTR1999;82:222–7.

[22] Nazarian LN, McShane JM, Ciccotti MG, et al.Dynamic US of the anterior band of the ulnarcollateral ligament of the elbow in asymptom-atic major league baseball pitchers. Radiology2003;227:149–54.

[23] Ryzewicz M, Wolf JM. Trigger digits: principles,management, and complications. J Hand Surg[Am] 2006;31:135–46.

[24] Fujiwara M. A case of trigger finger followingpartial laceration of flexor digitorum superficialisand review of the literature. Arch Orthop TraumaSurg 2005;125:430–2.

[25] Serafini G, Derchi LE, Quadri P, et al. Highresolution sonography of the flexor tendons intrigger fingers. J Ultrasound Med 1996;15:213–9.

[26] Sampson SP, Badalamente MA, Hurst LC, et al.Pathobiology of the human A1 pulley in triggerfinger. J Hand Surg [Am] 1991;16:714–21.

[27] Boutry N, Titecat M, Demondion X, et al. High-frequency ultrasonographic examination of thefinger pulley system. J Ultrasound Med 2005;24:1333–9.

[28] Rooks MD, Johnston RB 3rd, Ensor CD, et al.Injury patterns in recreational rock climbers.Am J Sports Med 1995;23:683–5.

[29] Klauser A, Frauscher F, Bodner G, et al. Finger pul-ley injuries in extreme rock climbers: depictionwith dynamic US. Radiology 2002;222:755–61.

[30] Hauger O, Chung CB, Lektrakul N, et al. Pulleysystem in the fingers: normal anatomy andsimulated lesions in cadavers at MR imaging,CT, and US with and without contrast materialdistention of the tendon sheath. Radiology2000;217:201–12.

[31] Lee D, van Holsbeeck MT, Janevski PK, et al.Diagnosis of carpal tunnel syndrome. Ultra-sound versus electromyography. Radiol ClinNorth Am 1999;37:859–72.

[32] Visser LH, Smidt MH, Lee ML. High-resolutionsonography versus EMG in the diagnosis ofcarpal tunnel syndrome. J Neurol Neurosurg Psy-chiatry 2008;79(1):63–7.

[33] Wong SM, Griffith JF, Hui AC, et al. Carpaltunnel syndrome: diagnostic usefulness of so-nography. Radiology 2004;232:93–9.

[34] Abicalaf CA, de Barros N, Sernik RA, et al. Ultra-sound evaluation of patients with carpal tunnelsyndrome before and after endoscopic releaseof the transverse carpal ligament. Clin Radiol2007;62:891–4.

[35] Nakamichi K, Tachibana S. Restricted motion ofthe median nerve in carpal tunnel syndrome. JHand Surg [Br] 1995;20:460–4.

[36] Schaberg JE, Harper MC, Allen WC. The snap-ping hip syndrome. Am J Sports Med 1984;12:361–5.

[37] Pelsser V, Cardinal E, Hobden R, et al. Extraartic-ular snapping hip: sonographic findings. AJR AmJ Roentgenol 2001;176:67–73.

[38] Bae DK, Kwon OS. Snapping knee caused by thegracilis and semitendinosus tendon. A case re-port. Bull Hosp Jt Dis 1997;56:177–9.

[39] Lokiec F, Velkes S, Schindler A, et al. The snap-ping biceps femoris syndrome. Clin Orthop Re-lat Res 1992;205–6.

[40] Kissenberth MJ, Wilckens JH. The snapping bicepsfemoris tendon. Am J Knee Surg 2000;13:25–8.

[41] Cooper DE. Snapping popliteus tendon syn-drome. A cause of mechanical knee popping inathletes. Am J Sports Med 1999;27:671–4.

[42] McAllister DR, Parker RD. Bilateral subluxatingpopliteus tendons. A case report. Am J SportsMed 1999;27:376–9.

[43] Torisu T, Yosida S, Takasita M. Painful snappingin rheumatoid knees. Int Orthop 1997;21:361–3.

[44] Segal A, Miller TT, Krauss ES. Fabellar snappingas a cause of knee pain after total knee replace-ment: assessment using dynamic sonography.AJR Am J Roentgenol 2004;183:352–4.

[45] Guillin R, Laporte JL, Sabouret P, et al. Polyethyl-ene wear in knee arthroplasty: sonographic find-ings. Journal of Ultrasound in Medicine 2008;27(2):275–9.

[46] Safran MR, O’Malley D Jr, Fu FH. Peronealtendon subluxation in athletes: new exam tech-nique, case reports, and review. Med Sci SportsExerc 1999;31:S487–92.

[47] Maffulli N, Ferran NA, Oliva F, et al. Recurrentsubluxation of the peroneal tendons. Am JSports Med 2006;34:986–92.

[48] Neustadter J, Raikin SM, Nazarian LN. Dynamicsonographic evaluation of peroneal tendon sub-luxation. AJR Am J Roentgenol 2004;183:985–8.

[49] Morvan G, Busson J, Wybier M, et al. Ultrasoundof the ankle. Eur J Ultrasound 2001;14:73–82.

[50] McConkey JP, Favero KJ. Subluxation of theperoneal tendons within the peroneal tendonsheath. A case report. Am J Sports Med 1987;15:511–3.

[51] van Dijk CN, Mol BW, Lim LS, et al. Diagnosis ofligament rupture of the ankle joint. Physicalexamination, arthrography, stress radiographyand sonography compared in 160 patients afterinversion trauma. Acta Orthop Scand 1996;67:566–70.

[52] Peetrons P, Creteur V, Bacq C. Sonography ofankle ligaments. J Clin Ultrasound 2004;32:491–9.

[53] Brasseur JL. [Ligament pathology of the anklejoint]. JBR-BTR 2003;86:96–101 [in French].

[54] Khoury V, Guillin R, Dhanju J, et al. Ultrasonog-raphy of ankle and foot: overuse and sports in-juries. Seminars in Musculoskeletal Radiology2007;11(2):149–61.

[55] Trop I, Dubois J, Guibaud L, et al. Soft-tissuevenous malformations in pediatric and youngadult patients: diagnosis with Doppler US. Radi-ology 1999;212:841–5.



711

Inguinal Region HerniasDavid A. Jamadar, MB, BSa,*, Michael G. Franz, MDb

- Anatomy- Sonographic anatomy- Ultrasound technique—general- Ultrasound technique—specific- Pitfalls

The absence of movementMovement of the spermatic cordMovement of the normal intra-abdominal

contentsIliopsoas movementDirect inguinal hernia simulating an

indirect inguinal herniaPitfalls from sonographic technique

- Complications- The incisional hernia- Clinical diagnostic dilemmas- Repair of inguinal hernias- Sonographic evaluation following mesh

repair- Limitations of sonography- The sports hernia- Ultrasound of hernias—a general

surgeon’s perspective- Summary- Acknowledgments- References

A hernia is the protrusion of a part or structure Diagnosis historically has been by clinical
through the tissues normally containing it. Inguinalhernias have been recognized for centuries [1]. Firstdocumented efforts to treat hernias surgically wereby the ancient Greek physicians [2], where if con-servative treatment failed, the physician would pro-ceed to surgery. Collectively, surgery for abdominalwall hernias account for one of the more commongroups of major operations performed by generalsurgeons, with almost 800,000 inguinal herniarepairs performed in the United States in 2003[3,4]. Inguinal hernias are the most common ofthe abdominal hernias, and although exact num-bers are unknown, about 500,000 are identified an-nually in the United States [5]. More than 25% ofmen in the United States could be expected tohave a medically identifiable inguinal hernia [5],their incidence being less in women at 3% [6]. Fem-oral hernias, however, are found more frequently inwomen [7,8].
a Department of Radiology, TC 2910, University of MichArbor, MI 48109, USAb Department of Surgery, TC 2210H, University of MichiArbor, MI 48109 - 5329, USA* Corresponding author.E-mail address: [email protected] (D.A. Jamada


methods, but more recently, imaging has playedmore of a role as a primary diagnostic tool and toidentify complications. Imaging has been foundto be particularly useful in identifying those pa-tients where clinical examination for diagnosis ofan inguinal hernia may be normal or equivocal.In these patients, ultrasound has been shown tobe an accurate imaging modality for making the di-agnosis [9]. Diagnosis of a hernia is important, butthe diagnosis of pathology that mimics a hernia ofthe inguinal region may be equally important [10],particularly in planning the management of thepatient.

Anatomy

The gross anatomy of the inguinal region is com-plex [11]. The anterior inferior abdominal wall iswhere the spermatic cord (round ligament in

igan Hospitals, 1500 East Medical Center Drive, Ann

gan Hospitals, 1500 East Medical Center Drive, Ann

r).




Jamadar & Franz712

a female) and pelvic vessels pass from within theabdominal cavity to an extra-abdominal location,resulting in the development of complex mecha-nisms to retain the intra-abdominal contents. Fail-ure of this mechanism results in areas of weaknessin the inguinal region, through which herniaspass [12]. Any anatomic or surgical text will de-scribe the inguinal anatomy in great detail. Fortu-nately, the sonographic anatomy is much lesscomplex and will be described here.

Fig. 2. 27-year-old man with normal anatomy. Axialimage at the lateral margin of the rectus abdominismuscle (R) where the inferior epigastric artery andveins (arrows) have just crossed the linea semilunaris(*). Left is medial. Abbreviation: F, flank muscles.

Sonographic anatomy

The musculoskeletal sonographer relies on thebony anatomy for anatomic orientation and thechallenge of the inguinal region is in the paucityof bony landmarks. This notwithstanding, the au-thors have found that the inferior epigastric arteryand the pubic tubercle [13,14] are the only land-marks needed to diagnose and differentiate be-tween the direct and indirect inguinal and femoralhernias (Fig. 1). The first of these, the inferior epi-gastric artery, is identified easily by sonography,while the second, although palpable in the averagepatient, also may be identified by sonography.

The inferior epigastric artery can be identified atthe lateral border of the rectus abdominis muscle.where it crosses deep to that muscle (Fig. 2).Once the artery is identified here, it usually can befollowed to its origin from the external iliac artery

Fig. 1. (Line) The right inguinal anatomy as seen fromwithin the abdominal cavity. The lateral border of therectus abdominis muscle (Rect), the inferior epigastricartery (straight arrows), and the medial inguinal liga-ment (arrowheads) define the borders of Hesselbach’striangle (H). The inguinal ligament originates fromthe anterior superior iliac spine (S) and inserts onthe pubic tubercle (T). Abbreviations: F, femoral ca-nal, Ram, superior pubic ramus and the curved arrowindicates the opening of the deep inguinal ring.

just before the inguinal ligament crosses the latter.This anatomic point is important, as immediatelydistal to the origin of the inferior epigastric arteryfrom the external iliac artery is the inguinal liga-ment as it crosses the external iliac artery/femoralartery. If the transducer is angled along a linefrom the origin of the inferior epigastric artery tothe pubic tubercle, this marks the approximate an-atomic location of the medial part of the inguinalligament that forms the inferior boundary of Hes-selbach’s triangle. When seen, the inguinal ligamentis a narrow linear structure with a tightly packed fi-brillar pattern (Fig. 3).

Hesselbach’s triangle is bounded by the inguinalligament inferiorly, the inferior epigastric artery lat-erally, and the lateral border of the rectus

Fig. 3. 27-year-old man with normal anatomy. Obli-que axial scan over the inguinal region parallel toand directly over the inguinal ligament, shows ana-tomic relationship of external iliac artery (A) andvein (V) to inguinal ligament (arrows). Right is me-dial. Abbreviation: Pec, pectineus muscle.

Fig. 4. 40-year-old man with a left sided direct inguinal hernia. The scan is in the axial plane. Left is medial. (A)The pre-Valsalva scan shows the inferior epigastric artery (curved arrow) and peritoneal fat stripe (straight ar-rows). (B) During the Valsalva maneuver, a direct hernia (straight arrows) is visualized, deforming the peritonealreflection, with movement toward the transducer. The hernia is medial to the inferior epigastric artery (curvedarrow). Note that the hernia is more superficial (closer to the transducer) than the inferior epigastric arteryduring the Valsalva maneuver.

Inguinal Region Hernias 713

abdominis muscle medially (see Fig. 1). Knowledgeof these anatomic landmarks allows one to diag-nose the inguinal hernias that may be found. Thisrelatively simple sonographic anatomic perspectiveis all that is needed, for the most part, to under-stand and diagnose the different varieties of ingui-nal hernias.

The inguinal hernias are defined by the locationof their necks. The neck of an inguinal hernia is atthe defect in the abdominal wall, through whichthe herniating contents pass. A direct inguinalhernia has its neck in Hesselbach’s triangle (see

Fig. 5. 40-year-old woman with a right indirect ingui-nal hernia that consists of extraperitoneal fat (F). Theneck (N) of the hernia is immediately lateral to the in-ferior epigastric artery (curved arrow). The transducerhas been angled to parallel the inguinal canal, andimages the lateral inguinal canal. Right is medial.

Fig. 1; Fig. 4). An indirect inguinal hernia has itsneck lateral to the inferior epigastric artery andjust cranial to the inguinal ligament at the deep in-guinal ring (see Fig. 4; Figs. 5 and 6). The femoralhernia has its neck caudad to the inguinal ligamentand usually medial to the femoral vein (Fig. 7). Al-though a spigelian hernia (Fig. 8) is not strictly aninguinal hernia, the ultrasound technique de-scribed subsequently evaluates the anatomic loca-tion where these uncommon hernias occur. Forthis reason, these hernias will be included in thediscussion to follow.

Fig. 6. 30-year-old man with an indirect inguinal her-nia (H) extending into the medial inguinal canal. Thepubic tubercle (T), which is a landmark for the superfi-cial inguinal ring, allows assessment of the extent ofherniation at the time of examination. The transducerhas been angled to parallel the inguinal canal, andimages the medial inguinal canal. Right is medial.

Fig. 7. 35-year-old man with a right femoral hernia(H) that is deforming the posterior–medial wall(straight arrows) of the femoral vein (V). The trans-ducer is in the axial plane caudad to the inguinal lig-ament. Curved arrows 5 superior pubic ramus. Rightis medial.

Jamadar & Franz714

Ultrasound technique—general

The patient is exposed to uncover the inguinal re-gion, which usually necessitates the removal of un-dergarments. Helpful visual landmarks for initialorientation before scanning are the umbilicus, theanterior superior iliac spine, the pubis, and theproximal thigh. The operator sits comfortably nextto the supine patient and initially scans in the axialplane. Because of the small field of view of thetransducer, scanning is done incrementally, withliberal use of the Valsalva maneuver [15]. The Val-salva maneuver may be employed as many as 50to 60 times to evaluate the inguinal region. If neces-sary, the patient may be scanned in the upright

Fig. 8. 41-year-old woman with a left spigelian herniaconsisting of bowel (B) and extraperitoneal fat (EF)passing through the linea semilunaris between therectus abdominis muscle (R) and the flank muscles(F). Superficially, the hernia dissects deep to the fasciaof the external oblique muscle (curved arrows),explaining the clinically occult Spigelian hernia withinterplane dissection. The scan is in the axial plane.

position, or asked to perform a particular maneuverthat precipitates the hernia.

The authors have found an intermittent increasein intra-abdominal pressure (the Valsalva maneu-ver) a critical component of the sonographicexamination. During the Valsalva maneuver, themovement of herniating contents helps identifythe presence of a hernia, particularly the small fattyhernias with no bowel or fluid content. Withoutthis movement, these small fat-containing herniasmay be indistinguishable from the adjacent adiposetissue, and it is only by their movement that thepresence of a hernia may be appreciated. The direc-tion of movement relative to the transducer duringthe Valsalva maneuver helps in the identification ofa particular type of hernia as a direct inguinal, an in-direct inguinal, and a femoral hernia each move ina particular direction relative to the transducer attheir neck. The ultrasound appearance of the herniamay vary depending on the contents; herniatedbowel may show peristalsis, while herniated fatwill appear hyperechoic.

Usually, movement of a hernia is appreciated bestduring the positive-pressure phase of the Valsalvamaneuver. The temptation is to scan over the areaof interest during the positive-pressure phase ofthe Valsalva maneuver, then to move the transducerfor another incremental evaluation during the re-laxation phase. Occasionally, a hernia may be ap-preciated better during the relaxation phase of theValsalva maneuver, where herniated tissue may beseen returning to the abdominal cavity throughthe hernia neck. The author’s practice is that eachincremental area of evaluation be observed duringthe entire cycle of the Valsalva maneuver.

As inguinal region hernias occur through the an-terior abdominal wall, a 9 MHz or higher frequencytransducer may be used for most patients except themarkedly obese. A history of prior hernia surgerywith or without the use of mesh for surgical repairis helpful. Obesity and multiple gestations may re-sult in laxity of the structures of the inguinal region,and adjacent surgical scars may distort the anatomy,all of which will have to be taken into account dur-ing the sonographic examination.

A hernia may not be identified, even though thepatient complains of inguinal pain or discomfort.In these cases, surgical colleagues appreciate a com-ment on the absence of a hernia while scanningover the area of discomfort. Of course, a report ofany unexpected abnormality that ultrasound maydetect is often useful clinical information.

Ultrasound technique—specific

With the inguinal area exposed, the lateral border ofthe rectus abdominis muscle inferior to the


umbilicus is identified in the axial plane. By scan-ning along the lateral border of the rectus abdomi-nis muscle, the inferior epigastric artery can beidentified as it passes under the rectus abdominismuscle (see Fig. 2). Just above the point where theinferior epigastric artery passes under the lateral bor-der of the rectus abdominis muscle is a weak pointin the structure of the anterior abdominal wall andwhere the Spigelian hernia occurs. This weaknessoccurs where the rectus sheath transitions fromcompletely encircling the rectus abdominis muscle(above the arcuate line) to only covering the super-ficial (anterior) surface of the rectus abdominismuscle (below the Arcuate line). The neck of the Spi-gelian hernia occurs between the lateral border ofthe rectus abdominis muscle and the flank muscles(the linea semilunaris). By evaluating this area andusing the Valsalva maneuver, a Spigelian herniamay be identified. At its neck, a Spigelian herniamoves directly toward the ultrasound transduceras it passes through the linea semilunaris.

The inferior epigastric artery can be traced in theaxial plane from cranial to caudad, starting where itpasses deep to the rectus abdominis muscle to itsorigin from the external iliac artery, defining the lat-eral border of Hesselbach’s triangle. Just caudad tothe origin of the inferior epigastric artery from theexternal iliac artery is the inguinal ligament, whosemedial extent is from this point to the palpable pu-bic tubercle. By rotating the transducer to lie alongthis imaginary line, the inguinal ligament may beidentified (see Figs. 1 and 3), defining the inferiorborder of Hesselbach’s triangle. The inguinal liga-ment may be identified easily in many, but not allpatients. Direct inguinal hernias commonly occurin the inferior aspect of Hesselbach’s triangle. A di-rect inguinal hernia, however, may occur anywhere

Fig. 9. 22-year old man with normal anatomy of the inguinal shows the spermatic cord (arrowheads), which appearlarity, lying superficial to the inferior epigastric artery (E) ashort axis. Note spermatic cord is identified lateral to infscan along the inferior epigastric artery (E) shows theA, external iliac artery.

in Hesselbach’s triangle, and the entire area of thetriangle should be interrogated incrementally usingthe Valsalva maneuver. A direct inguinal hernia usu-ally has a wide somewhat ill-defined neck, and thechallenge is to differentiate a bulge of the anteriorabdominal wall from a direct hernia. As a guideto making the diagnosis of a small direct hernia,the authors use the inferior epigastric artery as ananatomic landmark (see Fig. 4). If movement ofthe tissue extends superficial (anterior) to the infe-rior epigastric artery, then this is a direct hernia. Ifmovement of the tissue does not extend superficial(anterior) to the inferior epigastric artery (ie, the an-terior abdominal wall moves as a unit), then a directhernia does not exist. A hernia whose neck lies inHesselbach’s triangle is a direct inguinal hernia,and movement of these hernias at their neck is di-rectly toward the ultrasound transducer.

Sonographically, the inguinal canal lies just cra-nial and parallel to the inguinal ligament, and thedeep inguinal ring lies lateral to the inferior epigas-tric artery (see Fig. 1). The inguinal canal containsthe round ligament in females and spermatic cordin males (Fig. 9). An indirect inguinal hernia hasits neck at the deep inguinal ring, which is just cra-nial to the inguinal ligament and just lateral to theinferior epigastric artery. By angling the transduceralong the inguinal canal, which is just cranial andparallels the inguinal ligament, the movement ofthe hernia through the deep inguinal ring and sub-sequent passage along the inguinal canal and ulti-mately out through the superficial inguinal ringmay be demonstrated. The movement of the indi-rect inguinal hernia is somewhat complex. At thedeep ring, lateral to the inferior epigastric artery,movement is initially toward the transducer. Then,a change in direction of movement of the hernia

nal region. (A) Ultrasound scan along the inguinal ca-s heterogeneous with hypoechoic tubules and vascu-nd external iliac artery (A). Scan shows the arteries in

erior epigastric artery. Right is medial. (B) Ultrasoundspermatic cord in short axis (arrows). Abbreviation:

Fig. 10. 29-year-old woman with a surgically reducedleft femoral hernia, seen from within the abdomen,which was not detected with sonography. Intraoper-ative photograph shows the approximate position ofthe nonvisualized medial inguinal ligament (blackline), the inferior epigastric artery (straight whitearrows), Hesselbach’s triangle (H), the external iliacvein (V), the approximate position of the obscuredexternal iliac artery (aa), the femoral canal (f), and ly-ing adjacent, the reduced fatty femoral hernia(straight black arrows). Note the medial border ofthe deep ring (curved arrow) and the forceps (*)just having manipulated fat (also known as a lipomaof the cord [L]) from the inguinal canal through thedeep inguinal ring.

Jamadar & Franz716

contents occurs, now across the plane of the trans-ducer (see Fig. 6), as the herniating contents passalong the inguinal canal. Finally, at the superficialring, movement is once again toward the trans-ducer, after which the hernia may pass into the scro-tum in males. Of course, not all indirect inguinalhernias extend through the superficial ring, and of-ten, the initial movement at the deep ring may notbe appreciated easily.

Caudad to the inguinal ligament and medial tothe femoral vein is the femoral canal (see Fig. 1),through which most femoral hernias occur. Thesemay be small hernias and only appreciated follow-ing a forceful Valsalva maneuver. Movement hereparallels the long axis of the femoral vein (whichnormally dilates during Valsalva) and is across theplane of the transducer. When scanning in the axialplane, the hernia contents usually appear medial tothe femoral vein expanding the femoral canal, andmay deform the femoral vein along its medial wall(see Fig. 7). The presence of pain in the femoralarea, even in the absence of a hernia, is useful infor-mation for the referring surgeon.

Pitfalls

The absence of movement

The authors rely on identifying movement of her-nias when intra-abdominal pressure is increasedto make a confident diagnosis of a hernia. This is es-pecially important when the hernia is small or isa fatty hernia without a bowel component. The ab-sence of movement may occur when the herniatedcontents do not move, or the patient is not ableto perform an adequate Valsalva maneuver. In thesesituations, the hernia may not be appreciated(Fig. 10). This is most important with the femoralhernia, which if small, may be a difficult clinical di-agnosis to make. With herniated bowel, reliance onthe presence of fluid around the hernia, a change inechogenicity of the herniated fat and possibly hy-peremia of adjacent edematous tissues may pointto a diagnosis.

Movement of the spermatic cord

The normal spermatic cord has been observed tomove about 0.5 cm in the inguinal canal duringa Valsalva maneuver (see Fig. 9). This movementmay be confused with the movement of an indirectinguinal hernia. Usually, the indirect inguinal her-nia in addition to moving along the inguinal canaltends to distend the canal, resulting in a discernablechange in volume of the inguinal canal. In this sit-uation, additional scanning along the short axis ofthe inguinal canal may show a hernia filling anddistending in addition to moving along the ingui-nal canal. In contrast, the spermatic cord moves

normally along the inguinal canal with no appre-ciable change in volume of the canal.

Movement of the normal intra-abdominalcontents

This pitfall usually occurs in thin patients. In the su-pine position, in the inguinal region, the anteriorabdominal wall may come in contact with theposterior abdominal wall. No intra-abdominalcontents separate the anterior and posterior ab-dominal walls, as the intra-abdominal contentshave moved away from under the inguinal regionand are lying adjacent. With an increase in intra-ab-dominal pressure, these contents are distributedmore evenly throughout the abdominal cavity andmove into the inguinal region. This normal move-ment of intra-abdominal contents may be misinter-preted as movement along the inguinal canal, as itis perceived as movement parallel to the plane ofthe transducer. An indirect inguinal hernia may bediagnosed in error. This error of interpretation iscompounded by the small field of view of the trans-ducer, the limited depth of view with the higher fre-quency transducer, and the difficulty in defining thesoft tissue planes while scanning from superficial todeep in the inguinal region (Fig. 11A, B). This canbe resolved easily by asking the patient to maintain

Fig. 11. 49-year-old woman with normal intra-abdominal content movement. In the supine position, the ante-rior and posterior abdominal wall parietal peritoneum may be difficult to identify. A sagittal scan in the inguinalregion shows: (A) the anterior and posterior abdominal walls are in contact with no intervening intra-abdominalcontents. The arrows show the peritoneum separated by a sliver of physiologic intraperitoneal fluid. (B) Duringa Valsalva maneuver, the parietal peritoneum (arrows) is separated by intra-abdominal content, in this casebowel (B) as increasing pressure redistributes intra-abdominal contents into the inguinal region.


positive pressure while scanning cranially to dem-onstrate continuity with the intra-abdominal con-tents. The pitfall lies in not recognizing that thisscenario may exist.

Iliopsoas movement

In the supine position, the patient may flex the hipas part of his or her attempt to increase intra-ab-dominal pressure. The contraction of the iliopsoasmuscle may produce movement that may be inter-preted as movement toward the transducer simulat-ing a small inguinal hernia. This usually occurs invery thin patients or very muscular patients, wherethe iliopsoas muscle is relatively bulky and promi-nent at sonography.

Direct inguinal hernia simulating an indirectinguinal hernia

Infrequently, a direct inguinal hernia may show ex-pected movement toward the transducer, thenmove unexpectedly through the tissue planes paral-lel to the face of the transducer. The combination ofdirection of movement of the hernia if approxi-mately along the direction of the inguinal canalmay resemble an indirect inguinal hernia superfi-cially. Of course, identifying the neck of the herniaas medial to the inferior epigastric artery and cranialto the inguinal ligament would clarify the diagnosisof a direct inguinal hernia.

Pitfalls from sonographic technique

Excessive pressure with the transducer over the in-guinal region may mask the presence of a reduciblehernia. Failure to methodically evaluate the entirearea of Hesselbach’s triangle, or the entire margin

of a mesh implant used to repair an inguinal herniawhile using the Valsalva maneuver may result inmissing a direct inguinal or recurrent hernia.

The femoral vein typically dilates during the pos-itive-pressure phase of the Valsalva maneuver, andthis is a normal finding that should not be misinter-preted as a femoral hernia.

The narrow field of view of the transducer occa-sionally may make differentiating the normalmovement of the abdominal wall from a herniachallenging. This is especially true for the Spigelianhernia, particularly in the well-muscled patient,where normal movement between the bulky rectusabdominis and flank muscles may be toward thetransducer. By scanning the adjacent anterior ab-dominal wall, a more global impression of tissuemovement will help to differentiate between a her-nia and normal movement. Normal movement willnot result in extraperitoneal fat or bowel passinganteriorly through the linea semilunaris, which iswhere the neck of a Spigelian hernia is located.

Complications

Inguinal hernias may present with discomfort inthe groin, or may present as a transient mass thatis aesthetically displeasing. Significant morbidityand mortality from hernias [8,16], however, usuallyare related to an intra-abdominal viscus that hasherniated, and has had its blood supply obstructed,resulting in vascular compromise of the viscus. Inthe inguinal region, although bowel is the mostcommon intra-abdominal viscus to herniate, otherintra-abdominal organs have herniated through aninguinal hernia including the ovary, the bladder

Fig. 12. 52-year-old woman with an irreducible right femoral hernia. The scan is in the sagittal plane over thefemoral canal. (A) The bowel wall (curved arrows) and neck (N) of the hernia are well-demonstrated, as isboth intraluminal fluid (IF) and fluid in the femoral canal distal to the hernia (EF). (B) The application of powerDoppler shows blood flow, which supports viable bowel in this case, information that is important for the clin-ical management of the patient. Bowel wall 5 curved arrows.

Fig. 13. 36-year-old woman presented with enlargingand painful right irreducible femoral hernia (H), con-sisting of extraperitoneal fat. The scan is in the sagit-tal plane over the femoral canal. Fluid (F) distal to thehernia and the neck (N) of the hernia were well-dem-onstrated. There was no increased flow with powerDoppler imaging.

Jamadar & Franz718

wall, and the vermiform appendix [17–20]. An in-carcerated or irreducible hernia is one where thecontents of the hernia cannot be returned to theirnormal intra-abdominal position (Fig. 12A, B).An obstructed hernia is a hernia of bowel wherethere is intestinal obstruction at the hernia, butthe bowel itself remains viable. A strangulated her-nia is one where the blood supply to the herniatedloop of bowel is compromised, resulting in ische-mia and ultimately necrosis. The femoral herniawith its small neck and relatively rigid walls of thefemoral canal most often undergoes these compli-cations, while the direct inguinal hernia, with itswide neck, undergoes these complications least of-ten. The irreducible hernia may show bowel wallthickening, free fluid within the hernial sac, andfluid within herniated bowel loops. As the herni-ated bowel becomes necrotic, the absence of bowelperistalsis and the absence of blood flow within thehernia may be noted. Gas in the bowel wall or freeintraperitoneal or hernial sac gas suggests necroticbowel [21]. If the hernia consists only of fat, freefluid within the hernial sac may be the only sono-graphic sign of an irreducible hernia (Fig. 13).

The incisional hernia

An incisional hernia is a hernia that occurs at thesite of a surgical incision, such as a laparotomyscar. In the inguinal region, it is important to differ-entiate between an incisional hernia of the lowerabdominal wall and an inguinal hernia, as the sur-gical approaches for repair may be different for thetwo [22]. In the right inguinal region, an appendec-tomy scar incisional hernia may be confused with

an indirect inguinal hernia, and careful surgical his-tory taking is important. The incisional herniademonstrates movement toward the transducer atthe neck of the hernia with the Valsalva maneuver.

Clinical diagnostic dilemmas

Not infrequently, a patient presents with a clinicaldiagnosis of an inguinal hernia, and another diag-nosis is found. Sonography is very useful in differ-entiating these different diagnoses, which maypresent as an inguinal hernia. In general, groinswellings or masses that may increase and decreasein size include hernia, lymphadenopathy, hydro-celes, spermatoceles, and hemangioma (Fig. 14).

Fig. 14. 63-year-old woman with a left adductor longus hemangioma presented for sonography to rule out aninguinal hernia. The scans are over the adductor origin. Both sides are shown, with the symptomatic left sideshowing swelling and abnormal sonographic appearance of the adductor longus muscle – heterogenously echo-genic with branching linear hypoechogenic vascular channels (arrows) within. Note normal sonographic appear-ances of muscle on the right side. Abbreviations: Long, adductor longus; Brev, adductor brevis.

Fig. 16. 53-year-old woman with a varix of the leftsaphenous vein. The scan is over the proximal longsaphenous vein showing a focal variceal dilatation(V) of the saphenous vein (vv) just before it joinsthe femoral vein (F).


The clinical history may point to a hernia, andparticularly with an ill-defined small mass on clin-ical examination, ultrasound may be able to clarifythe pathology. Inguinal lymph nodes (Fig. 15) orother masses occasionally may be difficult to differ-entiate from an inguinal hernia clinically as may ve-nous varices (Figs. 16–18) and pseudo aneurysms[23–25]. A hydrocele or a cyst of the spermaticcord (Fig. 19) also occasionally may be clinicallyproblematic. Inflammation of the spermatic cordmay present as an inguinal hernia, where becauseof the inflammatory changes, a diagnosis of ische-mia or necrosis of hernial contents may beentertained.

Repair of inguinal hernias

Synthetic patches used in the repair of abdominalwall hernias first were described in 1962 [26], andtoday, these synthetic mesh products have been

Fig. 15. 25-year-old woman with right inguinal lymphnodes. The scan is below and parallel to the inguinalligament showing a lymph node (arrows) with anechogenic hilum (H). (A) Femoral artery; (V) femoralvein. Right is medial.

Fig. 17. 42-year-old man with a left variocele. Thescan is over the pubic tubercle (T). Note extensiveflow in distended veins that accompany the spermaticcord.

Fig. 18. 68-year-old woman with a left varicocele of the round ligament presenting as an inguinal hernia. Theultrasound scan is parallel to the inguinal ligament. (A) Increased flow in dilated veins along the inguinal liga-ment is demonstrated by ultrasound. (B) A CT scan shows corresponding left inguinal mass (arrow) diagnosedclinically as a hernia.

Jamadar & Franz720

shown to be superior to simple suture of the herniadefect [27–29]. Currently, most mesh for this pur-pose is made from polypropylene or polytetra-fluoroethylene [30,31] and when implanted,functions as a bridge across deficient tissue(Fig. 20). Over time, the mesh is incorporatedinto the healing tissues forming a robust supportingstructure. This healing process may cause meshshrinkage [32], which imparts a wavy contour tothe mesh (Fig. 21). For inguinal hernia repair, themesh most commonly is placed deep to the ingui-nal canal (external oblique aponeurosis) at the levelof the transversalis fascia, or in an extraperitoneallocation. This is the case during standard open in-guinal hernia repair using an anterior incision andapproach. Typically, the mesh is sewn to the edgesof the transversalis fascia and shelving edge of theinguinal ligament using synthetic sutures. Themesh is placed in the preperitoneal position, deepto the transversalis fascia and superficial to the

Fig. 19. 21-year-old man with a hydrocele of the sper-matic cord. The scan is caudad to the superficial in-guinal ring along the spermatic cord and shows thehydrocele (H) and the adjacent superior pole of thetesticle (T).

peritoneum. The mesh implant usually is heldagainst the anterior abdominal wall by metallictacks, or tissue glue [33], the former sometimes vi-sualized during an ultrasound examination(Fig. 22). The mesh plug (Figs. 23 and 24), whichis folded to form a plug, functions by physically oc-cupying space, which when placed in the neck ofa hernia, prevents herniation from occurring by ob-structing the free passage of a potential hernia at itsneck. Mesh plugs typically are used for the repair ofdirect inguinal or indirect inguinal hernias.

Sonographically, implanted mesh appears asa linear echoic structure with posterior acousticshadowing [34]. Not infrequently, the mesh maybe difficult to appreciate. In this situation, by in-creasing the field of view (depth), one may appreci-ate acoustic shadowing more easily and be moreconfident of identifying mesh. Although in vitrostructures may be appreciated deep to the mesh,with incorporation into the tissues, the mesh actsas a reflector of sound, with resultant acoustic shad-owing and resultant obscuration of deeper tissues.The authors have observed in a small number ofcases of abscess, formation around anterior abdom-inal wall mesh, where the mesh may be seen asa separate structure (Fig. 25).

Complications of mesh repair for inguinal hernia[34–36] include failure of the repair with recurrenthernia usually at the mesh abdominal wall inter-face, migration of an implant, and complicationsassociated with a foreign body. Failure of incorpora-tion of the mesh into the soft tissues results in weakpoints through which a recurrent hernia may occur,typically seen at the margins of the mesh (Fig. 26).Seromas and hematomas may occur adjacent toimplanted mesh, either of which may become in-fected. The mesh may become somewhat rigid,and deform adjacent soft tissue structures(Fig. 27). Displacement or migration of the mesh

Fig. 20. Photograph and in vitro sonogram of meshused for inguinal hernia repair. (A) Photograph showsa linear defect (straight arrows) and contiguousround defect (C) that allows placement of monofila-ment polypropylene mesh (Bard, Cranston, Rhode Is-land) around the spermatic cord and providessupport for the inguinal wall. A spiral metallic tack(curved arrow) (Protac, Tyco, Norwalk, CT), sometimesused for securing the mesh to the adjacent tissues, isshown. Metallic anchors are especially commonfollowing laparoscopic inguinal hernia repair. (B) Invitro sonogram shows mesh (straight arrows) witha metallic tack (curved arrow) in place. Note the distalphalanx (dp) and middle phalanx (mp) of a fingerdeep to the mesh.

Fig. 21. 31-year-old woman with mesh repair of an in-guinal hernia. The mesh (arrows) is wavy in configu-ration because of incorporation into the deeper softtissues. There is the expected posterior acoustic shad-owing (S) that obscures detail.

Fig. 22. 29-year-old man with laparoscopic repair ofan inguinal hernia showing the polypropylene mesh(arrow heads) and the tacks (arrows) used to securethe mesh to the adjacent soft tissues.


plug may occur, with resultant recurrent herniationor serious complications as bowel perforation.

Sonographic evaluation followingmesh repair

The basic principles apply, and the anatomy isunchanged except for the presence of mesh. Themesh as it becomes incorporated into the soft tissuesof the inguinal region produces acoustic shadowing,so any abnormality deep to the mesh will not be

imaged. Adhesions between the bowel and the peri-toneum deep to the mesh will not be appreciated.

The entire margin of the mesh should be imagedincrementally using the Valsalva maneuver, andnote should be made of the relationship of themesh to the adjacent soft tissues such as the sper-matic cord and inferior epigastric artery. The Spige-lian and femoral areas often are visualized aroundmesh placed for direct and indirect inguinal herniarepair, and these areas should be imaged.

Fig. 23. (A, B) Monofilament polypropylene mesh plug (PerFix, Bard, Cranston, RI).

Jamadar & Franz722

Limitations of sonography

Ultrasound is operator-dependent, and an under-standing of the sonographic anatomy is essentialand is particularly important, as the field-of-viewof the transducers in use are relatively small.This keyhole perspective necessitates a thoroughunderstanding of the adjacent anatomy. In the pa-tient who is unable to perform repetitive and rea-sonably forceful Valsalva maneuvers, inguinalhernias, particularly small fat-containing hernias,may be overlooked. In the very obese patient, andin those in whom there may be distortion of thenormal anatomy, diagnosis may be difficult. Thepaucity of sonographic landmarks and the presenceof adipose tissue in and around the structures of the

Fig. 24. 41-year-old woman with mesh plug repair ofa left inguinal hernia. Note the dense posterioracoustic shadowing (S) from the mesh plug.

inguinal region make the diagnosis of small fat-con-taining hernias a challenge. The acoustic propertiesof mesh with posterior shadowing obscures detailand adhesions of bowel or any other pathologydeep to the mesh usually cannot be appreciated.

The sports hernia

Groin pain in athletic patients may be attributed toone of four broad categories [37]: adductor longusdysfunction, osteitis pubis, hip joint pathology, andthe sports hernia. The reported cause of a sportshernia varies in the literature, from an actual

Fig. 25. 53-year-old woman with an enterocutaneousfistula and an abscess around mesh (arrows) in theanterior abdominal wall. Two layers of mesh areseen, similar to the in vitro appearances. Abbrevia-tions: O, cutaneous opening; P, echogenic phlegmon.

Fig. 26. 39-year-old woman with a recurrent inguinalhernia (H) at the inferior margin of mesh (arrowheads). The hernia protrudes more superficially thanthe mesh (arrows).


inguinal hernia [38], a dilated superficial inguinalring [39], a deficient posterior inguinal canal wall[40], the presence of a lipoma of the cord, to the ab-sence of a hernia [41]. Others believe rectus abdom-inus insertion injury at the pubis is the cause ofa sports hernia [42]. It is possible that differenttypes of athletes may have different causes forwhat is clinically described as a sports hernia. Ultra-sound has been shown to demonstrate posteriorwall deficiency of the inguinal canal as a cause ofgroin pain in Australian Rules footballers [43].

Ultrasound of hernias—a generalsurgeon’s perspective

Inguinal hernia repair is the most common proce-dure performed by general surgeons. When an in-guinal hernia presents for the first time asa symptomatic bulge, operative repair may beplanned based on physical examination alone. Ifan inguinal hernia presents incarcerated withthreatened tissue or bowel ischemia, the decisionto operate again usually is made based on physicalexamination findings.

Fig. 27. 38-year-old woman with left femoral herniarepair. The mesh (straight arrows) has impinged onthe inferior epigastric artery, which now curves atits origin from the external iliac artery (EI).

Ultrasound of the groin anatomy is especiallyhelpful when considering a recurrent inguinal her-nia repair. Unfortunately, approximately 10% of in-guinal hernia repairs are performed for recurrence.These operations are much more difficult becauseof scar tissue and distorted anatomy. More andmore often, the presence of a synthetic mesh im-plant contributes to the distorted anatomy. The ul-trasound study is dynamic and can stage allpotential weaknesses of the inguinal floor. Ultra-sound is also very useful for evaluating the femoralspace, beneath the inguinal ligament, one site ofhernia recurrence. The other common sites of recur-rence following a primary mesh repair, inferome-dial to the inferior epigastric vessels (below themesh), and lateral to the edge of the mesh, arewell-visualized during ultrasonography. Stagingthe mechanism of the recurrence and evaluatingavailable tissue components for reconstructionshould lead to improved results of recurrent ingui-nal hernia repair.

Another common but difficult scenario for thesurgeon is a patient who has groin pain but nobulge. Ultrasonography of the inguinal anatomyis especially powerful here for defining occult in-guinal defects with herniation that are not evidenton physical examination. These patients are candi-dates for operative repair. Again, the ultrasoundstudy is better than physical examination for eval-uating the femoral space and a Spigelian defect.Abnormal position of mesh or mesh migrationor shrinkage is also visible by ultrasound. Ana-tomic information regarding mesh performanceis important for evaluating the causes of groinpain. A newer entity suggested for the cause ofgroin pain without an obvious structural defecton physical examination is the sportsman’s hernia.There is not yet enough clinical experience to de-fine a sportsman’s hernia, but most simply it ischronic groin pain in athletic individuals. Infero-medial adductor tendonitis and athletic pubalgiashould be ruled out by history, physical examina-tion, and MR imaging. When an occult herniais seen on ultrasound, an operative repair isrecommended.

Finally, lower abdominal wall incisions are in-creasingly common with increased volume of Cae-sarian sections and urological procedures, forexample. Incisional hernia of the lower abdominalwall may be confused for inguinal hernias. Ultra-sound is able to define the origin of the hernianeck and distinguish incisional hernias from ingui-nal hernias. These findings are very significant inthat the anatomy, surgical approaches to repair,and biology of incisional hernias and inguinal her-nias are very different. Ultrasound again helps planthe appropriate operation.

Jamadar & Franz724

Summary

Sonography of hernias of the inguinal region isa useful and accurate imaging modality for makinga diagnosis of inguinal hernia and for identifyingcomplications that may arise following surgery inmost cases. With attention to detail, and positive re-inforcement from the surgical team, this can bea very satisfying part of a radiologist’s practice.

Acknowledgments

The authors thank Stephanie Creel, Tracy Boon,Brian Robertson, Heidi Taraskiewicz and WenzhenLiang for their contribution to understanding thesonographic evaluation of inguinal hernias.

References

[1] Papavramidou NS, Christopoulou-Aletras H.Treatment of hernia in the writings of Celsus (Firstcentury AD). World J Surg 2005;29:1343–7.

[2] Lascaratos JG, Tsiamis C, Kostakis A. Surgery foringuinal hernias in Byzantine times (A.D. 324 –1453): first scientific descriptions. World J Surg2003;27:1165–9.

[3] Rutkow IM. Surgical operations in the UnitedStates, then (1983) and now (1994). Arch Surg1997;132:983–90.

[4] Rutkow IM. Demographic and socioeconomicaspects of hernia repair in the United States in2003. Surg Clin North Am 2003;83:1045–51.

[5] Ruhl CE, Everhart JE. Risk factors for inguinalhernia among adults in the US population. AmJ Epidemiol 2007;165:1154–61.

[6] Nilsson H, Stylianidis G, Haapamaki M, et al.Mortality after groin hernia surgery. Ann Surg2007;245:656–60.

[7] McIntosh A, Hutchinson A, Roberts A, et al. Evi-dence-based management of groin hernia in pri-mary care—a systematic review. Fam Pract 2000;17:442–7.

[8] Kulah B, Duzgun AP, Moran M, et al. Emergencyhernia repairs in elderly patients. Am J Surg2001;182:455–9.

[9] Robinson P, Hensor E, Lansdown MJ, et al. Ingui-nofemoral hernia: accuracy of sonography in pa-tients with indeterminate clinical features. AJR2006;187:1168–78.

[10] Jamadar DA, Jacobson JA, Morag Y, et al. Charac-teristic locations of inguinal region hernias: so-nographic appearances and identification ofclinical pitfalls. AJR 2007;188:1356–64.

[11] Fagan SP, Awad SS. Abdominal wall anatomy: thekey to a successful inguinal hernia repair. Am JSurg 2004;188:3S–8S (Suppl to Dec 2004).

[12] Holzheimer RG. Inguinal hernia: classification, di-agnosis and treatment. Classic, traumatic, andsportsman’s hernia. Eur J Med Res 2005;10:121–34.

[13] Zhang GQ, Sugiyama M, Hagi H, et al. Groinhernias in adults: value of color Doppler

sonography in their classification. J Clin Ultra-sound 2001;29:429–34.

[14] Delabrousse E, Michalakis D, Sarlieve P, et al.Value of the pubic tubercle as a CT referencepoint in groin hernias. J Radiol 2005;86:651–4.

[15] Jaffe TA, O’Connell MJ, Harris JP, et al. MDCT ofabdominal wall hernias: is there a role for Valsal-va’s maneuver? AJR 2005;181:847–51.

[16] Askew G, Williams GT, Brown SC. Delay in pre-sentation and misdiagnosis of strangulated her-nia: prospective study. J R Coll Surg Edinb1992;37:37–8.

[17] Salemis NS, Nisotakis K, Nazos K, et al. Perforatedappendix and periappendicular abscess within aninguinal hernia. Hernia 2006;10:528–30.

[18] Manatt S, Campbell JB, Ramji F, et al. Inguinalherniation of the bladder in an infant. Can JUrol 2006;13:3057–8.

[19] George EK, Oudesluys-Murphy AM, Madern GC,et al. Inguinal hernias containing the uterus,fallopian tube, and ovary in premature femaleinfants. J Pediatr 2000;136:696–8.

[20] Verbeeck N, Niedercorn JB, McIntire D, et al. As-sessment of renal graft obstruction due to ure-teral inguinal hernia: US detection and 3D MRconfirmation. JBR-BTR 2007;90:132–4.

[21] Rettenbacher T, Hollerweger A, Macheiner P,et al. Abdominal wall hernias: cross-sectional im-aging with signs of incarceration determinedwith sonography. AJR 2001;177:1061–6.

[22] Basu S, Pandey M, Sharma CL. A hernia in theinguinal region is not always an inguinal hernia.Hernia 2007;11:449–51.

[23] Castaldo ET, Williams EH, Dattilo J, et al. Com-mon femoral vein aneurysm simulating an in-guinal hernia. Am Surg 2005;71:591–4.

[24] Majeski J. Surgical repair of primary saphenousvein aneurysm of the proximal leg after initialpresentation as an inguinal hernia. Am Surg2002;68:999–1002.

[25] Cheng D, Lam H, Lam C. Round ligament vari-ces in pregnancy mimicking inguinal hernia: anultrasound diagnosis. Ultrasound Obstet Gyne-col 1997;9:198–9.

[26] Usher FC. Hernia repair with Marlex mesh. Ananalysis of 541 cases. Ach Surg 1962;88:325–8.

[27] Burger JW, Luijendikj RW, Hop WC, et al. Long-term follow-up of a randomized controlled trialof suture versus mesh repair of incisional hernia.Ann Surg 2004;249:578–83.

[28] Stickel M, Rentsch M, Clevert DA, et al. Laparo-scopic mesh repair of incisional hernia: an alter-native to the conventional open repair? Hernia2007;11:217–22.

[29] van Veen RN, Wijsmuller AR, Vrijland WW, et al.Long-term follow-up of a randomized clinicaltrial of nonmesh versus mesh repair of primaryinguinal hernia. Br J Surg 2007;94:506–10.

[30] Novitsky YW, Harrell AG, Hope WW, et al. Meshesin hernia repair. Surg Technol Int 2007;16:123–7.

[31] Mathes SJ, Steinwald PM, Foster RD, et al.Complex abdominal wall reconstruction:


a comparison of flap and mesh closure. Ann Surg2000;232:586–94.

[32] Gonzales R, Fugate K, McClusky D, et al. Rela-tionship between tissue ingrowth and mesh con-traction. World J Surg 2005;29:1038–43.

[33] Lovisetto F, Zonta S, Rota E, et al. Use of humanfibrin glue (Tissucol) versus staples for mesh fix-ation in laparoscopic transabdominal preperito-neal hernioplasty: a prospective randomizedstudy. Ann Surg 2007;245:222–31.

[34] Crespi G, Giannetta E, Mariani F, et al. Imagingof early postoperative complications after poly-propylene mesh repair of inguinal hernia. RadiolMed (Torino) 2004;108:107–15.

[35] Stout CL, Foret A, Christie DB, et al. Small bowelvolvulus caused by migrating mesh plug. AmSurg 2007;73:796–7.

[36] Murphy JW, Misra DC, Silverglide B. Sigmoidcolonic fistula secondary to Perfix-plug, left in-guinal hernia repair. Hernia 2006;10:436–8.

[37] Schilders E, Bismil Q, Robinson P, et al. Adduc-tor-related groin pain in competitive athletes.Role of adductor enthesis, magnetic resonance

imaging, and entheseal pubic cleft injections. JBone Joint Surg Am 2007;89:2173–8.

[38] van Veen RN, de Baat P, Heijboer MP, et al.Successful endoscopic treatment of chronicgroin pain in athletes. Surg Endosc 2007;21:189–93.

[39] Farber AJ, Wilckens JH. Sports hernia: diagnosisand therapeutic approach. J Am Acad OrthopSurg 2007;15:507–14.

[40] Swan KG Jr, Wolcott M. The athletic hernia: a sys-tematic review. Clin Orthop Relat Res 2007;455:78–87.

[41] Ahumada LA, Ashruf S, Espinosa-de-los-Monteros A, et al. Athletic pubalgia: definitionand surgical treatment. Ann Plast Surg 2005;55:393–6.

[42] Diesen DL, Pappas TN. Sports hernias. Adv Surg2007;41:177–87.

[43] Orchard JW, Read JW, Neophyton J, et al. Groinpain associated with ultrasound finding of ingui-nal canal posterior wall deficiency in AustralianRules footballers. Br J Sports Med 1998;32:134–9.



727

Rheumatoid Arthritis: UltrasoundAssessment of Synovitisand ErosionsRobert Lopez-Ben, MD

- Technique- Synovitis

- Erosions- References

Rheumatoid arthritis (RA) is a chronic autoim-mune disease commonly encountered in clinicalpractice. Its prevalence is estimated at approxi-mately 1% of the general population, and it pre-dominantly affects middle-aged women [1]. Thedisease is usually progressive, especially during thefirst 3 years after onset [2]. Chronic joint inflamma-tion may progress to fixed joint deformities, af-fecting activities of daily living and leading tosignificant disabilities. Recent data show that earlytreatment with anti-inflammatory and disease-modifying antirheumatic drugs (DMARDs) maydecrease the extent of joint damage and improvefunctional outcome [3]. Some of these neweragents, like tumor-necrosis factor alpha inhibitors,are expensive and are associated with significantside effects; therefore, early, accurate diagnosis isessential for good clinical practice.

The diagnosis of RA remains predominantlya clinical one. The 1987 criteria for the classificationof acute arthritis as RA, as defined by the AmericanCollege of Rheumatology, include the presence offour or more of the following [4]:

� Morning stiffness for more than 1 hour mostmornings, for at least 6 weeks

� Joint pain and soft tissue swelling of morethan 3 of 14 joints or joint groups

Department of Radiology, University of Alabama at BirmSouth, Birmingham, Alabama 35249-6830, USAE-mail address: [email protected]


� Arthritis of hand joints (wrist, metacarpo-phalangeal [MCP], and proximal interpha-langeal [PIP] joints)

� Symmetric or bilateral involvement ofarthritis

� Rheumatoid nodules

� Rheumatoid factor

� Radiologic changes suggestive of RA, such asjoint erosions or unequivocal periarticularbony decalcification

These criteria were intended to characterizepatients for clinical research purposes; in clinicalpractice, total adherence to these criteria shouldnot limit potentially beneficial therapeutic inter-ventions in patients presenting with possible in-flammatory arthritis. The classic presentation ofbilaterally symmetric polyarticular pain and swell-ing in a rheumatoid-type distribution in the hands,along with the presence of morning stiffness, cansuggest the diagnosis in most cases. The presenceof serologic markers of chronic inflammation andtypical radiographic findings, including joint spacenarrowing and marginal erosions, usually estab-lishes the diagnosis in clinical practice.

However, the clinical history and examinationcan often be atypical and confusing at presentationand can, at times, be confused with other types of

ingham School of Medicine, JT N360, 619 19th Street




Lopez-Ben728

pathology (Fig. 1). The determination of synovialinflammation on physical examination may be dif-ficult, or the distribution strikingly asymmetric, anddifferentiating these RA patients from those whohave other inflammatory conditions like seronega-tive spondyloarthropathies, and even noninflam-matory conditions like fibromyalgia, can lead touncertainty in the working diagnosis. Because sero-logic markers of inflammation may be nonspecific,objective evidence of the typical radiographicmarkers of RA, such as bone erosions, can be spe-cific and is sought for with diligence in these cases.

Unfortunately, radiographic changes may lagbehind the clinical course and underlying synovialinflammation, and may not be detected early inthe disease course [5], with 70% of patients havingnormal radiographs at presentation [6]. This lack ofdetection may be partly because erosions and lossof subchondral or cortical outline may only bediagnosed with confidence on a two-dimensionalimage when the radiographic beam has profiledthem in tangent [7]. Also, the radiographic signsof synovial inflammation, such as joint spacenarrowing and periarticular osteopenia, can havesignificant interobserver variability when subtle,and may develop slowly [8]. Because radiographycannot directly visualize the synovium and carti-lage, radiographic assessment of synovitis dependson secondary findings and can thus be difficult.

Cross-sectional imaging techniques like CT, MRimaging, and ultrasound (US) have traditionallybeen used to evaluate for complications of chronicinflammation in RA patients, such as tendon tears,entrapment neuropathies, or secondary joint infec-tions. Given the need for a more aggressive treat-ment plan with DMARDs in early RA disease

Fig. 1. Knuckle pads, a potential clinical mimic of synovitis.for periarticular soft tissue swelling and presumed RA. (dorsal soft tissue fullness (arrows). (B) Longitudinal ultrasoneous hypoechoic knuckle pad (arrows) with a normal undP, distal aspect of the proximal phalanx.

course to maximize the potential preservation ofjoint function, the recent clinical trend has beento use cross-sectional imaging as a diagnostic aidto evaluate the synovium directly and to assess thebone marrow and cartilage for evidence of inflam-mation and joint damage. MR imaging and UShave been shown to be more sensitive than clinicalexamination in determining synovitis [8]. They canbe used earlier in the disease course to determine,and to follow, more objective parameters of jointinflammation, such as effusions, synovitis, andmarginal erosions that can be radiographically oc-cult [9–12]. These techniques can help establishthe diagnosis of inflammatory arthritis in difficultcases, and can gauge the severity of the inflamma-tion and monitor possible response to therapeuticagents.

Although MR imaging has become the new ‘‘goldstandard’’ for assessment of synovial and tenosyno-vial inflammation because of its superb multiplanardepiction of soft tissue contrast, reproducible tech-niques, and ability to show underlying marrowedema and to quantitate better the synovial volumeand rate of enhancement, it is not without short-comings [13]. It remains expensive and is not asreadily accessible to patients in most rheumatologyclinics when compared with radiography and US, al-though deployment of smaller, dedicated, in-officemagnets in this setting is becoming more common.The limited field of view in some of these systemscan make overall assessment of multiple jointstime consuming. Small erosions in small jointssuch as the PIP joints can be difficult to distinguishfrom underlying edema because of partial volumeaveraging, even with high-field systems, withoutadvanced techniques like microscopy coils [14].

A 45-year-old woman referred to rheumatology clinicA) Lateral radiograph of the right ring finger showsund of the dorsal soft tissue fullness shows a subcuta-erlying PIP joint. MP, base middle phalanx ring finger;

Rheumatoid Arthritis 729

US is a safe, portable, more readily available, andless expensive alternative imaging modality to eval-uate synovitis and joint erosions. It can be per-formed readily while the patient is in clinic, withassessment of multiple joints allowing for immedi-ate diagnostic information. The usual limitations ofUS include operator dependence on technique andlimited visualization of certain joints with complexbony anatomy, like the wrist [7]. US is also effectivefor interventional guidance for joint and tendonsheath aspirations or injections, and for dynamicassessment of tendon subluxations. Although tech-niques can be variable and are not standardizedamong different practitioners, the use of US inthe early diagnosis and monitoring of therapy re-sponse in RA patients is becoming increasingly val-idated. This article focuses on the role of US inevaluating synovitis and bone erosions as outcomemeasures in the diagnosis and management ofthese patients.

Technique

US examinations of the hand and wrist joints areusually performed with high-frequency (7 MHz ormore) linear transducers with small footprints.Usually, the palmar and dorsal aspects of the MCPjoints are imaged, as well as the wrists in longitudi-nal and transverse planes. The lateral aspects of theindex and little finger MCP joints and the wrists arealso imaged. Some investigators will also image ei-ther all or selected PIP joints that are symptomaticand the metatarsophalangeal (MTP) joints of thefeet. To expedite the examination, some investiga-tors select the second and fifth MCP, the wrists,and the fifth MTP as target joints to image, giventheir high likelihood of involvement in RA andthe increased visualization of a greater portion ofthe joint on the transducer [12].

Power Doppler interrogation is usually used toassess synovial vascularity. When using power

Fig. 2. Metacarpophalangeal (MCP) joints synovitis. Effect44-year-old man with RA. (A) Longitudinal US image witshows marked synovitis (arrowheads), but (B) same areathe previous intra-articular areas of Doppler signal. Arfrom large erosion. M, metacarpal head; P, proximal phal

Doppler, it is important to minimize transducerpressure on the joint because the signal from thesmall synovial vessels can be obliterated if one isnot careful in this regard (Fig. 2). Certain artifacts,such as motion/flash and edge artifact, are commonwith power Doppler and should not be confusedwith true increased synovial blood flow [8]. TheDoppler gain setting should be set at just abovethe level of noise to increase sensitivity, but no signalshould be arising within normal cortical bone [15].

Synovitis

The inciting agent or factors responsible for trigger-ing the inflammatory mechanisms cascade in RA re-mains unknown. However, it is felt that cytokinessuch as tumor necrosis factor-alpha (TNF-alpha)and interleukin-1 are important early in the diseasecourse in facilitating recruitment of inflammatoryresponse cells that lead to synovial inflammationand edema and secondary pannus proliferation[16]. This observation has led to the current usein clinical practice of TNF-alpha inhibitors in earlyRA [17,18].

Several studies have shown that US is much moresensitive than clinical examination for the detectionof synovitis (Fig. 3) [19,20]. In one study of earlyarthritis originally felt to be oligoarthritis, USdetected subclinical synovitis in other joints intwo thirds of the patients [21]. The role of US inrheumatic disease classification could thus be animportant part of clinical practice [22].

The joints affected with RA have increased syno-vial vascularity and volume correlating with diseaseactivity [23]. Increased capillary leakage from thissynovial angiogenesis may lead to joint effusions.Effusions are sensitive but not specific for RA activ-ity [8].

A commonly used definition of synovitis on US isthat of thickened, hypoechoic, intra-articular tissuethat is poorly compressible on gray-scale B-mode

of transducer pressure on power Doppler imaging. Ah power Doppler of the right index finger MCP jointwith increased transducer pressure shows absence ofrow shows increased through transmission artifactanx.

Fig. 3. Metacarpophalangeal (MCP) joints with synovitis on gray-scale imaging. This 32-year-old man with RAwas initially felt to have oligoarthritis of the right long finger MCP joint on initial clinical presentation. (A) Lon-gitudinal US image of the right long finger MCP joint shows a distended dorsal capsular recess (arrowheads)with hypoechoic material that was not compressible, confirming synovitis. (B) A longitudinal US image of theleft index finger MCP shows similar findings of synovitis, helping to establish the polyarticular distribution inthis patient. M, metacarpal head.

Lopez-Ben730

imaging and can demonstrate increased Dopplersignals with color or power Doppler interrogation[24]. These techniques are helpful in distinguishingsynovial proliferation from joint effusion (Figs. 4–7). In particular, power Doppler is an effective toolfor measuring synovitis, with accuracy comparableto dynamic contrast-enhanced MR imaging[25,26]. Power Doppler is more sensitive than colorDoppler in assessing blood flow within small ves-sels [27]. It has also been directly correlated withhistopathology showing increased synovial bloodvessel density in the tissue of patients who haveRA when compared with the tissue of those whohave osteoarthritis, although these studies were inlarger joints [28,29]. Several studies seem to indi-cate that power Doppler changes can correlatewith treatment response (Fig. 8) [30,31].

Given the potential discrepancies in powerDoppler among different machines or operator set-tings, this technique may have significant variability

Fig. 4. Metacarpophalangeal (MCP) joint synovitis on powpatient as in Fig. 2). (A) Longitudinal US image of the righsignal (grade 3 of 3) within the distended synovial capsulewithin infiltrating pannus (arrow). (B) Longitudinal US imsynovial Doppler signal correlating with synovial hyperem

when following patients longitudinally. Methodshave been proposed to quantitate synovial bloodflow better with computer-aided region-of-interestpixel determination on power Doppler images orby using spectral resistive indices determination[26,32].

However, these methods may be too cumber-some for routine clinical practice. More commonly,a semiquantitative grading of synovial powerDoppler signal is used to assess the extent of syno-vitis. In one such grading system, 1 5 single vesseldemonstrated, 2 5 confluent vessels, and 3 5more than 50% of the imaged synovial tissue hasvisualized vessels [33]. Others add a grade 0 whenincreased hypoechoic synovium is present withoutan intra-articular power Doppler signal [19]. Inter-observer agreement with these types of semiquanti-tative assessments of synovitis has been shown tobe moderately good when studied with kappa cor-relations [34,35].

er Doppler imaging. A 32-year-old man with RA (samet long finger MCP joint shows marked power Doppler(arrowheads). Note small erosion with Doppler signalage of the left index finger MCP also shows markedia. M, metacarpal head.

Fig. 5. Proximal interphalangeal (PIP) joints synovitis in two patients. (A) A 49-year-old woman with RA andswelling of the PIP joints of the hands. Longitudinal US image lateral aspect of the right index finger PIP jointshows a minimally distended joint capsule (arrowheads). (B) Power Doppler image of the same joint showsgrade 1 of 3 intra-articular synovial signals (arrow). (C) A 70-year-old woman with new-onset RA. Gray-scale lon-gitudinal image radial aspect of the left long finger PIP joint shows a markedly distended joint capsule (arrow-heads) and possible small erosions (arrows). (D) Power Doppler image of the same joint shows grade 21 synovialhyperemia. MP, middle phalanx; P, proximal phalanx.


US contrast agents have been shown to increasepower Doppler sensitivity for synovial vascularity[36,37]. Their use may also help differentiate activesynovitis by measuring the thickness of vascularizedsynovial tissue on gray-scale imaging [38]. How-ever, their use has not yet been embraced in routineclinical practice in the United States, perhaps be-cause of problems with the routine availability ofthese contrast agents in most departments, possibleadverse effects, continued clinical trials, and the ex-tra cost and time to perform the examinations.

Fig. 6. Wrist synovitis: intra-articular. (A) A 45-year-oldimage of dorsal right wrist shows some noncompressible hcapsule (arrowheads). (B) Power Doppler image of the saitate; L, lunate; R, radius dorsal borders.

Erosions

Although somewhat controversial, the develop-ment of bone erosions within the natural historyof RA is felt to be secondary to prior synovial in-flammation and the effects of collagenase producedat the interface of the synovial pannus and cartilage[39]. Detection of marginal erosions (located at theperiphery of a synovial joint not covered by hyalinecartilage) is important for the diagnosis of RA,and prevalence early in the disease when seen

woman with new-onset RA. Gray-scale longitudinalypoechogenicity, likely representing a distended jointme joint shows grade 31 synovial hyperemia. C, cap-

Fig. 7. Wrist synovitis: extra-articular. (A) A 47-year-old woman presenting with wrist nodules on physical examina-tion and with new-onset RA. Gray-scale longitudinal image ulnar aspect right wrist shows some diffuse hypoechoicthickening surrounding the extensor carpi ulnaris (ECU) tendon consistent with tenosynovitis (arrowheads). (B)Power Doppler image of the same area shows grade 3 tenosynovial hyperemia. T, triquetrum; U, ulnar styloid.

Lopez-Ben732

radiographically is predictive of aggressive diseasecourse [40]. Radiographically, erosions developduring the first 2 years of disease onset [39]. How-ever, MR imaging and US have shown a higherprevalence of erosive disease in RA patients whencompared with radiography earlier in the diseasecourse (Fig. 9) [41,42]. The long-term prognosticimplications for erosions only seen with MR imag-ing or US have not been completely validated (espe-cially for US), but recent MR imaging studies appearto show that early erosive disease established by thismodality also predicts more aggressive diseasecourse [43].

Erosions can be diagnosed on US when a discon-tinuity of the smooth echogenic bone surface orcortex is visualized in two perpendicular planes[24]. They typically have an irregular floor andmay have increased through transmission if hypoe-choic pannus is infiltrating. Sometimes, interroga-tion with power Doppler will show increasedsignal within this pannus (Fig. 10). In some studies,2 mm in diameter is used as a minimal size cutoff incortical disruption to confidently diagnose boneerosions by US [42,44]. In a recent prospective

Fig. 8. Metacarpophalangeal (MCP) joints synovitis: effecyear-old woman with RA, on DMARDs for 2 years. US reqUS image with power Doppler of the left index finger MC(arrowheads) but (B) same area shows absence of Dopplemarkedly positive with Doppler signal. This finding may reM, metacarpal head; P, proximal phalanx.

study, almost all erosions that measured at least2 mm at baseline were detected on 6-month follow-up at the same site, whereas smaller bone irregular-ities were less constant on follow-up [45]. Anotherreason to use a size cutoff would be to distinguisherosions from normal findings such as dorsal meta-carpal head depressions (Fig. 11), which are usuallyless than 2 mm in depth and have a smooth floor.They have been identified in 37% of normal volun-teers, most prominently in the second MCP joint[46]. Unfortunately, data remain scarce on the USappearance of other normal joint structures oranatomic variants that could lead to potential inter-pretation pitfalls [35].

In several studies, US has been shown to detecterosions in the MCP and PIP joints of the hands,and the MTP joints of the feet, with greater sensitiv-ity than radiography [11,19,42]. In one study focus-ing on the MCP joints of the hands, sonographydetected 6.5 times more erosions and establishederosive disease in 7.5 times more patients than ra-diographs in early disease course. In patients whohad a longer disease course, the difference wasabout threefold, still significant between the US

t of treatment on power Doppler imaging. (A) A 35-uested to evaluate for ‘‘active’’ synovitis. LongitudinalP joint shows marked synovitis distending the capsuler signal. Previous US at onset of treatment had beenpresent a pannus undergoing fibrosis after treatment.

Fig. 9. Erosions in a patient with a 6-month history of RA. (A) Magnified view of an posteroanterior radiographright long finger metacarpophalangeal (MCP) joint interpreted as normal. Arrows show subtle radiolucency indorsal metacarpal head, which, in retrospect, could represent erosion seen en face. (B) Longitudinal US of thedorsal MCP joint shows the erosion as a cortical discontinuity with increased through transmission at the floor(arrow). M, metacarpal head; P, proximal phalanx.

Fig. 10. Erosion-visualization in both planes. In this RA patient, (A) the longitudinal US image of the index MCPjoint shows synovitis and a possible cortical discontinuity in the metacarpal, with a small Doppler signal withinthe infiltrating pannus (arrow). (B) The transverse image of this area better delineates the erosion (arrows). M,metacarpal head.

Fig. 11. Index finger with normal dorsal metacarpal head depression. (A) Longitudinal US image metacarpopha-langeal joint shows apparent small cortical step-off dorsal metacarpal head (arrow). (B) Transverse image showsuninterrupted cortical contour in this area (arrow). M, metacarpal head; P, proximal phalanx.


Fig. 12. A 52-year-old woman with progressive erosive disease right ring finger proximal interphalangeal jointon 6-month follow-up. Radiographs were negative. (A) Initial US shows a distended joint capsule (arrowheads)and subtle cortical irregularity (arrow). (B) Follow-up US shows marked progression in erosive changes in theproximal phalanx (arrows). MP, middle phalanx; P, proximal phalanx.

Lopez-Ben734

and radiographs [42]. In another study looking atthe MTP joints of the feet, US detected about 4 timesmore erosions in these joints than radiography[19].

When compared with MR imaging, US is at leastas sensitive, and some feel superior, in diagnosingbone erosions of the MCP and MTP joints[19,47]. Intra- and interobserver agreement for thepresence of US erosions is good, better than that re-ported for US synovitis grading [34,35]. However,as with synovitis assessment, the variability amongUS machines in the diagnosis of erosions has notbeen explored.

One of the roles of US in future clinical practicemay lie in the monitoring of disease, and perhapstreatment response, in patients who have early ag-gressive RA. In a recent prospective study of patientswho had early RA, US showed that the numberof erosions doubled within a short follow-up pe-riod (Fig. 12). At the end of a 6-month observationperiod, only 3 (14%) of 21 patients had erosive dis-ease based on radiographs, whereas US showed ero-sive disease in 12 (57%) of the 21 patients [45].Identification of patients with faster progressionmay help in selecting appropriate DMARD therapyto prevent further joint deterioration. Intensivetreatment, such as combination DMARDs with ste-roids or biologic therapies, could be beneficial inat-risk patients. Even in these patients, a reasonablecourse of action in early RA should be initial mono-therapy with a well-established therapeutic agentsuch as methotrexate. However, a close monitoringof disease activity to evaluate for progression maylead to a change in DMARD therapy and strategyif necessary [48]. Further, more long-term studiesare needed, including a cost-effectiveness analysisof the use of US in this setting [7].

References

[1] Hochberg MC. Adult and juvenile rheumatoidarthritis: current epidemiological concepts. Epi-demiol Rev 1981;3:2–44.

[2] Combe B, Dougados M, Goupille P, et al. Prog-nostic factors for radiographic damage in earlyrheumatoid arthritis: a multiparameter pros-pective study. Arthritis Rheum 2001;44(8):1736–43.

[3] Lard LR, Visser H, Speyer I, et al. Early versus de-layed treatment in patients with recent-onsetrheumatoid arthritis: comparison of two cohortswho received different treatment strategies. Am JMed 2001;111(6):446–51.

[4] Arnett FC, Edworthy SM, Bloch DA, et al. TheAmerican Rheumatism Association 1987 revisedcriteria for the classification of rheumatoid ar-thritis. Arthritis Rheum 1988;31(3):315–24.

[5] van der Heijde DM. Radiographic imaging: the‘gold standard’ for assessment of disease progres-sion in rheumatoid arthritis. Rheumatology2000;39(Suppl 1):9–16.

[6] Emery P. Rheumatoid arthritis: not yet curablewith early intensive therapy. Lancet 1997;350(9074):304–5.

[7] Hyzy MD, Slavotinek J, Smith MD. Role of ultra-sound in assessment of early rheumatoid arthritis.Australas Radiol 2007;51:120–6.

[8] Farrant JM, O’Connor PJ, Grainger AJ. Advancedimaging in rheumatoid arthritis. Part 1: synovitis.Skeletal Radiol 2007;36:269–79.

[9] Backhaus M, Burmester GR, Sandrock D, et al.Prospective two-year follow up study comparingnovel and conventional imaging procedures inpatients with arthritic finger joints. Ann RheumDis 2002;61:895–904.

[10] Peterfy CG. Magnetic resonance imaging in rheu-matoid arthritis: current status and future direc-tions. J Rheumatol 2001;28(5):1134–42.

[11] Hoving JL, Buchbinder R, Hall S, et al. A compar-ison of magnetic resonance imaging, sonographyand radiography of the hand in patients withearly rheumatoid arthritis. J Rheumatol 2004;31:663–75.

[12] Lopez-Ben R, Bernreuter WK, Moreland LW, et al.Ultrasound detection of bone erosions in rheu-matoid arthritis: a comparison to routine radio-graphs of the hands and feet. Skeletal Radiol2004;33:80–4.

[13] Tehranzadeh J, Ashikyan O, Dascalos J. Ad-vanced imaging of rheumatoid arthritis. RadiolClin North Am 2004;42:89–107.


[14] McQueen FM, Lassere M, Edmonds J, et al.OMERACT rheumatoid arthritis magnetic reso-nance imaging studies. Summary of OMERACT6MR imaging module. J Rheumatol 2003;30:1387–92.

[15] Rubin JM. Musculoskeletal power Doppler. EurRadiol 1999;9(Suppl 3):S403–6.

[16] Arend WP, Dayer JM. Inhibition of the produc-tion and effects of interleukin-1 and tumornecrosis factor alpha in rheumatoid arthritis.Arthritis Rheum 1995;38:151–60.

[17] Klareskog L, Van der Heijde D, De Jager JP, et al.Therapeutic effect of the combination of etaner-cept and methotrexate compared with eachtreatment alone in patients with rheumatoidarthritis: double-blind randomized controlledtrial. Lancet 2004;363:675–81.

[18] Maini RN, Breedveld FC, Kalder JR, et al. Sus-tained improvement over two years in physicalfunction, structural damage, and signs andsymptoms among patients with rheumatoid ar-thritis treated with infliximab and methotrexate.Arthritis Rheum 2004;50:1051–65.

[19] Szkudlarek M, Narvestad E, Klarlund M, et al.Ultrasonography for the metatarsophalangealjoints in rheumatoid arthritis. Comparisonwith magnetic resonance imaging, conventionalradiography and clinical examination. ArthritisRheum 2004;50:2103–12.

[20] Wakefield RJ, Karim Z, Conaghan PJ, et al.Sonography is more sensitive than clinical exam-ination at detecting synovitis in the metatarso-phalangeal joints. Arthritis Rheum 1999;42:S352.

[21] Wakefield RJ, Green MJ, Marzo-Ortega H, et al.Should oligoarthritis be reclassified? Ultrasoundreveals a high prevalence of subclinical disease.Ann Rheum Dis 2004;63:382–5.

[22] Keen HI, Brown AK, Wakefield RJ, et al. MRI andmusculoskeletal ultrasonography as diagnostictools in early arthritis. Rheum Dis Clin NorthAm 2005;31:699–714.

[23] Hirohata S, Sakakibara J. Angioneogenesis asa possible elusive triggering factor in rheumatoidarthritis. Lancet 1999;353:1331.

[24] Wakefield RJ, Balint PV, Szkudlarek M, et al.Musculoskeletal ultrasound including defini-tions for ultrasonographic pathology. J Rheuma-tol 2005;32:2485–7.

[25] Szkudlarek M, Court-Payen M, Strandberg C,et al. Power Doppler ultrasonography for assess-ment of synovitis in the metacarpophalangealjoints of patients with rheumatoid arthritis. Acomparison with dynamic magnetic resonanceimaging. Arthritis Rheum 2001;44:2018–23.

[26] Terslev L, Torp-Pedersen S, Savnik A, et al. Dopp-ler ultrasound and magnetic resonance imagingof synovial inflammation of the hand in rheu-matoid arthritis: a comparative study. ArthritisRheum 2003;48:2434–41.

[27] Newman JS, Adler RS, Bude RO, et al. Detectionof soft-tissue hyperemia: value of power Doppler

sonography. AJR Am J Roentgenol 1994;163:385–9.

[28] Walther M, Harms H, Krenn V, et al. Correlationof power Doppler sonography with vascularityof the synovial tissue of the knee joint in patientswith osteoarthritis and rheumatoid arthritis.Arthritis Rheum 2001;44:331–8.

[29] Walther M, Harms H, Krenn V, et al. Synovial tis-sue of the hip at power Doppler US: correlationbetween vascularity and power Doppler signal.Radiology 2002;225:225–31.

[30] Newman JS, Laing TJ, McCarthy CJ, et al. PowerDoppler sonography of synovitis: assessment oftherapeutic response - preliminary observations.Radiology 1996;198:582–4.

[31] Hau M, Kneitz C, Tony HP, et al. High resolutionultrasound detects a decrease in pannus vascular-isation of small finger joints in patients withrheumatoid arthritis receiving treatment withsoluble tumor necrosis factor alpha receptor (eta-nercept). Ann Rheum Dis 2002;61:55–8.

[32] Teh J, Stevens K, Williamson L, et al. PowerDoppler ultrasound of rheumatoid synovitis:quantification of therapeutic response. Br J Ra-diol 2003;76:875–9.

[33] Schmidt WA. Doppler sonography in rheumatol-ogy. Best Pract Res Clin Rheumatol 2004;18:827–46.

[34] Skudlarek M, Court-Payen M, Jacobsen S, et al.Interobserver agreement in ultrasonography ofthe finger and toe joints in rheumatoid arthritis.Arthritis Rheum 2003;48:955–62.

[35] Wakefield RJ, D’Agostino MA, Iagnocco A, et al.The OMERACT ultrasound group: status of cur-rent activities and research directions. J Rheuma-tol 2007;34:848–51.

[36] Magarelli N, Guglielmi G, Di Matteo L, et al. Di-agnostic utility of an echo-contrast agent inpatients with synovitis using power Doppler ul-trasound: a preliminary study with comparisonto contrast-enhanced MRI. Eur Radiol 2001;11:1039–46.

[37] Fiocco U, Perro F, Cozzi L, et al. Contrastmedium in power Doppler ultrasound for assess-ment of synovial vascularity: a comparison witharthroscopy. J Rheumatol 2003;30:2170–6.

[38] Klauser A, Demharter J, De Marchi A, et al.Contrast enhanced grey-scale sonography inassessment of joint vascularity in rheumatoidarthritis: results from the IACUS study group.Eur Radiol 2005;15:2404–10.

[39] Farrant JM, O’Connor PJ, Grainger AJ. Advancedimaging in rheumatoid arthritis. Part 2: erosions.Skeletal Radiol 2007;36:381–9.

[40] van der Heijde DM, van Riel PL, van Leeuwen MA,et al. Prognostic factors for radiographic damageand physical disability in early rheumatoid arthri-tis. A prospective follow-up study of 147 patients.Br J Rheumatol 1992;31:519–25.

[41] McQueen FM, Stewart N, Crabbe J, et al. Mag-netic resonance imaging of the wrist in earlyrheumatoid arthritis reveals a high prevalence

Lopez-Ben736

of erosions at 4 months after symptom onset.Ann Rheum Dis 1998;57:350–6.

[42] Wakefield RJ, Gibbon WW, Conaghan PG, et al.The value of sonography in the detection ofbone erosions in patients with rheumatoidarthritis. A comparison with conventional radi-ography. Arthritis Rheum 2000;43:2762–70.

[43] Benton N, Stewart N, Crabbe J, et al. MRI of thewrist in early rheumatoid arthritis can be used topredict functional outcome at 6 years. AnnRheum Dis 2004;63:555–61.

[44] Alarcon GS, Lopez-Ben R, Moreland LW. High-resolution ultrasound for the study of targetjoints in rheumatoid arthritis. Arthritis Rheum2002;46:1969–70.

[45] Bajaj S, Lopez-Ben R, Oster R, et al. Ultrasounddetects rapid progression of erosive disease inearly rheumatoid arthritis: a prospective longitu-dinal study. Skeletal Radiol 2007;36:123–8.

[46] Boutry N, Larde A, Demondion X, et al. Metacar-pophalangeal joints at US in asymptomaticvolunteers and cadaveric specimens. Radiology2004;232:716–24.

[47] Magnani M, Salizzoni E, Mule R, et al. Ultrasonog-raphy detection of early bone erosions in the meta-carpophalangeal joints of patients with rheumatoidarthritis. Clin Exp Rheumatol 2004;22:743–8.

[48] Combe B. Early rheumatoid arthritis: strategiesfor prevention and management. Best Pract ResClin Rheumatol 2007;21(1):27–42.



737

Ultrasound Guided MusculoskeletalProceduresDavid Fessell, MDa,*, Marnix van Holsbeeck, MDb

- Ultrasound-guided aspiration of joint,bursal, and peri-articular fluidcollections

General techniqueShoulderElbowWrist and handHipKnee

Ankle- Ultrasound-guided injections- Ultrasound-guided aspiration of calcific

tendonitis- Ultrasound-guided tenotomy- Ultrasound-guided biopsy of soft tissue

masses- Summary- References

Specific ultrasound (US)-guided procedures to be emergency department, or an office setting. The
reviewed in this article include aspiration of joint,bursal, and periarticular fluid collections; aspira-tion of calcific tendinitis; injection of joints andbursa, tenotomy (needling) of tendinosis; andbiopsy of soft tissue masses. These proceduresmay be performed with imaging guidance, or insome cases may be performed blindly, using onlyanatomic landmarks. Imaging guidance can includefluoroscopy, CT, or US, and has several advantagesover procedures done using only anatomic land-marks. When imaging guidance is used, the proce-dure can be done safely and successfully, avoidingnerves, vessels, tendons, and other structures.With US guidance, the radiologist can visualizethe needle tip continually and assure that the nee-dle is placed precisely in the desired location.
US has several additional advantages over CT orfluoroscopic-guided procedures. US is relativelyinexpensive and widely available. It is portableand can be done at the bedside, in the ICU,

a Department of Radiology, University of Michigan Ho2910Q, 1500 East Medical Center Drive, Ann Arbor, MI 4b Department of Radiology, Henry Ford Hospital, 2USA* Corresponding author.E-mail address: [email protected] (D. Fessell).


contralateral joint or limb can be evaluated easilyfor comparison and detection of subtle abnormali-ties. Correlation can be made with the patient’s siteof pain, with direct visualization of the anatomyand pathology at the symptomatic site. Pressure withthe transducer can be used to elicit symptoms orassess for compressibility of a fluid collection versusa solid mass. Procedures can be performed rapidlyand efficiently with a seamless transition betweensonographic evaluation and aspiration or biopsy.

Ultrasound-guided aspiration of joint,bursal, and peri-articular fluid collections

General technique

The technique for US-guided joint aspiration hasbeen described previously [1,2]. Sonographic evalu-ation of the joint and surrounding soft tissues intwo planes is first performed to assess for joint fluid,

spitals and Health Centers, Taubman Center, Room8109-5326, USA799 West Grand Boulevard, Detroit, MI 48202,




Fessell & van Holsbeeck738

bursal fluid, or other soft tissue fluid collectionssuch as an abscess (Fig. 1). This allows detectionof bursal or soft tissue collections that would beundetected by fluoroscopic or blind aspiration,and prevents potential contamination of an asepticjoint during blind or fluoroscopic aspirationthrough overlying infected tissue such as septic te-nosynovitis, or soft tissue abscess (Figs. 2 and 3).In some cases, sonographic evaluation may renderaspiration unnecessary, if no joint or soft tissuefluid is detected. If clinical suspicion is high, andno joint or soft tissue fluid is identified, injectionof nonbacteriostatic, sterile saline followed by jointaspiration also can be performed.

The approach for US-guided joint aspiration is inmost cases similar to that used for arthrography, butcan be optimized by tailoring aspiration to thespecific location where fluid is visualized by US.A 20-gauge spinal needle with stylet and commer-cial arthrogram tray typically is used. A 7.5 MHz(or higher frequency) transducer is recommendedfor most joints. Hip aspiration may require a curvi-linear 5 MHz or lower frequency transducer. A com-pact or hockey stick transducer is used commonly,especially for smaller joints, and often providessuperior visualization of the needle within thesoft tissues when compared with a transducerwith a larger footprint.

With ultrasound, intra-articular joint pathologymay be anechoic, hypoechoic, mixed, or less com-monly hyperechoic. The sonographic appearanceof a joint effusion is not predictive of infection. Fluidaspiration usually is more successful from the moreanechoic regions, while synovial or soft tissue biopsyis more successful from the hypoechoic or mixed

Fig. 1. (A) Coronal sonogram at the lateral aspect of a profluid collection (arrowheads). Fluoroscopic hip joint aspirthis fluid collection. (B) Transverse sonogram at the later(arrow) measuring 3.6 cm (� to �) by 3.4 cm (1 to 1) lateThe hypoechoic collection was an abscess and was treate

regions. Doppler evaluation is performed routinely,both of the surrounding soft tissues to exclude vascu-lar structures along the aspiration approach, andalso to evaluate for blood flow within and surround-ing the intra-articular pathology. Some effusionscaused by an infectious or inflammatory etiologycan have increased surrounding flow on Dopplerimaging. The absence of such flow does not excludeinfection, however. Doppler flow within a suspectedjoint effusion is consistent with synovitis, or otherjoint pathology, rather than fluid (Fig. 4) [2]. Theuse of Doppler evaluation in muscoskeletal proce-dures can be summarized as follows:

� Evaluation of joint fluid (no internal Dopp-ler flow) versus synovitis (may have internalflow)—absence of internal flow does notexclude synovitis.

� Evaluation of cystic (no internal Dopplerflow) versus solid soft tissues masses (mayhave internal flow)—absence of internalflow does not exclude a solid mass.

� Evaluation of hyperemia surrounding a jointeffusion—hyperemia can be seen in thesetting of infection but the absence of hyper-emia does not exclude infection.

� Doppler evaluation can aid visualization ofthe needle within the soft tissues.

In the differentiation between complex jointfluid and synovitis, joint recess compressibility,movement of intra-articular contents with trans-ducer pressure, joint recess collapse with jointmovement, and lack of internal flow on color orpower Doppler imaging suggest complex jointfluid.

sthetic hip demonstrates a 9 cm by 3.4 cm hypoechoication 4 days prior yielded no fluid and did not detectal aspect of the hip demonstrates the fluid collectionral to the cortex of the proximal femur (arrowheads).d with surgical incision and drainage.

Fig. 2. Transverse sonogram at the anterior aspect ofthe midfoot demonstrates the extensor digitorumtendons (single arrowheads) and peroneus tertius ten-don (double arrowheads) with surrounding complextenosynovitis (curved arrows). Fluid was aspiratedunder ultrasound guidance and grew Nocardia aster-oides. Fluoroscopic or blind aspiration of the anklejoint could have infected an aseptic ankle joint if theneedle had extended through this septic tenosynovi-tis. (From Fessell DP, Jacobson JA, Craig J, et al. Using so-nography to reveal and aspirate joint effusions. AJRAm J Roentgenol 2000;174:1353–62; with permission.)

Fig. 4. Longitudinal sonogram of the hip demonstratesa hypoechoic effusion (arrows) superficial to the cortexof the femoral neck (arrowheads). Increased surround-ing flow is noted with power Doppler.

Ultrasound Guided Musculoskeletal Procedures 739

After a joint effusion is detected, an appropriatelysized needle is selected by measuring the depthfrom the skin entry point to the deepest portionof the fluid. The skin is marked and the skin entrysite checked for accuracy in both longitudinal andtransverse planes. The skin is cleaned with Betadine(Purdue Pharma, Stamford, Connecticut) or Chlor-aprep (Enturia, Incorporated, Leawood, Kansas),

Fig. 3. Longitudinal ultrasound of the dorsal wristdemonstrates hypoechoic tenosynovitis (small whitearrows) surrounding the extensor tendons (black ar-rows). The radiocarpal joint is noted (large arrow).Blind or fluoroscopic aspiration of the radiocarpaljoint through septic extensor tenosynovitis could in-fect an aseptic radiocarpal joint.

sterile drapes applied, and the transducer coveredwith a sterile probe cover. A freehand aspirationtechnique commonly is used, with constant moni-toring of the needle position with US. If there is dif-ficulty in visualizing the needle tip, minutemovements of the transducer are recommendedrather than advancement of the needle. Dopplerevaluation also can be helpful to detect the needlewithin the soft tissues (Fig. 5). The more parallelthe needle is to the surface of the transducer, thebetter the needle will be visualized as a linear hyper-echoic structure with posterior reverberation arti-fact. US machine settings of a single focal zoneand low persistence have been reported to improveneedle visualization in the soft tissues [3].

Complications secondary to US-guided joint aspi-ration are unusual and should be less frequent thanwith fluoroscopic or blind aspiration given the con-stant visualization of the needle tip during aspira-tion [4]. Potential complications include iatrogenicinfection, bleeding, damage to neurovascular struc-tures, vasovagal reaction, and failure to aspirate fluidor detect infection. Discussion of potential compli-cations should be included in the preprocedure in-formed consent process. Performing aspirationwith the patient in the supine position is optimaland helps decrease any complications secondary toa vasovagal reaction. Difficulty with aspiration usu-ally is secondary to poor visualization of the needleduring the procedure, improper skin marking, or in-ability to distinguish synovitis from fluid on the pre-aspiration ultrasound examination [2]. The use ofsonography for evaluating and guiding joint aspira-tion helps assure a safe and successful aspiration.

Shoulder

Both anterior access and posterior access to theglenohumeral joint have been described [5,6]. Forjoint aspiration, the authors prefer the posterior

Fig. 5. (A) Transverse sonogram during ultrasound-guided hip joint aspiration. The needle is difficult to detect.Arrow denotes the hip joint fluid, and arrowheads outline the cortex of the femoral neck. (B) Same image as(A), with power Doppler showing the aspiration needle (arrow). The use of Doppler can aide visualization ofthe needle during aspiration.

Fig. 6. Diagram illustrating the approach for posterioraspiration of the shoulder. The transducer is placedtransversely at the joint space and, the needle entersfrom a slight lateral to medial approach.


approach, because fluid usually is visualized mostreadily in this location, even when small in amount(Fig. 6). Dynamic scanning from a posterior ap-proach during abduction and adduction of thearm can aid visualization of even minute amountsof joint fluid, surrounding the posterosuperiorlabrum and superior to the humeral head(Fig. 7). For posterior aspiration, the patient issitting upright or leaning forward and must bemonitored closely for any signs of a vasovagal reac-tion. The circumflex scapular vessels and suprascap-ular nerve course medial to the glenoid rim andmust be avoided. Puncturing the joint capsulealong the medial aspect of the humeral head, lateralto the joint space, provides safe and effective access.Using this approach, successful needle placementhas been reported in 24 patients for arthrography,without complication [5]. Because the presence ofjoint fluid distends the joint capsule and makesthe target even larger, sonographically guided jointaspiration is an even simpler procedure than usingsonographic guidance for arthrography.

For aspiration of the shoulder from an anteriorapproach, the patient usually is positioned supine.When scanning axially, the puncture site is the mid-point between the coracoid and anteromedialhumeral head, similar to standard arthrography.The cephalic vein, axillary artery, and brachialplexus course medial to the coracoid. The needletip therefore always must remain lateral to thecoracoid. Using an anterior approach, successfulneedle placement has been reported in 50 patientsfor arthrography, without complication [6]. At theauthors institution typically only aspirate the

glenohumeral joint from an anterior approach ina patient who has to remain supine, or in a patientwho has loculated fluid located only in the anteriorjoint space on the preaspiration sonogram.

The subacromial–subdeltoid bursa also can beaspirated with sonographic guidance (Fig. 8). Theentire shoulder always should be scanned withultrasound to reveal such collections before any

Fig. 7. Transverse ultrasound of the posterior gleno-humeral joint demonstrates a moderate amount offluid (large arrows) surrounding the triangular andechogenic posterior labrum (small arrows). Arrow-heads denote the cortex of the humeral head.


aspiration of the glenohumeral joint. Such bursalfluid collections would not be detected with fluoro-scopic joint aspiration or joint aspiration based onanatomic landmarks. Using sonography, septicbursitis thus can be aspirated without the dangerof the needle going too deep and into the gleno-humeral joint as potentially could happen withan aspiration based on anatomic landmarks or anaspiration using fluoroscopy.

Fig. 8. (A) Longitudinal sonogram of the distal supraspinastrates a small amount of fluid in the bursa (large arrows)spinatus tendon. (B) Longitudinal sonogram of the sudemonstrates a small amount of fluid within the bursa (noted within the bursa. Arrowhead denotes the cortex offluid were aspirated under ultrasound guidance. Sonograpbursa without danger of entering the glenohumeral join

Although seen infrequently, acromioclavicular(AC) joint sepsis is seen more commonly inimmune-compromised patients and intravenousdrug abusers [7]. Clinically, the presentation maymimic glenohumeral joint infection. Sonographycan exclude a septic glenohumeral joint and diag-nose an AC joint effusion, preventing a potentiallymissed diagnosis. Sonography of the acromioclavic-ular joint is performed in both the sagittal andcoronal planes to evaluate for distention of thejoint. Comparison with the contralateral side isuseful, as well as noting pain with transducer pres-sure on the acromioclavicular joint. The glenohum-eral joint and subacromial–subdeltoid bursa alsomust be evaluated with ultrasound to exclude fluidat these sites. The normal AC joint has been re-ported to have less than 3 mm of fluid, measuredfrom the joint capsule to the cortex [7]. Fluid collec-tions communicating with the acromioclavicularjoint most commonly are caused by an infectedjoint or secondary to a ganglion cyst (Fig. 9) [8].

Paralabral cysts of the spinoglenoid and supra-scapular notches commonly are associated withtears of the glenoid labrum (Fig. 10) [9]. Spinogle-noid notch cysts usually are aspirated from a poste-rior approach, similar to posterior shoulder jointaspiration (see Fig. 6). The larger the needle, theeasier the aspiration of the thick, gelatinous gan-glion fluid. If possible, the use of a 15 gauge, orlarger needle, is helpful. Paralabral cyst aspirationtypically is considered when there is suprascapularnerve compression as a temporizing measure beforesurgery. Ganglion cysts have been reported in theanterior shoulder, including the followinglocations: between the deltoid and subscapularistendon, between deltoid and biceps, and inferior

tus tendon and subacromial–subdeltoid bursa demon-. Small arrows denote the bursal surface of the supra-bacromial–subdeltoid bursa in a different patientsmall arrows). The aspiration needle (large arrow) isthe greater tuberosity. Two milliliters of thick, yellowhic guidance can assure safe aspiration of an infected

t space.

Fig. 9. (A) Longitudinal ultrasound demonstrates a 5.1 � 4.5 � 1.6 cm mixed anechoic and hypoechoic fluid col-lection (small arrows) extending from the acromioclavicular joint (large arrow). (B) Longitudinal sonogram(merged split-screen image) demonstrates the fluid collection (small arrows), ACJ (large arrow), and distal supra-spinatus tendon (black arrows). Fluid was aspirated under sonographic guidance and grew Staphylococcus.Abbreviations: ACJ, acromioclavicular joint; SST, supraspinatus tendon.


to the coracoacromial ligament [10]. Chiou andcolleagues [10] reported 15 patients who had gan-glion cysts of the anterior aspect of the shoulder, as-pirated with US guidance. Follow-up ranged from 2to 24 months (mean 6.4 months). Thirteen of the15 had marked or complete pain relief, without ev-idence of recurrence of the ganglion or recurrenceof symptoms. Symptom relief in this study wasnot related to the amount of fluid aspirated. Thetwo patients without symptomatic relief followingaspiration also had concomitant rotator cuffpathology. Therefore caution should be exercisedregarding expectations of pain relief in patientswho have concurrent rotator cuff or other shoulderpathology. The approach for aspiration depends onthe location of the cyst, and US guidance affordsa high degree of flexibility in the choice of the aspi-ration approach. Aspiration of shoulder ganglia canbe a painful procedure. Premedication and closemonitoring for a vasovagal reaction is needed. Aspi-ration should be performed with the patient supine,or lying on his or her side whenever possible.

Fig. 10. Transverse ultrasound of the posterior aspectof the glenohumeral joint demonstrates a 1 cm hypoe-choic paralabral cyst (black arrow) in the spinoglenoidnotch with a hypoechoic neck extending laterally(small white arrows) through an irregular and tornposterior labrum. The paralabral cyst was aspiratedunder ultrasound guidance.

Elbow

Anterolateral, posterolateral, and posterior ap-proaches have been described for aspiration of the el-bow [2,11,12]. Palpation and puncture of the softspot at the posterolateral elbow frequently are usedfor blind aspiration. The soft spot is the center ofthe triangle formed by the olecranon process, radialhead, and lateral epicondyle [11]. A lateral approach,with puncture of the radiocapitellar joint, frequentlyis used with fluoroscopy when performing arthrogra-phy. For the posterior approach, the elbow is flexedand the olecranon fossa evaluated with US in longitu-dinal and transverse planes (Fig. 11). This positionoptimizes detection of the smallest joint effusion[13]. Sonography from a posterior approach

demonstrates fluid in the olecranon fossa (Fig. 12).No major neurovascular structures are encounteredwith a posterior approach. Radiologists at the authorsinstitution have used the posterior approach success-fully and without complication.

Wrist and hand

For the radiocarpal joint, a dorsal approach is used foraspiration, with sonographic guidance to avoid ten-dons, nerves, and vessels (Fig. 13). Flexion of the jointcan aid needle placement as with positioning for wrist

Fig. 11. (A) Diagram from a lateral view illustrating aspiration of the elbow from a posterior approach. The nee-dle tip is place in the olecranon fossa. Note that the transducer is oriented transversely, and the needle enterssuperior to the transducer. (B) Diagram from a posterior view illustrates the transverse orientation of the trans-ducer and needle entering superior to the transducer. If there is enough space, a longitudinal approach, withthe needle at the end of the transducer, can also be used.

Fig. 12. Transverse ultrasound of the posterior elbowdemonstrates a hypoechoic effusion (large arrows) inthe olecranon fossa. Small arrows denote the cortexof the olecranon fossa.


arthrography. Fig. 14 demonstrates the sonographicappearance of fluid in the radiocarpal joint. Flowwithin a hypoechoic region on Doppler evaluationcan help distinguish synovitis, which can demon-strate flow on Doppler imaging, from fluid whichdoes not demonstrate internal Doppler signal. Theabsence of flow on Doppler evaluation, however,does not exclude synovitis. Gentle flexion and exten-sion of the wrist during sonography can show fluidcommunicating with the joint and help distinguisha joint effusion from a ganglion cyst. The flexibility af-forded by sonographically guided aspiration allowsplacement of the aspiration needle at the site of max-imal fluid. US evaluation and guidance of aspirationalso allow detection of extensor tenosynovitis, whichclinically could mimic a septic joint. Diagnosis ofsuch extra-articular fluid collections allows propertreatment and helps avoid potential complicationssuch as seeding of an aseptic joint from needle place-ment through an undiagnosed superficial abscess orseptic tenosynovitis (see Fig. 3).

Wrist ganglia are most commonly located dorsally,adjacent to the scapholunate ligament, and at the vo-lar aspect of the wrist, adjacent to the radial artery. AtUS, they are most commonly anechoic, possibly mul-tilocular and multilobular, and may be septated.Smaller ganglion cysts may be hypoechoic and maynot show increased through transmission [14]. UScan detect a ganglion cyst, and US guided aspirationand steroid injection can be used as treatment, withawareness that recurrence may occur (Fig. 15). Dopp-ler imaging can help exclude an aneurysm or othervascular process as the etiology for a wrist mass. Un-like a distended joint recess, wrist ganglion cysts are

typically not compressible, do not deform with jointmovement, and are more likely multilocular.

For aspiration of the metacarpophalangeal joints,proximal interphalangeal joints, and distal inter-phalangeal joints, a dorsomedial, or dorsolateralapproach can be used (Fig. 16). This approachavoids the medial and lateral neurovascular struc-tures and volar and dorsal tendons. The specific ap-proach used in a given case can be tailored to thesite of greatest fluid accumulation and site of easiestaspiration. When compared with attempted intra-articular needle placement based on anatomic land-marks, US-guided placement is more accurate bya wide margin, 56% to 96% [15]. US guidance

Fig. 13. Diagram illustrating aspiration of the radio-carpal joint from a dorsal approach. Transducer isplaced transversely at the level of the radiocarpaljoint. The tip of the needle is placed in the radiocar-pal space.


also is more successful for aspiration of joint fluid,versus aspiration using only anatomic landmarks,especially in the small joints. Balint and colleagues[16] showed aspiration based on landmarks wassuccessful in 32%, versus 97% with US guidance.

Hip

In the authors’ practice, the hip is the joint mostcommonly requested for aspiration. At the authors’

Fig. 14. (A) Longitudinal ultrasound of the wrist demons(large arrow). Distal radius (left gray arrow) and carpal boficial extensor tendon (small arrows) is intact. (B) Longia small amount of hypoechoic fluid (black arrows) in the rpal bones (white arrows). Absence of flow within this hypjoint fluid from synovitis. Arrowhead denotes the distal r

institution, they advocate the use of US for evalua-tion of hip joint fluid and soft tissue fluid collec-tions about the hip, especially in the patient whohas undergone a hip arthroplasty. In such patientsinfected soft tissue fluid collections are not unusual,and commonly would not be detected by a blind orfluoroscopic aspiration. Optimal patient position-ing for sonographic evaluation of the hip is withthe patient supine with the hip extended and theleg in slight abduction. This position tightens theposterior capsule and forces joint fluid into the an-terior portion of the hip capsule, aiding aspirationfrom an anterior approach [17].

Given the depth of the hip joint, a 7.5 MHz or 5MHz transducer most often is used. The transduceris oriented along the long axis of the femoral neck.This allows visualization of the femoral vessels,joint fluid, and needle as it enters the joint capsule.For safe aspiration, palpation and marking of thefemoral artery are performed. Joint aspiration isperformed lateral to the neurovascular bundle, usu-ally by several centimeters (Fig. 17).

Displacement of the hip joint capsule away fromthe femoral neck is noted with a hip effusion(Fig. 18). Contralateral comparison is performedeasily with US, and aids detection of subtle or smalleffusions. A 2 mm or greater difference in jointdistention between the symptomatic and asymp-tomatic hip has been reported as a helpful discrim-inator for the presence of abnormal fluid in the hipjoint [18]. Additional findings that may be seenwith a septic hip include thickening of the joint cap-sule and cortical irregularity of the proximal femurdeep to the effusion [18]. Preaspiration Dopplerevaluation to discriminate synovitis from fluid,and sonographic visualization of the needle tip inthe region of interest, can help assure a successfulaspiration. Although joint aspiration does nothave an accuracy of 100% compared with surgical

trates a small amount of fluid dorsal to the scaphoidnes (middle and right gray arrows) are noted. Super-

tudinal ultrasound of a different wrist demonstratesadiocarpal and midcarpal joints, superficial to the car-oechoic region on Doppler imaging helps distinguishadius.

Fig. 15. (A) Ultrasound of the volar wrist demonstrates a 2.4 � 2.2 cm (between the 1 and � calipers respectively)anechoic, lobulated ganglion cyst at the level of the radiocarpal joint (joint space not shown). (B) Sonographicguided aspiration demonstrates the needle tip (large arrow) within the ganglion cyst (small arrows).

Fig. 16. Diagram illustrating sonographic guidance foraspiration of the metacarpal–phalangeal joint. Trans-ducer is oriented transversely at the level of the joint.


findings, it can be a helpful procedure, especiallycombined with US of the soft tissues to exclude bur-sal fluid or soft tissue abscess. Aspiration of thejoint is most helpful when fluid is obtained andconfirms a clinical suspicion of infection. Aspira-tion is less helpful when no fluid can be aspirated.In this situation, a negative aspiration can suggestthe absence of infection but does not exclude infec-tion definitively. This is especially true in the settingof a total hip arthroplasty [19].

In cases with a hip prosthesis present, US findingsof capsular distention may have decreased accuracy[19,20]. This may be secondary to hypoechoic scartissue at the expected site of the joint capsule, whichcan mimic hypoechoic joint fluid (Fig. 19). Dopp-ler evaluation can be especially helpful in such casesand should be included in the US evaluation. Flowwithin the intra-articular, hypoechoic region is con-sistent with synovitis, scar, or fibrous tissue ratherthan hypoechoic joint fluid. In the setting of a hipprosthesis, it is also important to image the incisionsite and surrounding soft tissues for fluid collection.The presence of joint effusion and associated extra-articular fluid collection suggests infection [21].

Complications from hip aspiration are very rare.In a series of 800 aspirations performed by Bermanand colleagues [4], no iatrogenic hip infectionswere noted. Other complications such as hema-toma are also unusual. Inability to differentiate sy-novitis from joint fluid and thus inability toaspirate fluid may be the most commonly encoun-tered difficulty with hip aspiration. Again, Dopplerevaluation may be helpful; however, aspiration ulti-mately may be needed to assess for joint fluid.

Numerous extra-articular fluid collections com-monly are seen about the hip, including greatertrochanteric bursitis, iliopsoas bursitis, and less

Fig. 17. Diagram of hip joint aspiration. Note trans-ducer and aspiration needle are oriented along theaxis of the femoral neck (dotted line). Safe aspirationis performed lateral to the femoral vessels.


commonly obturator bursitis (Figs. 20 and 21). Un-like the bursae about the greater trochanter, theiliopsoas bursa may communicate to the hip joint;therefore, hip joint pathology and effusion may bethe cause of iliopsoas bursa distention. Soft tissueabscesses also can occur about the hip. These fluidcollections would be undetected by a fluoroscopicor blind aspiration of the hip. Given their depth,they may not be detected on physical examination.Sonography allows rapid and inexpensive detectionof these soft tissue fluid collections. For greater tro-chanteric bursitis, a lateral aspiration approach gen-erally is used. For iliopsoas bursitis, an anterior oranterolateral approach is often optimal. The flexi-bility of sonographic aspiration is one its strengthsand the precise location of the fluid collection andadjacent neurovascular structures determine the ex-act aspiration approach in each case. Fig. 22 illus-trates a posterior approach for aspirating loculatedfluid at the posterior aspect of the hip.

Knee

US has been shown to be more sensitive than clin-ical examination for detecting knee effusions andBaker’s cysts [22]. Blind knee aspiration often is per-formed easily using anatomic landmarks, especiallyif the effusion is moderate or large in size. Small orloculated effusions, however, can be aspirated usingsonographic guidance. The patient is supine withthe knee extended. Scanning of the suprapatellar re-cess and surrounding soft tissues is performed in

longitudinal (Fig. 23) and transverse orientations(Fig. 24) relative to the quadriceps tendon. The lat-eral aspect of the suprapatellar recess is the locationwhere small effusions are usually first detectable. Itis important not to apply too much pressure withthe transducer, as this may cause collapse the me-dial or lateral recesses. In partial knee flexion, jointfluid often predominately collects anteriorly, deepto the quadriceps tendon. A small amount of jointfluid is physiologic, and comparison to the contra-lateral knee aids determination of abnormal fluid.Aspiration can be performed from a medial or lat-eral approach and is usually done in a transverseorientation relative to the axis of the femur and pa-tella (Fig. 25). The precise location and entry pointcan be determined based on the site of greatest fluidaccumulation.

Numerous bursa and cysts can exist about theknee. These include the pes anserine bursa andsemimembranosus medial collateral ligamentbursa, Baker’s cysts, meniscal cysts, and ganglioncysts. All can be detected and aspirated with sono-graphic guidance. Aspiration of meniscal cysts usingUS guidance has been reported to provide symp-tomatic relief in two-thirds of cases, followed foran average of 10 months after aspiration [23]. Aspi-ration of posterior cruciate ganglion cysts also hasbeen reported [24]. US-guided aspiration of Baker’scysts can be performed for symptomatic relief andas a temporizing measure, because recurrence isnot uncommon following aspiration. Aspirationwith steroid injection may help prevent recurrencein some cases. When imaging a Baker’s cyst, visual-ization of fluid extending between the medial headof the gastrocnemius tendon and the semimembra-nosus tendon is essential to avoid confusion withother cystic masses about the knee (Fig. 26) [25].Abscesses and other cystic masses such as cystic lip-osarcoma, and myxoma, can occur in the poplitealfossa but do not have a neck extending between thesemimembranosus and medial head of the gastroc-nemius tendons (Fig. 27).

Ankle

For aspiration of the ankle joint, the patient is su-pine; the knee is flexed, and the plantar aspect ofthe foot is flush with the stretcher (Fig. 28) [2].Plantar flexion optimizes detection of an ankle effu-sion by distending the anterior joint recess. Normalankle joint fluid can measure up to 3 mm in thick-ness (anterior to posterior dimension) and can beasymmetric compared with the asymptomatic ankle[26]. Prior to aspiration, the dorsalis pedis artery islocalized with sonography and marked on the skin.The deep peroneal nerve courses immediately lat-eral to the artery. A skin entry site is chosen to avoid

Fig. 18. (A) Diagram showing the normal hip joint with superficial and deep layers of the capsule. The adjacentand opposed layers of the joint capsule should not be mistaken for hypoechoic fluid at sonography. (B) Diagramshowing a hip joint effusion distending the joint capsule. (C) Longitudinal ultrasound shows an anechoic hipjoint effusion (between the cursors) distending the capsule of the hip joint over the femoral neck. (Courtesyof J. Jacobson, MD, Ann Arbor, MI.)

Fig. 19. Longitudinal sonogram of a hypoechoic hip ef-fusion in a patient status after hip arthroplasty. Effusionis noted deep to the long arrow marking the superficialportion of the joint capsule. The bone-to-capsule dis-tance is11mm, measuredbetween theshortarrows. Re-verberation artifact is denoted by the curved arrowposterior to the metal flange of the hip prosthesis.(From Fessell DP, Jacobson JA, Craig J, et al. Using sonog-raphy to reveal and aspirate joint effusions. AJR Am JRoentgenol 2000;174:1353–62; with permission.)


the neurovascular bundle and extensor tendons(Fig. 29). The needle can be visualized throughoutits course, ensuring a safe and successful aspiration.

Septic tenosynovitis of the extensor tendons canmimic a septic joint clinically. Sonography can de-tect such extra-articular fluid collections and guideaspiration. This avoids potentially infecting anaseptic joint by blind or fluoroscopic aspirationthrough overlying septic tenosynovitis or othersources of soft tissue infection (see Fig. 2) [2].

Ganglion cysts about the ankle are relativelycommon and frequently located at the lateral an-kle, related to the subtalar joint and sinus tarsi(Fig. 30). Surgical resection and obliteration ofthe neck of the ganglion is the mainstay of treat-ment. Aspiration does not obliterate the neck ofthe cyst; therefore cyst recurrence is not uncommonfollowing aspiration. In some cases, US-guidedaspiration may be requested and can be used asa temporizing measure or used as treatment innonsurgical candidates. Injection of corticosteroidsfollowing aspiration may help prevent recurrence[27].

Fig. 20. (A) Longitudinal sonogram at the posterolateral aspect of the hip demonstrating fluid distending thegreater trochanteric bursa (arrows). Arrowheads denote the cortex of the greater trochanter. (B) Transversesonogram at the posterolateral aspect of the hip demonstrating fluid distending the greater trochanteric bursa(arrows). Arrowhead denotes the cortex of the GT. (C) Axial T2 weighted magnetic resonance sequence with fatsaturation in the same patient demonstrates the fluid in the greater trochanteric bursa (arrows). Abbreviations:F/S, femoral shaft; GT, greater trochanter.


Ultrasound-guided injections

US also can be used to guide injections of steroidor anesthetic into joints and bursae, and for treat-ment of ganglion cysts, Morton’s neuroma, andplantar fasciitis (see Box 1). The technique forplacing the needle in the joint or bursa is as de-scribed for aspiration. There are several advantagesof US guidance for musculoskeletal injections.The needle tip can be visualized constantly andmonitored for correct positioning. The steroid oranesthetic also can be injected precisely at the de-sired site. Injection within the substance of a ten-don, which has been associated with tendonrupture and degeneration, thus can be avoided[3]. Prior to injection, the joint, bursa or tendon

sheath should be aspirated, so that the injectedmedication is not diluted by fluid present in the in-jected space. The aspirated fluid can be sent foranalysis; however, septic joint fluid, septic bursalfluid, or septic tenosynovitis should be excludedclinically or by other means before the injectionof steroids.

Ultrasound-guided aspiration of calcifictendonitis

Calcific tendonitis can be treated by variousmethods, including anti-inflammatory drugs, phys-ical therapy and steroid injection. When conserva-tive therapy is unsuccessful, treatment can includeopen or arthroscopic surgery, US-guided aspiration,

Fig. 21. (A) Transverse sonogram demonstrates a hypoechoic collection in the right iliopsoas bursa (arrow).Doppler shows the femoral vessels at the medial aspect of the bursa. Arrowheads denote the cortex of the fem-oral head. (B) Axial T2 weighted magnetic resonance sequence without fat saturation demonstrates a 2.8 cmfluid collection in the right iliopsoas bursa (white arrow) with a small posterior communication to the righthip joint. Note a tiny amount of fluid in the left iliopsoas bursa (black arrow).

Fig. 22. (A) Coronal short T1 inversion recovery magnetic resonance sequence demonstrates a lobulated fluidcollection (arrow) at the posterior aspect of the ilium, superior to the right hip joint. (B) Transverse sonogramat the posterior aspect of the hip, at the site of the fluid collection noted above demonstrates a lobulated, hy-poechoic collection (arrow) adjacent to the cortex of the ilium (arrowheads). (C) Transverse sonogram demon-strates the aspiration needle (large arrows) in the fluid collection (small arrow). Arrowhead denotes the cortexof the ilium.


Fig. 23. Sagittal sonogram of a suprapatellar effusion(medium-sized arrows), deep to the quadriceps ten-don (small arrows). The patella is noted by the largearrow.

Fig. 25. Diagram illustrating aspiration of the kneefrom a lateral approach. The needle position is almosthorizontal, parallel to the floor.


and shock wave therapy. When first described, twolarge bore needles (18- to 19-gauge) were usedwith repeated punctures to fragment and aspiratethe calcification. One needle was used for injectionof saline and the second needle for aspiration.Water-soluble cortisone then was injected into thesubacromial–subdeltoid bursa to complete the pro-cedure. Clinical success rates were reported to beexcellent in 74%, moderate in 16%, and poor in10% of patients [32].

In 2001, Aina and colleagues [33] describeda modified technique using a single, 22-gauge nee-dle. An anteroposterior axis of the needle was recom-mended during aspiration, with the needle keptparallel to the horizontal axis (floor of the procedureroom). This orientation aided US localization of theneedle and helped prevent reinjection of aspiratedcalcium. If multiple calcifications were noted, thespecific one for aspiration was chosen based onthe largest size, the calcification associated with focaltendon swelling, or the most symptomatic with UStransducer pressure. Using US guidance, the needlewas placed in the center of the calcification andthe needle tip gently rotated followed by attempted

Fig. 24. Transverse ultrasound of a small amount offluid in the lateral aspect of the suprapatellar recess(small arrows). The patella is denoted by the largearrow.

aspiration. If the consistency of the calcification waspaste-like; successive injection and aspiration of li-docaine was performed in an attempt to removethe calcification. Given the horizontal orientationof the syringe, the dense, white aspirate accumulatedin the dependent portion of the syringe (Fig. 31). Ifthe calcification was very hard and could be aspi-rated, grinding of the calcification was performedby means of gentle rotation of the needle tip in thehope of accelerating resumption. A mixture of ste-roid and anesthetic then was injected at the bursalsurface of the tendon and in the subacromial–subdeltoid bursa. In this study, the best clinicalresults were seen in those patients in whom calciumwas aspirated successfully [33].

It may be most beneficial to first use a fine needle(20- or 22-gauge) for aspiration, followed by a largerbore needle if no calcium can be aspirated; howeverdata using this technique have not been reported[33]. At the authors’ institution, the authors gener-ally use a 20-gauge needle and first attempt aspira-tion. If no calcium can be aspirated, they attempt tobreak up the calcification with the single needle. In-jection of approximately 1 cc of lidocaine within

Fig. 26. Transverse ultrasound of the popliteal fossademonstrating a Baker’s cyst, measuring 3.6 cm inmedial-to-lateral dimension, with internal debris.For confident diagnosis of a Baker’s cyst, an extensionof fluid (small white arrows) must be noted betweenthe semimembranosus tendon (white circle) and themedial head of gastrocnemius tendon (arrowhead).

Fig. 27. Sonogram of the popliteal fossa demonstratesan 8.6 cm (1 to 1) � 3.0 cm (� to �) hypoechoic,poorly defined structure with internal septations.Incision and drainage revealed an abscess.


the calcification is first performed before any at-tempted aspiration. This dilutes the calcificationand creates a pressure effect within the tissue andaids aspiration. Serial injection of lidocaine and as-piration of the calcification are usually successful. Amixture of corticosteroid and anesthetic is injectedinto the subacromial–subdeltoid bursa followingaspiration to help prevent postprocedure bursitis.

Krasny and colleagues [34] compared US-guidedneedling in conjunction with shock wave therapyversus shock wave therapy alone for treating calcifictendonitis of the shoulder. US-guided needlingcombined with shock wave therapy gave

Fig. 28. (A) Diagram of the ankle joint from a lateral view ijoint aspiration. The tip of the needle is placed into thetalus. (B) Diagram of the ankle joint from an anterior vifor ankle joint aspiration.

significantly better outcome. To the authors’ knowl-edge, no study has compared US-guided needlingin conjunction with shock wave therapy with US-guided needling alone.

Ultrasound-guided tenotomy

Sonographically guided percutaneous needling ofa region of tendinosis also is known as tenotomy.This technique has been reported to be a safe andeffective treatment of tendinosis of the common ex-tensor tendon of the elbow, also known as tennis el-bow [35]. Compared with other treatment optionssuch as open or arthroscopic debridement, US-guided tenotomy is quick and easy and has lowmorbidity and a very low to nonexistent complica-tion rate [35]. The procedure is performed in thosepatients who have failed conservative managementsuch as blind corticosteroid injection, nonsteroidalanti-inflammatory medical treatment, bracing/splinting, and physical therapy. Sonography of theextensor tendon origin first is performed to confirmthe diagnosis. Typically, tendinosis of the commonextensor tendon is seen as tendon thickening withhypoechogenicity and heterogeneity of the tendon.Intrasubstance tendon tears and small regions ofcalcification and enthesophytes at the tendon at-tachment also may be seen.

Following the diagnostic US to identify and local-ize the region of tendinosis, the skin, subcutaneous

llustrating transducer and needle placement for ankleintra-articular space, along the anterior cortex of theew demonstrating transducer and needle placement

Fig. 29. Longitudinal sagittal power Doppler ultra-sound (US) at the anterior aspect of the ankle jointdemonstrates a hypoechoic joint effusion (small ar-rows) deep to the dorsalis pedis artery. Single largearrow denotes the cortex of the tibia, and doublelarge arrows denote the cortex of the talus. The effu-sion was aspirated under US guidance, avoiding thevessels and tendons.

Box 1: Use of ultrasound for guidancefor musculoskeletal injections

Joint injection [3,5,6,28]Tendon sheath injection [3,28–30]

Biceps brachii tendon, long head (shoulder)Tibialis posterior tendonFlexor hallucis longus (ankle)Peroneal tendons (ankle)Extensor pollicis brevis and abductor pollicis

longus (wrist): for de Quervain’stenosynovitisIliopsoas tendon (hip): for snappingconditions

Bursal injection [3]

Retrocalcaneal (ankle)Subacromial–subdeltoid (shoulder)Greater trochanter (hip)Iliopsoas (hip)Pes anserine (knee)Olecranon bursa (elbow)Prepatellar bursa (knee)

Ganglion cyst injection, following aspiration[27]Morton’s neuroma injection [3,28]Plantar fascia injection [3,28,31]


tissue, common extensor tendon origin, and perios-teum of the lateral epicondyle are anesthetized withlidocaine or bupivacaine. McShane and colleagues[35] used an 18- or 20-gauge needle, with US guid-ance, to repeatedly fenestrate the area of tendinosis.An inferior-to-superior approach, parallel to thelongitudinal plane of the tendon, was used. Palpa-ble and audible crepitation can be noted on theinitial needle passes, and calcifications or entheso-phytes can be fragmented with the needle tip.McShane and colleagues [35] then inserted the nee-dle a superior to inferior approach, and used theneedle tip used to abrade the periosteum of the lat-eral epicondyle, smoothing any irregularities andfragmenting any enthesophytes. The tendon thenwas injected with a mixture of corticosteroid and

Fig. 30. Lateral ankle ultrasound shows anechoicganglion cyst (arrows). Note needle (arrowheads)entering cyst for aspiration and steroid injection.(Courtesy of J. Jacobson, MD, Ann Arbor, MI.)

bupivacaine. In their hands, the procedure usuallytakes 15 to 20 minutes from start to finish. Postpro-cedure recommendations include a regimen of ice,passive stretching, restricted lifting/repetitive move-ments, and physical therapy.

In 55 consecutive patients treated with US-guidedtenotomy, McShane and colleagues [35] had an av-erage follow-up time of 28 months, with 64% re-porting excellent results, 16% good, 7% fair, and13% poor. There were no adverse events. Eightyfive percent of their patients reported they would re-fer a friend or close relative for the procedure.

US-guided tenotomy also has been reported fortreatment of chronic Achilles and patellar tendinop-athy. Color Doppler evaluation may demonstrateincreased flow in the region of tendinosis (Figs. 32and 33). As with chronic extensor tendinosis, a nee-dle can be used to tenotomize the Achilles or patellartendon. Use of a scalpel, rather than a needle, alsohas been reported. In the studies by Testa and col-leagues [36,37], a #11 scalpel was used, under USguidance, to puncture and tenotomize the tendon.Flexion and extension of the knee or ankle, withthe scalpel in the tendon, was used to expand the re-gion of treatment. Results were similar for both theAchilles and patellar tendons, with approximately73% of patients reporting excellent or good resultson follow-up of at least 2 years. No major complica-tions were reported. The tenotomy procedure didnot hinder surgical treatment in those patients

Fig. 31. (A) Longitudinal sonogram of the distal supraspinatus tendon at its insertion on the greater tuberosity.Focus of linear, echogenic calcification is noted (large arrow) with needle (small arrows) extending through theregion of calcification during ultrasound (US)-guided aspiration. (B) Longitudinal sonogram of the distal supra-spinatus tendon in a different patient. Focus of globular, echogenic calcification is noted (large arrows) withneedle (small arrows) extending through the region of calcification during US-guided aspiration. (C) Photo-graph of the syringe following US-guided aspiration of calcific tendonitis. The white material in the dependentportion of the syringe is the aspirated calcium. (Fig 31C, Courtesy of J. Jacobson, MD, Ann Arbor, MI.)


who had unsatisfactory results from tenotomy. Lesssuccessful treatment with tenotomy was seen inAchilles tendons with marked paratenon involve-ment, multiple nodular regions, or tendinopathygreater than 3 cm in length. Insertional patellar ten-dinopathy also was treated less successfully with te-notomy compared with tendinopathy in the body ofthe tendon. Corticosteroid injection was not used asa part of these procedures.

Ultrasound-guided biopsy of softtissue masses

Soft tissue masses frequently are biopsied percuta-neously, using a core biopsy system. Dependingon the specific size, location, and lesion characteris-tics, biopsy with CT or US guidance may be needed.Although sonography often cannot provide a spe-cific diagnosis of a given soft tissue tumor, its speed,efficiency, cost, portability, availability, and ease ofvisualizing vessels offer advantages over CT forguiding many biopsies. With US guidance, the nee-dle tip also can be visualized constantly, which in-creases the chance of a successful and safe biopsy(Fig. 34). In tumors that have regions of solid and

cystic or necrotic areas, the solid areas have thehighest yield, and the needle tip should be posi-tioned for biopsy of these regions (Fig. 35). Cer-tainly it is an advantage to the patient, clinician,and radiologist if US-guided biopsy can be offeredwhen it provides an advantage over blind or CT-guided biopsy.

The biopsy approach must be chosen in conjunc-tion with the orthopedic oncologist, because the bi-opsy tract may be seeded and may need to beresected if pathologic analysis reveals a malignantprimary tumor [38]. The most advantageous formof biopsy, whether imaging-guided or open surgicalbiopsy, can be determined by means of close collab-oration between the radiologist and orthopedic on-cologist. For US-guided biopsies, Torriani advocatesat least five core biopsies with a 14-gauge auto-mated biopsy gun. Lopez and colleagues [39] usean 18-gauge needle and an average of four biopsies,or a 14-gauge needle for suspected fatty masses. Theauthors routinely use a coaxial system with a 17-gauge introducer needle through which multiple18-gauge core biopsies are taken. Therefore, if fineneedle aspiration is performed, it is optimal to ob-tain these samples first, before obtaining any corebiopsy samples, because bleeding secondary to

Fig. 32. (A) Longitudinal sonogram of the proximal aspect of the patellar tendon demonstrates thickening andhypoechogenicity extending 1.3 cm (between the 1 cursors) from the proximal patellar attachment. Findingsare consistent with tendinosis. (B) Longitudinal ultrasound (US) with power Doppler imaging demonstrates hy-peremia of the region of tendinosis. (C) Longitudinal US during tenotomy demonstrates the needle (arrows)within the region of tendinosis. Needle is well-visualized when parallel to the surface of the US transducer.


the core biopsy sample can render a fine needle as-piration nondiagnostic. Core biopsy samples areusually more accurate and diagnostic comparedwith fine needle aspiration of soft tissue masses[38–40]. The introducer needle can be angled toobtain samples from different areas of the mass.

Fig. 33. (A) Longitudinal ultrasound (US) of the Achilles tening and hypoechogenicity with increased flow on colorand arrowhead denotes cortical irregularity at the calcademonstrates the needle (arrow) within the region of teis well-visualized when parallel to the surface of the US t

Following the biopsy, direct pressure should beheld for 15 minutes, and a compression bandageshould be used for 12 to 24 hours. At least 30 min-utes of observation in the department after biopsy isprudent to assess for bleeding or neurovascularcomplications [38].

endon insertion on the calcaneus demonstrates thick-Doppler imaging. Arrows denote the Achilles tendon,neal insertion. (B) Longitudinal US during tenotomyndonosis. Arrows denote the Achilles tendon. Needleransducer.

Fig. 34. (A) Sonogram demonstrates a hypoechoic mass in the thigh measuring 10 � 7 mm (large arrow) super-ficial to a subcutaneous vessel (small arrows). Clinically, there was concern for recurrent sarcoma at this site. (B)Ultrasound guided biopsy demonstrates needle (large arrow) within the mass (small arrows). Needle is well-visualized when parallel to the surface of the ultrasound transducer. Pathology revealed recurrent high-gradesarcoma.


Myxoid tumors or largely cystic tumors may notyield enough tissue for definitive diagnosis usinga core biopsy technique. Aspiration of fluid with cy-tologic analysis can be performed with US guid-ance. Ultimately, surgical resection may be neededfor definitive diagnosis in such cases. Althoughsoft tissue cartilaginous lesions are uncommon, itis often difficult to subtype and grade these lesions

Fig. 35. (A) Longitudinal sonogram of a mass at the mediashown with an echogenic component (arrow) and a lin(arrowheads). (B) Longitudinal sonogram of the distalwith a linear hypoechoic peripheral nerve exiting the masopsy demonstrates the needle (arrowheads) within the soogy revealed a schwannoma.

based on needle biopsy. In such cases open biopsyor resection may be more efficacious.

In a report of 188 US-guided musculoskeletal bi-opsies performed by Lopez and colleagues [39], nomajor complications were noted. In most series,a complication rate of less than 1% is typical[38,40,41]. Pain, hematoma, and infection are themost common complications, with rare reports of

l aspect of the elbow. Proximal portion of the mass isear hypoechoic peripheral nerve entering the mass

and anechoic portion of the mass (arrow) is showns (arrowheads). (C) Longitudinal sonogram during bi-lid component of the mass seen in figure 35A. Pathol-


more serious complications such as hemorrhage,severe neurologic damage, pneumothorax, or tuber-culous sinus tracts [38]. Accuracy of needle biopsy,compared with findings at surgical resection rangesfrom 60% to 97% [38,39,41–44]. For the patientwho has a soft tissue mass requiring biopsy, optimaloutcome is obtained at a treatment center whenthere is strong communication and cooperation be-tween experienced orthopedic oncologists, muscu-loskeletal radiologists, and musculoskeletalpathologists [39,42].

Summary

US guidance can be used for aspiration, injection,tenotomy, and soft tissue biopsy. The use of USguidance helps assure a safe and successful proce-dure. For each procedure, the precise approachcan be tailored to the specific site of fluid, tendonpathology, or mass. Nerves, vessels, and tendonscan be avoided, because the needle tip is monitoredconstantly with real-time sonographic visualiza-tion. US is widely available, portable, and allowsdynamic evaluation and rapid contralateral com-parison. Appropriate use of this powerful tool canbenefit patients and radiologists.

References

[1] Cardinal E, Chhem RK, Beauregard CG. Ultra-sound-guided interventional procedures in themusculoskeletal system. Radiol Clin North Am1998;36:597–604.

[2] Fessell DP, Jacobson JA, Craig J, et al. Using so-nography to reveal and aspirate joint effusions.AJR Am J Roentgenol 2000;174:1353–62.

[3] Sofka CM, Collins AJ, Adler RS. Use of ultraso-nographic guidance in interventional musculo-skeletal procedures: a review from a singleinstitution. J Ultrasound Med 2001;20:21–6.

[4] Berman L, Fink AM, Wilson D, et al. Technicalnote: identifying and aspirating hip effusions.Br J Radiol 1995;68:306–10.

[5] Cicak N, Matasovic T, Bajraktarevic T. Ultrasono-graphic guidance of needle placement for shoulderarthrography. J Ultrasound Med 1992;11:135–7.

[6] Valls R, Melloni P. Sonographic guidance of needleposition for MR arthrography of the shoulder.AJR Am J Roentgenol 1997;169:845–7.

[7] Widman DS, Craig JG, van Holsbeeck MT. Sono-graphic detection, evaluation, and aspiration ofinfected acromioclavicular joints. Skeletal Radiol2001;30:388–92.

[8] Tshering Vogel DW, Steinbach LS, Hertel R, et al.Acromioclavicular joint cyst: nine cases of a pseu-dotumor of the shoulder. Skeletal Radiol 2005;34:260–5.

[9] Abboud JA, Silverberg D, Glaser DL, et al. Ar-throscopy effectively treats ganglion cysts of the

shoulder. Clin Orthop Relat Res 2006;444:129–33.

[10] Chiou HJ, Chou YH, Wu JJ, et al. Alternative andeffective treatment of shoulder ganglion cyst: ul-trasonographically guided aspiration. J Ultra-sound Med 1999;18:531–5.

[11] Cardone DA, Tallia AF. Diagnostic and therapeu-tic injection of the elbow region. Am Fam Physi-cian 2002;66:2097–100.

[12] Tang CW, Skaggs DL, Kay RM. Elbow aspirationand arthrogram: an alternative method. Am J Or-thop 2001;30:256.

[13] De Maeseneer M, Jacobson JA, Jaovisidha S, et al.Elbow effusions: distribution of joint fluid withflexion and extension and imaging implications.Invest Radiol 1998;33:117–25.

[14] Wang G, Jacobson JA, Feng FY, et al. Sonographyof wrist ganglion cysts: variable and noncysticappearances. J Ultrasound Med 2007;26:1323–8 [quiz: 1330–1].

[15] Raza K, Lee CY, Pilling D, et al. Ultrasound guid-ance allows accurate needle placement and aspi-ration from small joints in patients with earlyinflammatory arthritis. Rheumatology (Oxford)2003;42:976–9.

[16] Balint PV, Kane D, Hunter J, et al. Ultrasound-guided versus conventional joint and soft tissuefluid aspiration in rheumatology practice: a pilotstudy. J Rheumatol 2002;29:2209–13.

[17] Chan YL, Cheng JC, Metreweli C. Sonographicevaluation of hip effusion in children. Improvedvisualization with the hip in extension and ab-duction. Acta Radiol 1997;38:867–9.

[18] Shiv VK, Jain AK, Taneja K, et al. Sonography ofhip joint in infective arthritis. Can Assoc Radiol J1990;41:76–8.

[19] Eisler T, Svensson O, Engstrom CF, et al. Ultra-sound for diagnosis of infection in revision totalhip arthroplasty. J Arthroplasty 2001;16:1010–7.

[20] Weybright PN, Jacobson JA, Murry KH, et al.Limited effectiveness of sonography in revealinghip joint effusion: preliminary results in 21 adultpatients with native and postoperative hips. AJRAm J Roentgenol 2003;181:215–8.

[21] van Holsbeeck MT, Eyler WR, Sherman LS, et al.Detection of infection in loosened hip prosthe-ses: efficacy of sonography. AJR Am J Roentgenol1994;163:381–4.

[22] Kane D, Balint PV, Sturrock RD. Ultrasonogra-phy is superior to clinical examination in the de-tection and localization of knee joint effusion inrheumatoid arthritis. J Rheumatol 2003;30:966–71.

[23] Macmahon PJ, Brennan DD, Duke D, et al.Ultrasound-guided percutaneous drainage ofmeniscal cysts: preliminary clinical experience.Clin Radiol 2007;62:683–7.

[24] DeFriend DE, Schranz PJ, Silver DA. Ultrasound-guided aspiration of posterior cruciate ligamentganglion cysts. Skeletal Radiol 2001;30:411–4.

[25] Ward EE, Jacobson JA, Fessell DP, et al. Sono-graphic detection of Baker’s cysts: comparison


with MR imaging. AJR Am J Roentgenol 2001;176:373–80.

[26] Nazarian LN, Rawool NM, Martin CE, et al. Sy-novial fluid in the hindfoot and ankle: detectionof amount and distribution with US. Radiology1995;197:275–8.

[27] Breidahl WH, Adler RS. Ultrasound-guided injec-tion of ganglia with coricosteroids. SkeletalRadiol 1996;25:635–8.

[28] Sofka CM, Adler RS. Ultrasound-guided inter-ventions in the foot and ankle. Semin Musculos-kelet Radiol 2002;6:163–8.

[29] Femino JE, Jacobson JA, Craig CL, et al. Dynamicultrasound of the foot and ankle: adult and pedi-atric applications. Techniques in Foot and AnkleSurgery 2007;6:50–61.

[30] Flanum ME, Keene JS, Blankenbaker DG, et al.Arthroscopic treatment of the painful internalsnapping hip: results of a new endoscopic tech-nique and imaging protocol. Am J Sports Med2007;35:770–9.

[31] Tsai WC, Hsu CC, Chen CP, et al. Plantar fasciitistreated with local steroid injection: comparisonbetween sonographic and palpation guidance.J Clin Ultrasound 2006;34:12–6.

[32] Farin PU, Rasanen H, Jaroma H, et al. Rotatorcuff calcifications: treatment with ultrasound-guided percutaneous needle aspiration andlavage. Skeletal Radiol 1996;25:551–4.

[33] Aina R, Cardinal E, Bureau NJ, et al. Calcificshoulder tendinitis: treatment with modifiedUS-guided fine-needle technique. Radiology2001;221:455–61.

[34] Krasny C, Enenkel M, Aigner N, et al. Ultra-sound-guided needling combined with shockwave therapy for the treatment of calcifying ten-donitis of the shoulder. J Bone Joint Surg Br2005;87:501–7.

[35] McShane JM, Nazarian LN, Harwood MI. Sono-graphically guided percutaneous needle tenotomyfor treatment of common extensor tendonosisin the elbow. J Ultrasound Med 2006;25:1281–9.

[36] Testa V, Capasso G, Benazzo F, et al. Manage-ment of Achilles tendinopathy by ultrasound-guided percutaneous tenotomy. Med Sci SportsExerc 2002;34:573–80.

[37] Testa V, Capasso G, Maffulli N, et al. Ultrasound-guided percutaneous longitudinal tenotomy forthe management of patellar tendinopathy. MedSci Sports Exerc 1999;31:1509–15.

[38] Torriani M, Etchebehere M, Amstalden E. Sono-graphically guided core needle biopsy of boneand soft tissue tumors. J Ultrasound Med 2002;21:275–81.

[39] Lopez JI, Del Cura JL, Zabala R, et al. Usefulnessand limitations of ultrasound-guided corebiopsy in the diagnosis of musculoskeletaltumours. APMIS 2005;113:353–60.

[40] Barth RJ Jr, Merino MJ, Solomon D, et al.A prospective study of the value of core needle bi-opsy and fine needle aspiration in the diagnosis ofsoft tissue masses. Surgery 1992;112:536–43.

[41] Ball AB, Fisher C, Pittam M, et al. Diagnosis ofsoft tissue tumours by Tru-Cut biopsy. Br J Surg1990;77:756–8.

[42] Mankin HJ, Mankin CJ, Simon MA. The hazardsof the biopsy, revisited. Members of the Muscu-loskeletal Tumor Society. J Bone Joint Surg Am1996;78:656–63.

[43] Welker JA, Henshaw RM, Jelinek J, et al. The per-cutaneous needle biopsy is safe and recommen-ded in the diagnosis of musculoskeletal masses.Cancer 2000;89:2677–86.

[44] Yao L, Nelson SD, Seeger LL, et al. Primarymusculoskeletal neoplasms: effectiveness ofcore needle biopsy. Radiology 1999;212:682–6.

musculoskeletal ultrasound 2007 vol.2 issues 4 2008-05-16 1416043756 jon a. jacobson saunders

Documents