wrist imaging by venkatesh m
DESCRIPTION
TRANSCRIPT
IMAGING OF WRIST JOINT
SPEAKER-Dr M VenkateshMODERATOR-Dr.Anusha S
Anatomy of the wrist
Distal portions of the radius and ulna, the proximal and distal rows of carpal bones,and the bases of the metacarpals .
The proximal row of carpal bones consists of the scaphoid, lunate, triquetrum, and pisiform.
The distal row of carpal bones contains the trapezium, trapezoid, capitate, and hamate bones.
The proximal carpal row is termed an intercalated segment because forces acting on its proximal and distal articulations determine its position.
This aspect of the osseus anatomy becomes important when considering the pattern ofcollapse that occurs in the different types of wrist instability.
3joints- do not communicate with one another
Distal radio-ulnar, radiocarpal and midcarpal joints
Wrist flexion and extension - half at radiocarpal joint and half at the midcarpal joint,
Radial and ulnar deviation - midcarpal joint
DRUJ compartment
Pivot type of synovial joint. Responsible for pronation and supination.TFC Connects ulna and radius at their distal
edges Separates DRUJ from radio-carpal joint. Arises from the ulnar aspect of the
lunate fossa of the radius and inserts in the fovea at the base of the ulnar styloid process
Components of TFCC Complex
Connects ulna and radius at their distal edges and separates DRUJ from radio-carpal joint.
Triangular fibrocartilage Meniscal homolog - between the ulna and
triquetrumVolar and dorsal radioulnar ligamentsUlnar collateral ligamentVolar ulnolunate and ulnotriquetral
ligamentSheath of the ECU tendon
Sagittal T1-weighted MR image. Note the thicker appearance of the volar and dorsal portions of the TFCC (arrows) on sagittal section.
The distal radioulnar joint is primarily stabilized by the TFCC. The TFC functions as a cushion between the ulnar head and carpal bones.
Many of the structures that make up the complex are connected by fibrous bands
Radio-carpal and midcarpal joints
The radiocarpal joint is formed proximally by the distal surface of the radius and TFC and distally by the proximal row of carpal bones
The midcarpal compartment extends between the proximal and distal carpal rows.
Lister’s tubercle on the dorsal radial ridge - site of spur.
LIGAMENTS OF WRIST
EXTRINSIC LIGAMENTS INTRINSIC LIGAMENTS
Link the carpal bones to the radius and ulna.
Connect the individual carpal bones
RADIOCARPAL ULNOCARPAL
Figure 101-3 Anatomy of the volar ligaments. A, Diagram illustrating the volar radiocarpal and ulnocarpal ligaments. B, Correlative coronal MR arthrogram image. RLT, radiolunotriquetral ligament; RS, radioscaphoid (radioscapholunate) ligament; RSC, radioscaphocapitate ligament; UC, ulnocarpal ligaments; UL, ulnolunate ligament; UT, ulnotriquetral ligament
Normal intercarpal ligaments. A and B, Central portion. The central portions of the intercarpal ligaments are thinner. They course along the more inferior aspect of the corresponding carpal bones as seen on the coronal MR image in A and corresponding thin coronal histologic section in B. Note the scapholunate ligament (white arrow in A, black arrow in B), and the lunotriquetral (arrowhead). The scapholunate ligament may appear triangular in this central region. Also, note on the histologic section the differing characteristics of the TFCC, with the more fibrocartilage-like articular disk (small black arrow) and the more ligament-like peripheral ulnar attaching portion (smaller arrowheads in B), see later discussion. C, Dorsal portion of the ligaments. The ligaments in this portion thicken and extend more vertically, especially the scapholunate ligament. Scapholunate ligament (arrowhead), lunotriquetral ligament (white arrow).
Extrinsic carpal ligaments
Limit motion and stabilize the proximal carpal row
Originate in forearm, insert onto carpal bones,
Classified as volar or dorsal. Volar radiocarpal ligaments are
stronger and thicker than the dorsal ligaments
Extrinsic ligaments - Volar Ligaments
Most important stabilizers of wrist motion.
Originate from the volar aspect of the styloid process of the radius.
Radioscaphocapitate ligament (RSC) connects the radius to the distal carpal row and plays an important role in preventing rotary subluxation of the scaphoid.
The second and strongest, the radiolunotriquetral (RLT) ligament, connects the radius to the proximal carpal row
Dorsal ligaments Provide stability
to wrist motion Frequently
injured in a fall on the outstretched hand, producing a "dorsal wrist sprain."
Best depicted on dorsal coronal images
Coronal MR arthrogram. The dorsal radiocarpal ligament (white arrow) is seen. More distally the dorsal intercarpal ligament is identified (black arrow).
Dorsal extrinsic ligaments of the wrist. (A, B) Coronal 3D GRE images at different levels show the dominantdorsal carpal ligaments.
CARPAL TUNNEL
Carpal tunnel or carpal canal is the passageway on the palmar side of the wrist that connects the forearm to the middle compartment of the deep plane of the palm
A total of nine flexor tendons pass through the carpal tunnel: flexor digitorum profundus (four tendons) flexor digitorum superficialis (four tendons) flexor pollicis longus (one tendon) median nerve between tendons of flexor digitorum
profundus and flexor digitorum superficialis
GUYONS CANAL
The ulnar canal or ulnar tunnel, also called Guyon's canal, is a space between flexor retinaculum and the palmar carpal ligament (which runs between the pisiform and the hamate ), through which the ulnar artery and the ulnar nerve travel into the hand.
RADIOGRAPHIC VIEWS
PA view Lateral viewScaphoid views
Postero-anterior ulnar deviation view Posterior oblique view Anterior oblique ulnar deviation view
Carpal tunnel view
PA VIEW
LATERAL VIEW
SCAPHOID-
Postero-anterior ulnar deviation view
Posterior oblique view
Anterior oblique ulnar deviation view
CARPAL TUNNEL VIEW
CLENCHED FISTVIEW
Figure 21 Normal clenched fist view. With a tight fist, the contracting tendons and muscles create a force within the wrist that drives the capitate (C) proximally toward the scapholunate joint.
In wrists with a lax or disrupted scapholunate ligament, the joint will widen.
In this case, the S-L interval did not abnormally widen.
CARPAL ARCS
The three carpal arcs: smooth curves joining the surfaces of the carpal bones -The first arc is a smooth curve outlining the proximal convexities of the scaphoid, lunate and triquetrum.-The second arc traces the distal concave surfaces of the same bones- Third arc follows the main proximal curvatures of the capitate and hamate.
GILULA”S ARCS
An arc is disrupted if it cannot be traced smoothly.
A break in one of the arcs indicates a fracture or the disruption of a ligament leading to a subluxation or dislocation
PARALLELISM
The joint spaces of the wrist have a width of 2 mm or less. Only the radiocarpal joint is slightly wider.
The carpometacarpal joints are slightly narrower than the midcarpal joints.
The capitolunate joint is considered the baseline joint width to which other joint spaces can be compared.
SYMMETRY
Carpal joints should be symmetrical. Furthermore, when viewed in profile (tangentially), the cortical margins of the bones constituting that joint should be parallel.
Bone edges that are not viewed in profile do not display this parallelism
CARPAL BONE AXIS
Drawing the longitudinal axes of some of the carpal bones on a lateral radiograph and measuring the angles between them is a good method of determining the wrist bones- spatial relationship.
The three most important axes are those through the scaphoid, the lunate and the capitate, drawn on the lateral radiograph.
SCAPHOID
The true axis of the scaphoid is the line through the midpoints of its proximal and distal poles.
Since the midpoint of the proximal pole is often difficult to appreciate, an almost parallel line can be used that is traced along the most ventral points of the proximal and distal poles of the bone
LUNATE
The axis of the lunate runs through the midpoints of the convex proximal and concave distal joint surfaces and can best be drawn by finding the perpendicular to a line joining the distal palmar and dorsal borders of the bone
Scapholunate angleNormal: 30 - 60Questionably abnormal: 60 - 80?Abnormal: > 80- This indicates instability of the wrist.
LUNATE SHAPE
The lunate has a trapezoidal shape, as thesides converge from the proximal surface tothe distal surface, which are grossly parallel.
If the lunate is tilted, it becomes triangular inshape. Awareness of this fact prevents thinkingthe lunate might be dislocated based only on itsappearance, that in fact changes with itsposition.
So it may be dislocated with tilting or just betilted.
Schematic representation of the lunate shape in different positions
CAPITATE
The capitate axis joins the midportion of the proximal convexity of the third metacarpal and that of the proximal surface of the capitate.
Capitolunate angleNormal: Abnormal: > 30- indicates instability of the wrist.
ULNAR VARIANCE
The posteroanterior view of the distal forearm reveals anatomic variations in the length of the radius and the ulna, known as ulnar variance or Hulten variance.
As a rule, the radial styloid process exceeds the length of the articular end of the ulna by 9 to 12 mm.
At the site of articulation with the lunate, however, the articular surfaces of the radius and the ulna are on the same level, yielding neutral ulnar variance
Occasionally, the ulna projects more proximally—negative ulnar variance (or ulna minus variant); or more distally—positive ulnar variance (or ulna plus variant)
Ulnar variance on PA wrist views. (A) Normal or neutral variance. Perpendicular to the long axis of the radius, tangential lines are drawn along the ulnar-most extent of the subchondralwhite line of the distal radius and the distal-most extent of the articular surface of the ulnar dome. The shortest distance between these two lines is the measure of ulnar variance. (B) Negative ulnar variance or ulna minus variance (measurement of dotted line). © Positive ulnar variance (measurement of dotted line).
RADIAL LENGTH To quantify shortening of the
distal radius Comparison with the
contralateral side is necessary Method – STEP 1 – Obtain the long axis of
the Radius & extend the line distally into the carpus
STEP 2 - Perpendicular line drawn through the radial styloid tip
STEP 3 - Another perpendicular line drawn through the distal articular process of ulna
Distance between the 2 parallel lines = Radial Length
Radial Length = 12 mm
RADIAL INCLINATION
Describes the angulation of the distal radial articular surface in the coronal plane
Important for predicting functional outcome Method – STEP 1 – Obtain the long axis of the Radius & extend
the line distally into the carpus STEP 2 - The distal tip of the radial styloid and the
ulnar aspect ofthe distal radial articular surface are joined by a second
line STEP 3 - A perpendicular from the long axis of the
radius is placed to intersect the second line. The angle between these two lines is the Radial inclination
Normal Radial Inclination = 16° - 28° (Mean = 22°)
CARPAL HEIGHT
Carpal height is the distance between the base of the third metacarpal and the distal radial articular surface as determined on aPA radiograph of the wrist
--Measurement of carpal height allows comparative quantification of carpal collapse in an individual patient over time.
-- The carpal height ratio allows comparisonbetween individuals and it is the carpal height divided by the length of the third metacarpal.
Parameter Mean Value Range
Carpal Height Ratio
0.54 ± 0.03
Alternate Carpal Height Ratio
1.57 ± 0.05
Ulnar Variance
1 – 2 mm 0 – 2 mm
Radial Inclination
22 ° 16° – 28 °
Radial Length 12 mm 10 – 18 mm
Palmar Tilt 11° 11° – 45°
RadiographicEvaluation of Soft Tissues
There are two deep fat planes that are useful in the radiographic evaluation of wrist trauma: the pronator quadratus fat pad and the scaphoid fat pad.
The pronator quadratus fat pad lies between the pronator quadratus muscle and the volar tendon sheaths. It is seen on the lateral radiograph of the wrist as a linear or crescentshaped lucency just anterior to the distal radius and ulna.
The pronator quadratus fat pad. The pronator quadratus fat stripe is seen on the lateral radiograph of the wrist as a linear or crescent-shaped lucency just anterior to the distal radius and ulna (arrowheads). Fractures involving the distal radius or ulna often show volar displacement (arrows), blurring, irregularity, or obliteration of this fat plane
The scaphoid fat plane or fat stripe is a triangular or linear collection of fat that is bounded by tendons of the abductor pollicis longus and the extensor pollicis brevis and by the radial collateral ligament.
This fat plane is seen on the PA radiograph as a lucent stripe extending from the radial styloid to the trapezium and almostparalleling the radial aspect of the scaphoid
Scaphoid fat stripe. (A) The normal fat stripe is seen parallelingthe lateral aspect of the scaphoid (arrows).
(B) A non-displaced fracture of the scaphoid is associated with obliteration of the fat stripe (circle).
USG-HIGH FREQUENCY PROBE
Tendons Joints Bursae Peripheral nerves Muscles Vessels
Tendon: hyperechoic, fibrillar Muscle: relatively hypoechoic Bone cortex: hyperechoic,
shadowing Fluid: anechoic, posterior
enhancement Nerve: hypoechoic nerve
fascicles,hyperechoic connective tissue, speckled appearance
WRIST NORMAL USG ANATOMY
The long flexor and extensor tendons,many of the major ligaments, and the retinaculaof the wrist and hand can be assessed with sonography.
At sonography, peripheral nerves are depicted as multiple parallel hypoechoic areas (groups of fascicles) surrounded by echogenic perineurium and/or epineurium
Normal sonographic appearance of tendons in the wrist. (a) Longitudinal sonogram of the flexor surface of the wrist depicts the flexor digitorum superficialis (FDS) tendon at its junction with the muscle. Note the typical linear fibrillar appearance of the tendon. (b) Transverse sonogram at the same level as a shows the musculotendinous junctions of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP). The tendons appear as hypoechoic fibrils in echogenic fascicles surrounded by an echogenic epitendineum.
Transverse sonogram shows the extensor surface of the wrist at the level of the distal carpal row, with a normal small volume of anechoic synovial fluid in the tendon sheath between the extensor tendons.
Normal sonographic appearance of nerves. (a) Transverse sonogram of the median nerve in the distal forearm shows multiple hypoechoic groups of fascicles surrounded by the echogenic perineurium and epineurium, as well as an unusually prominent but normal median artery.
(b) Longitudinal sonogram of the median nerve shows parallel hypoechoic groups of nerve fasciclesand the median nerve, which lies deep to the flexor digitorum superficialis (FDS) muscle in the distal forearm.
Intrinsic Ligaments of the Wrist
2 most important are ;1. Scapholunate 2. Lunatotriquetral ligaments. Disruption of these may result in
pain, instability, and carpal dissociation.
Injury to the triangular fibrocartilage may occur in association with injuries to these ligaments
Scapholunate andLunatotriquetral Ligaments
Forearm is placed prone Wrist is positioned over a volar-placed pad
or rolled towel to achieve slight flexion Scapholunate ligament on transverse
sonograms - compact triangular echogenic fibrillar structure between lunate and scaphoid, just distal to the Lister tubercle
Absence of a sonographically detectable ligament does not necessarily indicate injury
Scapholunate andLunatotriquetral Ligaments
With the wrist in the same position, the dorsal lunatotriquetral ligament can be located by passing the transducer slightly to the ulnar side.
Appears as a compact echogenic fibrillar structure between the lunate and triquetrum
(11) Transverse sonogram shows the dorsal aspect of the proximal carpal row, just distal to the level of the Lister tubercle. Note the echogenic fibrillar appearance of the dorsal scapholunate ligament, which underlies the extensor digitorum (ED) tendons. (12) Transverse sonogram at the same level as 11 but on the ulnar side of the dorsal carpus shows the echogenic dorsal aspect of the lunatotriquetral ligament and, above it, the extensor digiti minimi (EDM) tendon.
Normal sonographic appearances of the carpal tunnel. (a) Transverse sonogram over the carpal tunnel shows the hypoechoic flexor retinaculum (arrowheads) with the median nerve immediately beneath it.The long flexor tendons of flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) are located deep to the nerve. Note the presence of a normal variant median artery (curved arrow) alongside the median nerve. (b) Extended-field-of-view transverse sonogram of the carpal tunnel shows the bones that mark its boundaries.
Transverse sonogram of the Guyon canal, obtained by using the linear-array transducer in sector mode for a wider field of view, shows the presence of a normal variant accessory muscle that may be associated with compression of the adjacent ulnar nerve.
Sonographic examination of the ulnar surface of the wrist. (a) Photograph shows the correct position of the transducer. (b) Longitudinalsonogram shows the echogenic triangular fibrocartilage deep to the extensor carpi ulnaris (ECU) tendon.
Extensor Tendons
Extensor retinaculum - strong fibrous band that extends obliquely across the dorsum of the wrist.
Has deep attachments along its course which divide its surface into six separate compartments numbered from radial (I) to ulnar (VI)
Each tunnel contains a single synovial sheath that surrounds one or more extensor tendons.
Relationships of the 6compartments of the extensor tendons (I−VI) with the Lister tubercle (arrow).
Anatomic snuff-box
Radial boundary by tendons of 1st compartment
Ulnar boundary by EPL Proximally by the radial styloid, and
distally by the base of the thumb metacarpal.
Floor is formed by the scaphoid proximally and the trapezium distally.
It contains the radial artery and cephalic vein.
The extensor pollicis longus tendon (III) crosses the tendons of the 2nd compartment to reach the thumb. The anatomic snuff-box (arrow) is a triangular space delimited by the tendons of the 1st and 3rd compartments.
Median Nerve
Lies within the carpal tunnel Located immediately beneath the retinaculum,
just to the radial side of the superficial row of flexor digitorum tendons
Rigid boundaries Increase in volume of contents or decrease in size of tunnel
symptoms. On transverse sonograms, the nerve appears
elliptic in outline and seems to become progressively flatter as it passes through the canal.
Transverse sonogram of the volar wrist shows the median nerve (blue shade) and the multiple flexor tendons (yellow shade) of the normal carpal tunnel. Transverse sonogram of the volar wrist shows the median nerve (blue shade) and the multiple flexor tendons (yellow shade) of the normal carpal tunnel.
Transverse sonogram of the volar wrist shows the median nerve (blue shade) and the multiple flexor tendons (yellow shade) of the normal carpal tunnel.
Longitudinal sonogram of the volar wrist shows the median nerve (blue shade) and the flexor tendons (yellow shade) of the normal carpal tunnel.
Longitudinal sonogram of the volar wrist shows the median nerve (blue shade) and the flexor tendons (yellow shade) of the normal carpal tunnel.
The most useful bony landmarks to identify the proximal carpal tunnel are the pisiform at its ulnar side and the scaphoid at its radial side
Distal carpal tunnel - delimited by the trapezium and the hamate
ANISOTROPY EFFECT
As the ultrasound beam interacts with multiple parallel interfaces such as ligament or tendon fibers, the beams may be reflected
away from the transducer if the probe is not held exactly perpendicular to the structure.
This effect results in anisotropy artifact(ie, an apparent area of reduced echogenicity in the ligament or tendon on the acquired image)
Anisotropy artifact. Transverse sonograms of the extensor surface of the wrist show the extensor digitorum(ED) and extensor pollicis longus (EPL) tendons, clearly and without artifact on the image obtained with theprobe held exactly perpendicular to the tendons (a), but with a significant loss of echogenicity on the image obtained with the probe held at an oblique angle to the tendons (b).
Anisotropy – What to do?
Rocking the transducer backward and forward over the ligament or tendon in the longitudinal axis (also referred to as heel-toeing) helps depict the normal echogenic fibrillar pattern.
CT
CT should be performed if conventionalradiographs provide insufficient detail aboutradiocarpal articular step-off and gap displacement
Computed tomography (CT)-protocol Two- to 3-mm axial and direct coronal or
sagittal images for conventional studies. Axial images at 1- and 0.5-mm intervals for coronal and sagittal reformatting or three-dimensional reconstruction.
MRI
MR imaging has provided us with new insights into the difficult anatomy of the wrist by allowing improved visualization of the relationship of the muscles, ligaments, tendons and bone
Its multiplanar and exquisite soft tissue contrast capabilities allow for depiction of subtle osseous and soft tissue pathology.
Indications
Ligamentous pathology Avascular necrosis Abnormalities of TFCC Carpal instability Carpal tunnel syndrome Arthritis Neoplastic lesions of the wrist and hand Trauma
Protocol
Magnetic resonance imaging (MRI) Field of view: 8 to 12 cm Coil: wrist coil or flat 5-inch coil (motion
studies) Patient position: arm at side when
possible; otherwise, arm above head
Technique
Supine with arms by the side of patient
Larger patients - arm above head. Wrist in pronation with fingers
slightly flexed Long axis of distal radius & central
metacarpal axis in neutral position with thumb up.
Sequences
T1 WI in axial, coronal and sagittal planes.
FSE T2- axial and coronal.
STIR or fat sat T2 FSE axial and coronal for tenosynovitis, ganglia, carpal tunnel syndrome and neoplasms.
GRE coronal sequences for ligaments and fluid.
3D SPGR for anatomy of TFCC & intrinsic ligaments .
T1 and STIR / fat sat T2 for bones.
Anatomy of the volar ligaments. A, Diagram illustrating the volar radiocarpal and ulnocarpal ligaments. B, Correlative coronal MR arthrogram image. RLT, radiolunotriquetral ligament; RS, radioscaphoid (radioscapholunate) ligament; RSC, radioscaphocapitate ligament; UC, ulnocarpal ligaments; UL, ulnolunate ligament; UT, ulnotriquetral ligament.
IV gadolinium for synovitis, wrist masses, and in evaluating the vascularity of the scaphoid or lunate in avascular necrosis (AVN).
Kinematic wrist devices to track carpal row motion with radial and ulnar deviation of the wrist.
Direct MR arthrography
A saline / gadolinium mixture 3 to 4 mL injected into the
radiocarpal compartment. Intra-articular gadolinium distends
the joint Most efficacious method of
diagnosing ligament injuries. Fat-saturated T1-weighted images
obtained in all three imaging planes. At least one additional fat satT2 in
coronal plane
Intravenous MR arthrography Gadolinium is injected IV.
Passive or active motion to exercise the patient to create a joint effusion and to obtain an arthrographic effect
Imaging done 15 minutes after injection to enhance vascularized or inflamed tissue
Used when direct techniques are inconvenient
Coronal MR 3D T1W gradient-echo image obtained after Intravenous Injection Of A Gadolinium-based Contrast material demonstrates synovitis.
MR ARTHROGRAPHY
1. DIRECT
2. INDIRECT
After intraarticular contrast injection into the radiocarpal joint in another patient illustrates high signal contrast extending through a TFC defect into the DRUJ
WRIST JOINT COMMON PATHOLOGIES
COLLES FRACTURE
Most common injury to the wrist caused by a fall on an outstretched hand.
The classic Colles’ fracture is a transverse fracture, with or without comminution, with or without intraarticular extension, accompanied by impaction and dorsal displacement of the distal surface of the radius.
Colles’ fracture. (A) PA oblique and (B) lateral views showa metaphyseal fracture of the radius (arrows) in mild dorsal angulation with associated ulna styloid tip avulsion fracture (arrowhead
SCAPHOID FRACTURE
The scaphoid is the most commonly fractured carpal bone in adults, accounting for 70% of all carpal injuries
Scaphoid fractures may be difficult to detect and treat.
Imaging of scaphoid fractures requires AP, lateral, and scaphoid views. Displacement or obliteration of the navicular fat stripe is a useful sign for subtle fractures.
Radionuclide scans, MRI, or CT may be useful for detecting subtle fractures and evaluating complications.
Complications: delayed union (failure to unite in 3 months), nonunion, malunion, AVN (most common with proximal pole fractures), radioscaphoid impingement, and arthrosis.
(A) Locations of scaphoid fractures: 1, tubercle; 2, distal articular surface; 3, distal third; 4, waist; 5, proximal pole. (B) Oblique fracture. Shearing forces (arrows) lead to instability and displacement. (C) Transverse waist fracture is more stable.
X-ray in a 22-year-old man with acute trauma of the right wrist is suggestive of a scaphoid fracture (b) Longitudinal US obtained in the lateral direction clearly shows cortical discontinuity (c) STIR MR image obtained - diffuse high-signal-intensity alteration of the bone marrow of the scaphoid (straight arrows) and discontinuity of the cortex.
HUMPBACK DEFORMITY
Humpback deformity of the scaphoid results from angulation of the proximal and distal parts of a scaphoid in the setting of scaphoid fracture through the waist
It is important to identify as it can result in progressive collapse of the scaphoid with non-union, and even if eventual union is achieved, destabilisation of the wrist
At first, there is angulation between fragments; next, the two fragments settle or impact into each other; and finally an exostosis (curved arrow) or bony prominence (the humpback deformity) develops dorsally at the fracture site.
Avascular necrosis (AVN) of the scaphoid
Usually occurs after a fracture through the waist or proximal pole (in 30 %).
Preiser disease - Nontraumatic AVN Chronic AVN - diminished signal intensity
with all pulse sequences, with or without associated bone collapse
Gad is helpful in determining the likelihood of AVN of the proximal pole - enhancement implies vascularised vital tissue
STIR– hyperemia of distal pole marrow
T2W - Low signal intensity of the proximal pole of the scaphoid (arrows) consistent with AVN. Patient had no history of trauma, and no fracture line was evident.
T1W – Fracture line and AVN
Kienbock’s disease
AVN of lunate. Negative ulnar variance is associated Subchondral bone adjacent to the radial
articular surface is relatively avascular. Repeated trauma and compression
fractures. Transverse microfractures may be seen
pathologically to precede frank AVN. Progression to lunate collapse and proximal
migration of the capitate bone results in loss of normal carpal structure.
Frontal view of the hand and wrist demonstrates sclerosis, irregularity and collapse of the lunate (blue arrows) in Kienbock's Disease (Kienbock's Osteomalacia)
Coronal Ti-W - abnormally low signal intensity in the lunate, compression of subchondral bone, and preservationof normal articular cartilage (arrow). Represent Kienbock disease.
Early Kienbock disease may appear as slight distortion of the trabecular pattern of the lunate.
Subsequently, marrow signal intensity diminishes
Fractures of Other Carpal Bones
The triquetrum is the second most commonly injured carpal bone (3 to 4% of all carpal bone injuries)
Isolated fractures of the capitate, trapezium, and trapezoid are infrequent.
Fracture of the body of the triquetrum. (A) A conventionallateral x-ray may not show this rare type of triquetral injury. It is better diagnosed with (B), computed tomography (arrow).
SMITHS FRACTURE
Fracture of the distal radial metaphysis or epiphysis, with or without articular involvement, demonstrating palmar displacement or angulation.
BARTONS FRACTURE
Barton’s Fracture is a marginal fracture of the dorsal rim of the radius that displaces along with the carpus, producing a fracture-subluxation
A variant of the Barton’s fracture involves the palmar rim of the distal end of the radius and may be more common than its dorsal counterpart.
It is sometimes referred to as a reverse Barton’s or a palmar Barton’s fracture.
Barton’s fracture. (A) Lateral and (B) AP oblique viewsshow a marginal fracture of the dorsal rim of the radius that is displaced along with the carpus, producing a fracture-subluxation.
Reverse Barton’s fracture. (A) Lateral and (B) PA viewsdemonstrate a volar rim fracture with palmar displacement of thecarpus with the rim fragment (arrow), consistent with a fracturesubluxation pattern
BENNET”S ROLANDO”S
Fracture of the base of the thumb metacarpal. (A) A Bennett’sfracture is consistent with a two-part fracture-dislocation (circle).(B) A Rolando’s fracture is consistent with a comminuted(three-part) fracture (circle).
Stress Fracture of the Radial Epiphyseal Plate-Gymnasts wrist
In the skeletally immature, a stress reaction can develop primarily at the distal radial growth plate and to a lesser degree in the distal end of the ulna.
Gymnastics is the major cause of it The physeal plate shows irregularity,
cysticchange, and widening, consistent with a Salter–Harris type I or II injury. There may be adjacent bone fragmentation.
“Gymnast’s wrist (SH I injury).” (A) PA and (B) lateral wrist views demonstrate widening of the physis of the radius (arrows) secondary to chronic stress reaction in a gymnast.
DISTAL RADIUS FRACTURE
CARPAL INSTABILITY
Carpal instability occurs when there is symptomatic malalignment between the rows of carpal bones and between the carpal bones and the radius.
Figuratively speaking, the proximal carpal row is termed an intercalated segment because forces acting on its proximal and distal articulations determine its position.
DISI
DISI is short for dorsal intercalated segmental instability.
The intercalated segment is the proximal carpal row identified by the lunate. The term 'intercalated segment' refers to it being the part in between the proximal segment of the wrist consisting of the radius and the ulna and the distal segment, represented by the distal carpal row and the metacarpals.
VISI
Volar intercalated segmental instability or palmar flexion instability is when the lunate is tilted palmarly too much.
LUNATE AND PERILUNATE DISLOCATION
Common dislocations of the wrist are the lunate and perilunate dislocations.
The key to differentiation between both is what is centered over the radius.
If the capitate is centered over the radius and the lunate is tilted out, it is a lunate dislocation.
If however the lunate centers over the distal radius and the capitate is dorsal, we are dealing with a perilunate dislocation
LEFT: Lunate dislocation: capitate is centered over the radius and lunate is tilted out.
RIGHT: Perilunate dislocation: lunate is centered over the radius and capitate is tilted out dorsally.
Scapholunate Dissociation
Loss of mechanical linkage between scaphoid and lunate.
Usually relates to complete disruption of the scapholunate interosseous ligament (SLIL)
Frontal Conventional Radiographic Signs:
Terry Thomas Sign (AKA David Letterman sign) Increased scapholunate joint space when
compared to contralateral side Any asymmetric gap measuring greater than 5
mm is diagnostic of SLD. Scaphoid Ring Sign
A radio-dense ring seen over the distal scaphoid representing rotary subluxation and foreshortening of the scaphoid
Lateral Plain Film Signs Increased Scapholunate Angle
> 70 degrees suggestive of dorsal intercalated segment instability (DISI)
Palmar V sign Seen when scaphoid is in abnormal flexion;
normal “C”-shaped line formed by palmar margins of scaphoid and radius form an acute angle as palmar outline of scaphoid intersects outline of radial styloid, forming sharper “V”-shape
Triangular Fibrocartilage Complex Tears
Traumatic Degenerative
Younger patients Older patients
Occur near radial attachment In vascular zone near ulnar attachment
Ulnar negative variance Ulnar positive variance
Associated with ulno lunate impaction syndrome
oTears of the TFC should be suspected in patients with Ulnar-sided wrist pain and tendernessoTFCC tears also can involve instability of the DRUJ.
MRI Evaluation
Coronal T1,T2W,GRE, STIR or fat sat T2 FSE sequences.
3D SPGR sequences for radio-ulnar and ulno-carpal ligaments.
Biconcave disc - homogeneous low to intermediate signal intensity.
Imaging findings
Full-thickness defects of the TFCC
Degenerative tears of the TFC - linear band of increased signal intensity on T1W and GRE
With complete tears the signal extends to proximal and distal articular surfaces.
In partial tears signal will extend only to one articular surface, usually the proximal surface
High signal on T2W or GRE - consistent with synovial fluid trapped in the defect.
Fluid collecting in the DRUJ is an important secondary sign, but the presence of fluid signal alone is not indicative of a tear of TFCC
MR arthrography with either a radiocarpal or distal radioulnar joint injection will reveal contrast extending through and outlining the TFC defect
Triangular fibrocartilage tears. Radial-sided tears coronal 2D T2* gradient-echo image (A) and T2 FSE image with fat saturation (B) demonstrate fluid signal intensity in the radial aspect of the TFC (arrow), which extend to the radiocarpal and distal radioulnar joint (DRUJ) articular surfaces. Fluid is seen in the DRUJ.
(C) Coronal ‘‘hi-res’’ T1 FSE image after intraarticular contrast injection into the radiocarpal joint in another patient illustrates high signal contrast extending through a TFC defect into the DRUJ (black arrow).
Chronic peripheral (TFCC) synovitis. Coronal T2-weighted MR image. Marked thickening and fluid signal is seen along the ulnar attachments and ulnar aspect of the TFCC (arrows).
Carpal Tunnel Syndrome
Entrapment syndrome due to compression of median nerve at the wrist Predisposing factors Anatomic variants - narrow tunnel, presence
of the median artery, abnormal and accessory tendons and muscles
Susceptibility of the nerve to pressure - diabetes, systemic neuropathies
Systemic and endocrine disorders - Pregnancy, hypothyroidism, amyloidosis
Space-occupying lesions within the tunnel
Carpal Tunnel Syndrome - USG A normal nerve does not exclude the diagnosis Nerve appears swollen at the proximal tunnel
and flattened at the distal tunnel “Notch sign” - An abrupt nerve calibre
change at the entrance of the carpal tunnel Nerve becomes uniformly hypoechoic with loss
of the fascicular pattern - Intraneural edema or fibrosis
Hyperemic blood flow in the longitudinal perineural plexus and within intraneural branches
Long-axis 12−5 MHz US image of the median nerve showing the notch sign at a higher magnificationCorresponding schematic drawing illustrates the main nerve shape abnormalitiesin carpal tunnel disease. Note the swelling portion (arrows) of the median nerve (MN) at the distal radius, proximal to the level of compression (arrowheads) and the nerve flattening deep to the transverse carpal ligament (curved arrow)
Carpal tunnel syndrome. Median nerve (MN) appears increasingly swollen and hypoechoic (open arrows) with absent fascicular patternObserve the normal size of the nerve at the forearm (white arrowheads) between the FDS and FDP. At proximal carpal tunnel level, the notch sign (open arrowheads), indicates the compression point. More distally, at the distal carpal tunnel, the nerve remains flattened and hypoechoic (white arrows).
Width over 1.0 cm is suspect for and any measurement over 1.5 cm is consistent with Carpal Tunnel Syndrome, if suspected clinically.
Compare to the contralateral side if unilateral involvement is suspected or one side is more symptomatic than the other.
If one nerve is significantly larger than the other, regardless of measurements, this suggests inflammation
Method for calculating the bulging of the transverse carpal ligament. A line (dashed line) is drawn to join the tubercle (star) of the trapezium (Tra) and the hook (asterisk) of the hamate (Ham). Then, a perpendicular (continuous white line) to this line is drawn to reach the most prominent portion of flexor retinaculum (arrowheads). When this latter line measures 4 mm, it indicates abnormal bulging of the ligamentBowing ratio – TH line divided by perpendicular line - >0.15 suggests increased pressure / volume in tunnel
Quantitative indexes in carpal tunnel syndrome - Increased intracanal pressure may often lead to an increased convexity of the transverse carpal ligament that is normally straight or slightly convex
Besides assessing the median nerve and the transverse carpal ligament, extrinsic causes for nerve entrapment can also be identified
Most patients with carpal tunnel syndrome are affected by tenosynovitis of flexor tendons
A variety of SOLs can be encountered within the carpal tunnel.
Carpal tunnel syndrome in tenosynovitis of the flexor tendonsLong-axis US image of the median nerve at the distal radiusdemonstrates abnormally increased fluid effusion (asterisks) surrounding flexor tendons (ft), resulting in palmar displacementand compression of the median nerve (MN) at the entrance of the tunnel
Long-axis colour Doppler US image of the median nerve (MN) demonstrates blood flow signals (arrowheads) from the longitudinal perineural plexus and the intranervous branches as a result of hyperemic changes relatedwith the inflammation
Carpal tunnel syndrome. Sagittal US scans show swelling of the proximal portion of the median nerve (arrows) in the right wrist (RT) in a 45-year-old woman. Color Doppler US shows increased vascularity in the swollen part of the nerve. Compare with the normal median nerve (arrowheads) in the left wrist (LT).
Palm ganglion with median nerve compression. Transverse US scan of the median nerve at wrist level shows an anechoic ganglion (arrows) compressing the median nerve (arrowheads) in a 60-year-old man.
Carpal tunnel syndrome in a 52-year-old man with rheumatoid arthritis. Longitudinal (a) and transverse (b) 10-13-MHz US images obtained at the distal radius show abnormally increased effusion (*) surrounding the flexor tendons (FT), resulting in palmar displacement and compression of the median nerve (MN) at the entrance to the tunnel (arrow).
MRI
Changes seen in median nerve- Median nerve shape – flattening , swelling ,
deformed Diffuse swelling or segmental
enlargement. Increased signal intensity in median nerve
in T2* or STIR sequences - Due to oedema or demyelination
Palmar bowing of flexor retinaculum. Deep palmar bursitis Tenosynovitis Soft tissue masses
Post gad- Enhancement due to nerve edema or lack of enhancement due to ischemia.
Tenosynovitis Bowing of retinaculum – Bowing ratio Inflamed synovium and tendon sheaths
are hypo on T1 and hyper on T2 and STIR sequences.
(a) Axial T2-weighted MR image proximal to the transverse carpal ligament demonstrates enlargement of and increased signal intensity within the median nerve (arrow). R = radial aspect.
(b) Axial T2- W MR image obtained more distally in a patient with symptoms of CTS demonstrates relative flattening of the median nerve (arrow).relative flattening at the level
Ulnar tunnel syndrome
Entrapment of ulnar nerve in Guyon’s canal
Causes : fracture or mass lesions.
Axial T1, T2 images.
Normal nerve- low signal.
Guyon tunnel syndrome. Transverse (left) and sagittal (top right) US scans show a well-defined hypoechoic nodule (arrowheads) in the wrist, compressing the ulnar nerve (arrows) in a 48-year-old man in whom leiomyoma was diagnosed. Color Doppler image (bottom left) shows the ulnar nerve (A) located between the tumor and ulnar artery.
Guyon tunnel syndrome: ganglion. Transverse US scans of the wrist show an anechoic ganglion (G) compressing the ulnar nerve (arrowheads) at wrist level. The ulnar nerve is located between the ulnar artery and ganglion.
ULNAR LUNATE ABUTMENT SYNDROME
Ulnar lunate abutment syndrome is associated with ulnar positive variance (Fig. 9-55).
Ulnar wrist pain that often is exaggerated by ulnar deviation of the wrist.
Radiographs show ulnar positive variance and sclerosis or cystic change in the lunate and triquetrum.
Features are more easily demonstrated with MRI for early bone, cartilage, and triangular fibrocartilage abnormalities.
PA radiograph demonstrates ulnar positive variance (line), prominent ulnar styloid, and sclerotic changes in the lunate and triquetrum caused by cartilage loss (open arrows).
(A) T1-weighted image shows low signal intensity in the lunate and adjacent triquetrum. (B) Gradient echo coronal shows displacement of the radial aspect of the triangular fibrocartilage (open arrow) and a peripheral tear (black arrow).
DEQUERVAINS TENOSYNOVITIS
De Quervain tenosynovitis involves the first dorsal extensor compartment.
Patients present with pain and restriction of the extensor pollicis brevis and abductor pollicis longus.
The condition is most common in women 30 to 50 years of age
MRI or ultrasound may be used to confirm the diagnosis. The region of the radial styloid may have abnormal signal intensity as the result of chronic tendon thickening
Thickening of tendon sheath of abductor pollicis longus tendon and extensor pollicis brevis tendon.
Increased vascularity.
De Quervain tenosynovitis. Coronal fast spin-echo fat-suppressed T2-weighted image demonstrates marrow edema in the radial styloid and thickening (arrow) of the adjacent tendons
CPPD ARTHROPATHY
Resulting from the intraarticular presence of calcium pyrophosphate dihydrate (CPPD) crystals.
The condition may be asymptomatic, in which case the only radiologic finding may be chondrocalcinosis .
Characterized by calcification of the articular cartilage and fibrocartilage; the tendons, ligaments, and joint capsule may exhibit calcifications as well
A dorsovolar radiograph shows chondrocalcinosis of the triangular fibrocartilage, cystic changes in the scaphoid and lunate, and narrowing of the radiocarpal joint.
Rheumatoid Arthritis
Synovitis - increased synovial vascularity and volume
Joint effusions. US - thickened,
hypoechoic, intra-articular tissue that is poorly compressible
Dorsal wrist - noncompressible hypoechogenicity, likely representing a distended jointcapsule (arrowheads) , synovial hyperemia
Rheumatoid Arthritis
Increased signal on fluid-sensitive sequences in areas invested by synovium.
Advanced stages - synovium becomes hypertrophied beginning at bare areas of the joint
Bare area - Intra-articular cortical bone within the joint capsule, lined by synovium but devoid of hyaline articular cartilage.
Rheumatoid Arthritis
An inflammatory pannus - increased signal on fluid-sensitive sequences - difficult to differentiate from effusion
Enhancement of the synovium occurs rapidly between 60 and 120 seconds
After this period, equilibrium occurs between the synovium and the effusion in which the Gd diffuses from the synovium into the articular space
(A) Coronal T1-W - Heterogeneous low-signal intensity within the scaphoid and lunate. heterogeneous low signal in the distal radioulnar joint and ulna styloid recess in a patient with RA. (black arrowheads). (B) Coronal fat-suppressed T1W post contrast - Pannus enhancement in the ulna styloid recess and distal radioulnar joint in a patient with RA (white arrowheads). Note the erosions of the waist of the triquetral bone. A subchondral cystis noted at the base of the lunate.
Gout
(A)Axial T2-W - large tophus displacing the extensor carpi ulnaris tendon dorsally (arrowheads).
(B)Coronal T1-W - gouty tophus (doublearrowheads) and thick inflamed synovium along the extensor carpi ulnaris tendon sheath (arrowhead).
Ganglion
Cystic swelling overlying a joint or tendon sheath with/without septations
Secondary to the protrusion of encapsulated synovial tissue.
Extending toward the adjacent joint. Usually symptomatic, due to increased
ligamentous pressure or compressed nerve More on dorsal side (70%), scapholunate
region MRI and US: equally effect in detection US: initial imaging procedure due to dynamic
capabilities, lower cost.
ganglion in dorsal wrist with point to the radio-carpal joint. US image -an echo-free cyst (arrows) in dorsal wrist.
MRI
Well demarcated. Edema or inflitration of the adjacent
tissues is rare. Low on T1 and high on T2. May be loculated with fibrous
septations.
Subperiosteal ganglion. a (arrowheads) arising from the periosteum of the ulna and gradually sinking into the ulnar head (curved arrow) as a result of the pressure absorption of the bone below the enlarging cyst.Note the extensor carpi ulnaris tendon (straight arrow) displaced and compressed between the ganglion and the retinaculum.b Oblique radiographic view and c transverse T2w tSE MR imaging correlation confi rm a deep bone erosion (curved arrow) in the ulnar head.
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INTERSECTION SYNDROME Intersection syndrome occurs slightly
proximal to de Quervain tenosynovitis . A bursa may form between the
extensor carpi radialis longus and brevis and the abductor pollicis longus and extensor pollicis brevis.
Patients with intersection syndrome are frequently involved in racket sports and present with pain, weak grip, and crepitation (squeaker's wrist).
Axial fat-suppressed T2-weighted image demonstrating a fluid-filled bursa (arrow).