investigations in orthopedics

8/8/2019 Investigations in Orthopedics

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ImagingPlain film radiography

y The radiographic image are produced by the

accentuation of x- rays as they pass throughintervening tissues before striking plate or film.

y The more dense and impermeable the tissues, thegreater the accentuation and therefore the more blank.

Or white.


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y Metal implant appears intensely white , bone less soand soft tissues in varying shades of grey.

y Cartilage appears as a dark area between the adjacentbone ends

y One bone overlying another produces superimposedimages .

yAny abnormality seen in the resulting combined imagecould be in either bone , so it is important to obtainseveral image from different projections in order toseparate the anatomical outlines.


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yA convenient sequence for examination is

1. Patient

2. Soft tissues3. Bone

4. Joint

5. Cartilage

6. Diagnostic associations


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patienty Name

yAge

y Sexy Clinical details

y Similarly, when requesting an x-ray examination , givethe radiologist enough information to indicate yourline of thinking.


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The soft tissuesShape

y Muscle planes are often visible and may reveal wasting

or swelling .y Bulging outlines around the hip may suggest a joint

effusion .

y Soft tissue swelling around interphalengeal joints may

be the sign of rheumatiod arthritis.


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Density

y Increased density in the soft tissues follows

calcification in a tendon , blood vessel, a haematoma ,or an abscess .

y The radiographic density of a metallic foreign body isusually unmistakable.

y Decreased density of soft tissues is due either to fat orto gas


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The bonesShape

y Look at overall shape and how they fit together.

y Identify the anatomical structures and study eachcarefully.

for the spine, look at the overall vertebral alignment,then at the disc spaces, and then at each vertebra

separately, moving from the body to the pedicles, thefacet joints and finally to the spinous appendages.


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For pelvis, see if the shape is symmetrical with thebones in their normal positions, then look at the

sacrum, the two innominate bones , the pubic ramiand the ischial tuberosities , then the femoral headsand the upper ends of the femora.

Always comparing both sides


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y The bone may be bent as in Pagets disease.

yA localized deformity or swelling may be due to

bulging from within or to excessive new boneformation.

y Examine the periosteal surface , the cortex , and theendosteum .


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Density

y Note whether the density is increased( sclerosis) or

decreased( osteoporosis or abnormal bone tissues)y The trabecular structure is usually visible .

Is it regular?

Is it disarranged ?

Or absent


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y Focal defects with sharp margins are usually benign.

y Defect with fuzzy margins may signify infection or a

malignant lesion.y Moth eaten appearance indicates malignant.

y The site of lesion is important.

Bone cyst occur in the metaphysis

Giant cell tumor always at the very ends of the bone


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The jointShape

y General orientation of the joint and the congruity of

the bone ends.y Look for narrowing or asymmetry of the joint space

which could signify loss of articular cartilagethickness( athritis)

y Interruption of the subarticular bone plates indicatejoint destruction.

y Bony outgrowth from the joint margins are typical ofosteoarthritis


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Density

y Lines of increased density within the articular space

may be due to calcification of the cartilage or menisci(chondrocalcinosis)


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Diagnostic associationsy Narrowing of the joint space+ subarticular cysts +

osteophytes= osteoarthritis

yNarrowing of joint space + osteoporosis + periarticularerosion = inflammatory arthritis

y Bone destruction+periosteal bone formation=infection or malignancy until proven otherwise


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X-rays using contrast mediay Iodine based liquids is commonly used and is

injected into sinuses, joint cavities, or the spinal theca.

y

Air or gas can be injected to produce negative imageoutlining the joint cavity.

y Oily iodides are non-miscible and do not penetratewell into all the nooks and crannies.

y Metrizamide is a non ionic iodide , is the least toxicand least irritant.


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Sinographyy The simplest form.

y The medium is injected into an open sinus.

y The film shows the track and whether or not it leads tothe underlying bone or joint.


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Arthrographyy Intra-articular loose bodies will produce filling defects

in the opaque contrast medium .

y

In childrens hips, arthrography is useful in outliningthe cartilaginous and femoral head.

yArthrography may show up torn flaps of cartilage inavascular necrosis.

y In the ankle or wrist , extrusion of injected contrastmedium may disclose tears in the capsular structures.


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Myelographyy Used to diagnose disc prolapse and spinal canal

lesions.

y

Replaced by CT orMRI.y However , it is indicated for cervical root lesions.

y The oily media are no longer used.

y Metrizamide is used .

yA bulging disc, an intrathecal tumour producedistortion of opaque column in the myelogram.


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Tomographyy It provides an image focused on a selected plane and

may show changes that are obsecured by the

overlapping image in conventional x-ray.y Useful for detecting changes in the spine.


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Computed tomography( CT )y Useful for showing detailed fracture patterns, for

displaying the shape of the spinal canal and for

mapping the spread of tumours into soft tissues.y The computed data can be reconstructed as a 3D

image.

y Disadvantage= high radiation exposure.


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Radionuclide scanningy 9m technetium diphosphate is injected intravenously

and its presence is recorded with gamma camera or

rectilinear scanner.y Increased uptake during blood phase signifies a

hyperemia.

yActivity during bone phase suggests new bone

formation.y Useful to diagnose stress fractures , bone infection,

and bone tumours.


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MRIy Bone tumor can be displayed in their transverse and

longitudinal extent ,and extraosseous can be assessed.

y

It is useful is diagnosing bone ischemia , and necrosis ,the investigation of backache and spinal disorder, andthe elucidation of cartilage and ligament injuries.

yAlso useful to diagnose rotator cuff tears and labral

injuries in the shoulder and ligament injuries aroundthe ankle.


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Diagnostic ultrasoundy High frequency sound waves generated by transducer, can

penetrate soft tissue and some reflected back to thetransducer where they are registered as electrical signal and

displayed as images on a screen .y Real time display gives a dynamic images which is more

useful than usual static images on transparent plates.

y It is simple and portable.

y Useful in identifying hidden cystic lesion such ashematoma, abscess and popliteal cyst.

y Also useful in screening newborn babies for developmentaldysplasia of hip.


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electrophysiologicalMotor nerve conduction

y The time interval between stimulation of a motor

nerve and muscle contraction can be measuredaccurately .

y If the test is repeated at two points a fixed distanceapart along the nerve, the conduction velocity can be

determined.y Normal values are 40-60 m/s


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y Conduction velocity is reduced in peripheral nervedamage or compression.

y The site of lesion can be established by takingmeasurements in different segments of the nerve.

y If the nerve is divided , there is no response tostimulation of the nerve and an abnormal response to

galvanic stimulation of the muscle- reaction ofdegeneration.


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Electromyography

yAn electrode is used to record motor unit activity at

rest and during attempts to contract the muscle.y Normally there is no electrical activity at rest, but on

voluntary contraction , characteristic oscilloscopicpatterns appear.

y Changes in these patterns can be identify certainneuropathic and myopathic disorder.

yAfter nerve injury, there will be denervation potentialsand recovery equally typical re-nervation potential.


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Biochemical testsNon specific blood tests

y Hypochromic anemia

Usual in rheumatoid arthritis(RA)

y Leucocytosis

Associated with infection.

Mild leucocytosis is common in RA and during attackof gout.


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The erythrocyte sedimentation rate(ESR)

Increased in acute and chronic inflammatory

disorders and tissue injury.ESR is affected by presence of monoclonal

immunoglobulin.

High ESR is mandatory in diagnosis of myelomatosis.


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C-reactive protein (CRP)

Increased in chronic inflammatory arthritis.

Used to monitor the progress and activity ofrheumatoid arthritis.

Plasma gamma-globulin

Helpful is assessment of rheumatoid disorders , and inthe diagnosis of myelomatosis.


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Rheumatoid factor testsy Rheumatoid factor is an autoantibody which is often

present in patients with RA

y

It is not diagnostic and some patient will remainseronegative.

y It is absent in patients with ankylosing spondylitis ,reiters disease or psoariatic arthritis.


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Tissue typingy HLA antigens can be detected in WBC and they are

used to characterize individual tissue type.

y

Seronegative spondarthritides are associated withHLA-B27 on chromosome 6.

y This is used as confirmatory test in patient havingankylosing spondyarthritis or Reiters disease.


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Biochemical tests for metabolic

bone diseasesSerum calcium and phosphatey Should be measured in the fasting state and it is the

ionized calcium fraction that is important.

Serum alkaline phosphatase concentration

y Index of osteoblastic activity.

y It is raised in osteomalacia , and high bone turn over (hyperparathyroidism , Pagets disease , bonemetastases)


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Parathyroid hormone activity

y Can be estimated from serum assays of the COOH

terminal fragment.y But in renal failure, it is unreliable because there is

reduced clearance of COOH fragment

Vitamin D activityyAssess by measuring the serum 25-HCC concentration.


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Urinary calcium and phosphate

y Significant alterations are found in

hyperparathyroidism and malabsorption disorder.

Urinary hydroxyproline excretion

y It is a measure of bone resorption.

y Increased in high-turnover conditions like Pagetsdisease.


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Excretion of pyridinium compounds and telopeptides

y Sensitive index of bone resorption .

y Useful in monitoring the progress of osteoporosis andhyperparathyroidism.


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rehabilitationy rehabilitation is recognized as an important part of the

acute-care program.

y

It involves correcting limb deformities, increasingmuscle strength, maximizing motor control, trainingindividuals to make the most effective use of residualfunction, and providing adaptive equipment.


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Management ofCommon

Problems in Rehabilitationy Inadequate nutrition

y decubitus ulcers

y urinary tract infectionsy impaired bladder control

y spasticity

y contractures

y acquired musculoskeletal deformities

y muscle weakness

y physiologic deconditioning


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Inadequate Nutritiony In trauma patients, the nutritional requirements are

markedly increased from the normal maintenancerequirement of 30 kcal/kg/day.

y Most trauma patients have been receiving intravenousfluids with minimal nutritional benefit and so arrive atthe rehabilitation center in various degrees ofmalnutrition.

yPhysically handicapped people expend much of theirenergy performing simple activities of daily living(ADLs) and may also have difficulty in obtaining andpreparing adequate amounts of food.


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Decubitus Ulcers (Pressure Sores)y The combination of poor nutritional status, lack of

sensation at pressure points of the body, anddecreased ability to move can cause decubitus ulcers.

y The ulcer is a potential source of sepsis in an alreadycompromised individual and often requires that a flapgraft be rotated to cover the defect.

yAfter a sacral flap is rotated, the patient must remain

in a prone position until the graft heals.y The clinical rule of protecting the patient's skin is to

change position every 2 hours. No cushion cancompletely prevent decubitus ulcers.


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Urinary Tract Infections and

Impaired BladderControly In an acutely ill or multiply injured patient, an

indwelling catheter may be necessary for medicalreasons but should be removed as soon as possible.

y In male patients, incontinence can be managed with acarefully applied condom catheter.

y Restoring bladder function to achieve adequate reflex

voiding or a balanced bladder may require the use ofan intermittent catheterization program.


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Muscle Weakness and Physiologic

Deconditioningy A physical conditioning program can increase the aerobic

capacity by improving cardiac output, increasinghemoglobin levels, enhancing the capacity of cells to

extract oxygen from the blood, and increasing the musclemass by hypertrophy.

y Prolonged immobilization of extremities, bed rest, andinactivity lead to pronounced muscle wasting andphysiologic deconditioning in a short period of time.

y Because disabled patients generally expend more energythan normal individuals in performing the routine ADLs,they must be mobilized as quickly as possible to preventunnecessary physiologic decline.


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Spasticityy Spasticity must be managed aggressively to prevent

permanent deformities and joint contractures.

y

Spasmolytic Drugsy Drugs can be of some assistance in controlling

spasticity associated with upper motor neurondiseases. Drugs are used when spasticity affects

multiple large muscle groups in the body and whenthe spasticity is not severe.

Baclofen (Lioresal)

Dantrolene (Dantrium)


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y Casts

Casting temporarily reduces muscle tone and is

frequently used to correct a contracture.

If a cast must be used for a prolonged period, thepatient should be placed on anticoagulant therapy to

prevent deep venous thrombosis.


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y Splints

Anterior and posterior clamshell splints can be used to

control joint position and still allow for active andpassive range of motion (ROM) of the joints intherapy.


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Joint Contracturesy Inactivity and uncontrolled spasticity often lead to joint

contractures which are difficult to correct and greatlyextend the needed rehabilitation program.

y

To prevent contractures, exercises to maintain ROM mustbe performed several times daily. The patient, familymembers, therapists, and nursing personnel should allparticipate in this task.

y In general, if a contracture is present for less than 3months, it may be amenable to nonsurgical methods of

correction such as serial casting or electrical stimulation ofthe antagonist muscles.

y When the desired limb position is obtained, a holding castis used to maintain the position for an additional week.


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Use of Orthosesy Orthotic (brace) prescription plays a vital role in

rehabilitation.y A temporary orthosis may be used in an early stage of

illness until a definitive, custom-fitted orthosis isfabricated.y Definitive orthoses for the lower extremity are the below-

knee ankle-foot orthosis (AFO) and the above-knee knee-ankle-foot orthosis (KAFO).

y The bichannel adjustable ankle-locking (BiCAAL) type ofAFO is commonly applied as the first orthosis followingstroke, head trauma, spinal injury, or other condition thatcauses extensive muscle imbalance about the foot andankle.


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Ankle-Foot Orthosis

y The primary requirement for orthotic support is that

all joints must be passively capable of being positionedin adequate alignment. An orthosis cannot correct afixed bony deformity or fixed joint contracture.

investigations in orthopedics

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