Osteochondritis dissecans

Osteochondritis dissecans

OVERVIEW:

Condition in which segment of articular and underlying subchondral bone becomes separated from surrounding bone.

System(s) affected: Musculoskeletal
Genetics: No distinct genetic pattern known
Incidence/Prevalence in USA: Unknown
Predominant age: 2 main age groups; children under 12 years old and young adults
Predominant sex: Male > Female (3:1)

SIGNS AND SYMPTOMS:

• Intermittent joint pain, clicking, swelling, locking and stiffness
• May be asymptomatic until the fragment detaches, then experience locking of the joint or giving way in the knee
• Focal tenderness over involved part of joint
• May have effusion, atrophy of supporting musculature, crepitus, decreased range of motion

CAUSES:

Most widely accepted theories are:
• Trauma (direct or indirect)
versus
• Ischemic theory due to focal insufficiency in end-arterial blood supply leading to necrosis
• Accessory growth centers that may have arterial supply disrupted leading to typical osteochondritis dissecans lesion (unlikely)

RISK FACTORS:

No apparent genetic predisposition

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS:

• Meniscal tear
• Osteochondral fractures
• Patellalgia
• Anomalous ossification center especially in lat condyle

LABORATORY:

No specific tests

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS:

• Primary change in the bone
• Avascular necrosis occurs in a focal area
• Overlying cartilage changes are secondary to the bony changes
• Loss of subchondral bone support leads to degenerative. cartilage changes - softening, fibromatous, fissuring
• Fragment may detach and become loose body with traumatic event
• Healing occurs by revascularization and creeping substitution

SPECIAL TESTS:

N/A

IMAGING:

• Plain radiographs - AP, lateral and tunnel view, first study to confirm diagnosis. Appears as a well demarcated fragment of bone surrounded by a radiolucent zone. If separated, the fragment may be seen elsewhere in the joint and a defect is present in the articular surface.
• Technetium 99 bone scan - now of historic value; was used to evaluate healing potential.
• CT scan - provides architectural description of lesion. Essentially replaced by MRI.
• MRI
• Very useful to delineate bony lesion
• Difficult to assess and identify the status of overlying articular cartilage. Healing progression difficult to follow.

DIAGNOSTIC PROCEDURES:

• Arthroscopy - definitive procedure to assess the underlying cartilage and for definitive treatment

TREATMENT

APPROPRIATE HEALTH CARE:

Outpatient usually; inpatient for surgery

GENERAL MEASURES:

• Goals of treatment - maintain smooth congruous joint surface. Alleviate pain. Prevent degenerative joint disease. Promote revascularization of necrotic fragment.
• Splinting, crutches, non-weight bearing with active range of motion is the norm

SURGICAL MEASURES:

On occasion, early surgical intervention is needed. Orthopedic consultation recommended.

ACTIVITY:

• Non-weight bearing, immobilization with intermittent maintenance of range of motion
• Follow closely for 12 weeks for healing; fragment displacement may occur, in which case arthroscopy is indicated.

DIET:

No specific diet recommended

PATIENT EDUCATION:

• Compliance with immobilization and possibility of further trauma should be emphasized.
• Most lesions heal without surgical intervention.

MEDICATIONS

DRUG(S) OF CHOICE:

• NSAIDs (e.g., ibuprofen 20-30 mg/kg/day)

Contraindications: N/A
Precautions: N/A
Significant possible interactions: N/A

ALTERNATIVE DRUGS:

N/A

FOLLOW UP

PATIENT MONITORING:

Initially should be followed every 6-8 weeks with serial radiographs to check for healing and possible displacement. Expect healing in 3 months. In one year radiographs usually show no residual abnormality.

PREVENTION/AVOIDANCE:

No clear way to avoid its development.

POSSIBLE COMPLICATIONS:

• Failure to revascularize and heal
• Displacement of fragment becoming loose body within a joint

EXPECTED COURSE AND PROGNOSIS:

• Most will heal without morbidity
• An incongruous joint surface may lead to degenerative changes if not managed adequately

MISCELLANEOUS

ASSOCIATED CONDITIONS:

N/A

AGE-RELATED FACTORS:

Pediatric: N/A
Geriatric: N/A
Others: N/A

PREGNANCY:

N/A

SYNONYMS:

N/A

ICD-9-CM:

732.7 Osteochondritis dissecans

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Medical Diagnosis » O » Osteochondritis dissecans