Clinical Presentation

A 6-year-old male presents with a painless limp.

Figure 91A

Figure 91B

Radiologic Findings

Legg-Calvé-Perthes disease (LCP)

Differential Diagnosis/Consideration

• Meyer’s dysplasia
  
• Multiple epiphyseal dysplasia
  
• Spondyloepiphyseal dysplasia
  
• Hypothyroidism
  
• Avascular necrosis secondary to:
  
  
  
  • Sickle-cell disease
    
  • Gaucher’s disease
    
  • Trauma
    
  • Steroid use

Discussion

Background

LCP is an osteochondrosis affecting the femoral head. The process is generally seen in Caucasian children 3 to 12 years of age, with a peak incidence between 4 and 8 years. Males are afflicted 5 times more frequently than females, with both hips involved in 10 to 15% of patients. Decreased birth weight, low socioeconomic class, attention-deficit disorder, delayed bone maturation, exposure to passive smoke, and abnormal birth presentation are all associated with an increased risk of LCP. A family history is seen in ~6% of cases.

Etiology

The origin remains uncertain; however, clotting abnormalities with resulting episodes of vascular thrombosis may play a role. Toxic synovitis, noted as a precursor for LCP in 1 to 3% of cases, however, is probably not a cause.

Clinical Findings

Children classically present with a painless limp, although in the “synovitis phase” pain can be present, which may be referred to the knee. The pain is typically worse with activity and lessened with rest. Limitation of abduction and internal rotation of the hip, with resistance of “to and fro” rolling motion (+ log roll test) is found on physical examination. Atrophy of buttock, calf, and thigh musculature can be seen with long-standing disease. Leg-length discrepancy may be noted in more severe cases.

Complications

Premature hip osteoarthritis may develop in the fourth or fifth decade, often necessitating hip arthroplasty. Osteochondritis dessicans develops in <5% of patients, often after a long symptom-free interval. Lateral extrusion of epiphysis can lead to “hinge” abduction, the result of failure of the femoral head to rotate medial with hip abduction due to blocking of the flattened femoral head on the lateral acetabular margin.

Figure 91C AP radiograph of pelvis demonstrates a slightly flattened, sclerotic left femoral head epiphyseal center (arrows), which shows apparent mild lateral subluxation.

Figure 91D Coned AP view of left hip depicts a subchondral fissure (arrowheads) spanning >50% of a slightly small, flattened sclerotic epiphyseal center.

Pathology

Four stages are typically described with all the osteochondroses:

• Initial stage: osteocytic death
  
• Second stage: revascularization of the bone with fissuring of necrotic segments; articular cartilage continues to grow because nutrient supply is from the synovial fluid
  
• Third stage: resorption of necrotic bone and new bone formation
  
• Final stage: development of mature haversian systems

Imaging Findings

RADIOGRAPHY