Case of the Week: August 21-August 28, 2002

5 year old with Hip Pain, Limp and Limited Motion.

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Case Details

Plain Film: There is flattening and sclerosis and irregular mineralization of the right femoral head. NM Bone Scan: Decreased tracer uptake is evident in the region of the right femoral head

Answer

Diagnosis: Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is also known as idiopathic avascular necrosis of the hip. It is a condition resulting from idiopathic infarction of the bony epiphysis of the femoral head. The most frequent age range of presentation is 5-8 years (when the femoral head is most susceptible to interruption of vascular supply). The condition is often associated with skeletal immaturity. There is a male predominance, with a male:female ratio of 5:1. The disease is usually asymmetric, but can be bilateral in 13%--usually sequential, rather than recurrent. The usual symptoms are limp, with groin, thigh or knee pain.

IMAGING FINDINGS:

Plain radiographs (PF) are typically positive at the time of presentation, even early.

Early findings: 

  • Widened joint space

    • With joint effusion or synovial hypertrophy

  • Subchondral linear lucency

    • Crescent sign

    • Best seen on frog-leg views

    • Represents fracture through necrotic bone

Late findings:

  • Fragmentation of femoral epiphysis

  • Increased sclerosis/lucency of femoral epiphysis

  • Loss of height (collapse) of femoral epiphysis

Chronic findings:

  • Broad, overgrown femoral head (coxa magna)

  • Short femoral neck

  • Physeal arrest

NM Scintigraphy:

  • Early: Decreased tracer uptake due to interruption of blood supply

  • Late Increased tracer uptake due to revascularization/repair

MR Imaging:

  • Image both hips - look for asymmetric appearance of femoral epiphysis

  • Hypointense epiphyseal marrow center on T1-weighted images

  • Marrow edema on T2-weighted images

DIFFERENTIAL DIAGNOSIS:

  • Septic arthritis

  • Toxic synovitis

  • Osteomyelitis

  • Langerhans cell histiocytosis

  • Slipped capital femoral epiphysis

  • Juvenile rheumatoid arthritis

TREATMENT:

Treatment and significance of radiographic findings is controversial. Approximately 50% will improve with no treatment. Others may require bracing or a femoral osteotomy. Acetabular reconstruction may be required to provide coverage of the femoral head. 

PROGNOSIS:

Younger age at presentation yields A better prognosis. Findings associated with poor prognosis include: Female gender, calcification/lytic area lateral to the epiphysis, metaphyseal lucency, increased epiphyseal extrusion at greater than 20%, and greater than 50% femoral head involvement. 86% of children will develop osteoarthritis.

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VCU Department of Pediatric Radiology Virginia Commonwealth University VCU Medical Center