- Legg-Calvé-Perthes disease (LCPD) is a hip disorder secondary to idiopathic ischemic osteonecrosis of the femoral head.
- Eventually leads to impaired growth of epiphysis and deformity of femoral head
- Seen in pediatric patient population
- Majority of cases are unilateral. 10% of cases are bilateral and generally do not occur simultaneously.
- System(s) affected: musculoskeletal
- Predominant age: Susceptible age is 2 to 12 years. ~80% occurs between the ages of 4 and 9 years.
- Predominant sex: male > female (4:1)
- In bilateral cases, males predominate (7:1). However, females seem to have more severe involvement.
Annual international incidence of 1:1,200
Etiology and Pathophysiology
- Generally idiopathic but may be due to trauma, sickle cell crisis, congenital dislocation of the hip, toxic synovitis
- Interruption of the blood supply to the femoral epiphysis causing femoral head osteonecrosis
- Deformity may result from growth arrest of the capital femoral epiphysis and physis, asymmetrical repair, iatrogenic causes, or devitalized articular cartilage and weakening mechanical properties of bone leading to trabecular collapse.
No specific gene locus has been identified for LCPD. Avascular necrosis of femoral head (unrelated to LCPD) may develop sporadically or as autosomal dominant disorder with type II collagen mutation.
Increased risk in children with the following:
- Low birth weight (<1,500 g)
- Maternal smoking during pregnancy
- Factors predisposing to thrombophilia (e.g., factor V Leiden deficiency, protein C or S deficiency) (1)
- Congenital genitourinary disorders (hypospadias, undescended testes, inguinal hernia)
- Lower socioeconomic status
- Exposure to secondhand smoke
- Caucasian and Asian ethnicities have the highest frequency.
- Generalized behavioral disorder (but not attention deficit disorder)
No clear prevention measures exist.
Commonly Associated Conditions
- Short stature
- Delayed bone age (observed in 89% of LCPD patients)
- Possible association with hypercoagulable states (see “Risk Factors”)
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