Legg-Calvé-Perthes disease (LCP) is a rare childhood condition characterized by osteonecrosis of the hip (the capital femoral epiphysis) due to an interruption in blood flow (ischemia). Ischemia is reversible in LCP because the necrotic area shows revascularization which allows the regeneration of capital femoral epiphysis. Disease severity varies widely and necrosis is most often unilateral (95% of the cases). Signs and symptoms of LCP usually include limp and pain in the hip, pain in the groin and knee, and inability to move the affected leg normally. Disease onset usually occurs between the ages of four and ten years. Males are four times more affected than females; however, the severity is more in females. Most LCP cases are found to be in Asians, Eskimos, and Whites. The general prevalence is estimated to be 1:1200 children. Children with perinatal HIV infection or those who have a tendency to thrombosis (for example, protein C deficiency) are found to be more predisposed to LCP than others. Other risk factors may include short stature with hyperactivity and exposure to secondhand smoke.
Diagnosis of LCP primarily depends on bone images via X-ray, MRI, bone scan, or scintigraphy (two-dimensional picture of a body radiation source is obtained through the use of radioisotopes). The most important steps in treatment are non-weight bearing with crutch walking for several months and containment of the femoral head with the acetabulum, if necessary.
The exact cause of LCP is unknown, but families with several affected members have been reported. Studies have indicated LCP to follow autosomal dominant inheritance as well as multifactorial inheritance. More recently, a missense mutation in the COL2A1 gene was detected in a Japanese family with LCP.