Definition:

Avascular necrosis of the femoral head (ANFH) is one of the most common diseases of osteonecrosis that leads to destruction of the hip joint. Osteonecrosis is a pathological process in which cellular death in the bone constituents occurs because of decreased blood flow or an interruption in the blood supply. ANFH occurs mainly in young individuals between 30 and 50 years old. The clinical manifestations of ANFH, including pain on exertion, limping gait, and discrepancy in leg length, cause considerable disability. The etiology of ANFH is unknown, but previous studies have indicated that heritable thrombophilia and hypofibrinolysis, alcohol intake, and steroid use are risk factors for ANFH. It has been reported that Legg-Calve-Perthes disease [DS:H01526] is a particular type of femoral head necrosis occurring in children. Most cases are sporadic, but familial cases have been described. It has been reported that COL2A1 mutations are associated with this disease. Recent studies have suggested that an association exists between ANFH and genetic polymorphisms in the plasminogen activator inhibitor (SERPINE1), vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (NOS3), and P-glycoprotein (ABCB1) genes.