Legg–Calvé–Perthes disease

Legg–Calvé–Perthes disease (LCPD) is a childhood hip disorder initiated by a disruption of blood flow to the ball of the femur called the femoral head. Due to the lack of blood flow, the bone dies (osteonecrosis or avascular necrosis) and stops growing. Over time, healing occurs by new blood vessels infiltrating the dead bone and removing the necrotic bone which leads to a loss of bone mass and a weakening of the femoral head. The bone loss leads to some degree of collapse and deformity of the femoral head and sometimes secondary changes to the shape of the hip socket. It is also referred to as idiopathic avascular osteonecrosis of the capital femoral epiphysis of the femoral head since the cause of the interruption of the blood supply of the head of the femur in the hip joint is unknown.

The disease is most commonly found in children between the ages of 4 to 8 but it can occur in children between the ages of 2 to 15. The main long-term problem with this condition is that it can produce a permanent deformity of the femoral head which increases the risk of developing osteoarthritis in adults. It is also commonly known as Perthes disease, or Legg–Perthes disease. Because Perthes' disease is associated with certain clinical features more common in boys such as hyperactivity, small stature for age, delayed bone age, and some minor congenital anomalies, some call this Legg–Calvé–Perthes Syndrome to emphasize that the disease process may not be isolated to the hip joint only.