Legg-Calve-Perthes disease (LCPD) is a disorder that affects the upper part of the thighbone (head of the femur). It occurs most frequently in children between the ages of 3 and 12. Boys are affected about 4 to 5 times as often as girls. Usually only one hip is affected, although it is possible to have LCPD in both hips.

LCPD develops because of loss of blood flow to the head of the femur. This causes breakdown (avascular necrosis) and deformity of the femur in this area. The bone reforms in the hip area when the blood supply returns to normal. During this time, the femur is soft and may easily fracture and collapse. The head of the femur heals in a abnormal shape and does not fit properly into the hip socket, causing stiffness and pain. The cause of LCPD is unknown.

Symptoms of LCPD include:

• Difficulty walking or walking with a limp.
• Pain in the hip, knee, thigh, or groin.
• Muscle spasms.
• Loss of muscle mass (atrophy) in the upper thigh.
• Decreased movement and stiffness of the hip.
• Shortened height.

Treatment depends on the severity of symptoms but may include physical therapy, a brace or cast, or surgery. Occasionally the disease heals on its own without treatment.