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 re-forms 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 an abnormal shape and does not fit properly into the
hip socket, causing stiffness and pain. The cause of LCPD is unknown.