Legg Calve Perthes disease is a developmental disease of the hip. It starts in late childhood and finishes its course by late childhood. It leads to a deformity of the femoral head. In later life this deformity may give rise to secondary osteo-arthritis of the hip.
The blood supply to the growth plate in the femoral head is compromised and deficient. Hence the bone undergoes necrosis and breaks down. This is a gradual process occuring over several weeks. As blood supply returns, the bone regenerates and reforms. This may take upto three years.
It may result in a deformity of the femoral head. The rounded femoral head becomes flattened and mushroomed. Recent evidence indicates that it may be due to a defect in the clotting mechanism with a tendency to clot formation in the arterioles of the femoral head.