Legg-Calve-Perthes syndrome, also known as Perthes disease, is a rare childhood condition that affects the hip joint. It occurs when the blood supply to the femoral head (the ball-shaped part of the hip joint) is temporarily disrupted, leading to bone cell death and eventual bone collapse. Over time, the body heals and regenerates the affected bone, but the process can result in an irregularly shaped femoral head, causing pain and limited mobility.