Legg-Calvé-Perthes disease is a rare disorder in children in which the rounded femoral head stops receiving blood supply. As a result, the femoral head collapses. The body will absorb the dead bone cells and replace them with new bone cells. Eventually, the new bone cells will return the head of the femur to shape. Legg-Calvé-Perthes disease causes pain and stiffness in the hip joint for a time. It is important to mention that this disease usually occurs in children between 2 and 12 years of age and in most cases, only one of the hips is affected.