Children aged 8 or older have a poorer prognosis with Perthes disease. Although definate evidence is lacking it is thought that certain children with more severe disease may benefit from surgery to improve coverage of the femoral head by the socket. This is usually only indicated before reossification of the femoral head occurs.
Coverage can be achieved by dividing the pelvis and repositioning it (Salter osteotomy, Triple pelvic osteotomy). More frequently, the femur is divided (femoral varus osteotomy) and repositioned under the socket. This operation requires a hospital stay of about 3 days. The osteotomy is held with a metal plate which is removed after one year. Patients are not allowed to weight bear for approximately 6 weeks while the bone heals. Sometimes the legs are placed in a cast (broomstick cast) for about 3 weeks post operatively to make sure that the hip does not loose range of abduction movement. The affected leg is often made 1-1.5cm shorter by this operation but will usually catch up with the opposite leg within 12-18 months.