Legg-Calvé-Perthes disease is a rare disease of the hip that afflicts approximately 1 in 1200 children. Of those children, only about one in four are girls. About 5% of all diagnosed develop the disease in both hips (bilaterally). Most of these children are very active and often very athletic. The age of diagnosis is usually between 2 and 12 years old, with the average age of 6. Legg-Calve’-Perthes children tend to be of shorter stature due to delayed bone age.
Legg-Calvé-Perthes disease (LCPD) is a form of osteonecrosis of the hip that is found only in children. It is known by a few other names such as ischemic necrosis of the hip, coxa plana, osteochondritis and avascular necrosis of the femoral head. Most commonly it is called Legg-Perthes disease, LCPD, or Perthes.
LCPD is of unknown origin. It is known that bone death occurs in the ball of the hip due to an interruption in blood flow. As bone death occurs, the ball develops a fracture of the supporting bone. This fracture signals the beginning of bone reabsorption by the body. As bone is slowly absorbed, it is replaced by new tissue and bone.
Reabsorption Phase Reossification Phase/Healed
Four Stages of LCPD
- Femoral head becomes more dense with possible fracture of supporting bone;
- Fragmentation and reabsorption of bone;
- Reossification when new bone has regrown; and
- Healing, when new bone reshapes.
Phase I takes about 6-2 months, Phase 2 takes one year or more, and Phase 3 and 4 may go on for many years.
The first symptoms characterized in LCPD are usually a limp and perhaps pain in the hip, groin, or knee (known as a referred pain). Often you will first notice limping during your child’s active play. They usually cannot tell you an instance when they hurt themselves. They may not be able to tell you exactly where they hurt, especially if the pain is referred toward the knee area. They may not even experience much pain. Other cases may not be diagnosed until some precipitating event (fall, twisting injury) leads to an x-ray that uncovers the previously undiagnosed Legg-Calve’-Perthes disease.
Non-surgical treatments come in varying forms. Crutches are used for non-weight bearing treatment for pain. Casts, traction, and braces help return range of motion and mobility. Range of motion exercises may be given to you by your physical therapist to do with your child in the home.
A “Tenotomy” is a surgery that is performed to release an atrophied muscle that has shortened due to limping. Once released, a cast is applied allowing the muscle to regrow to a more natural length. Cast time is about six to eight weeks.
There are different types of “osteotomies” (cutting the bone to reposition it) and, depending on the need they are performed at different stages of the disease. At times with the softening of the ball, there is the possibility of the ball slipping out of the socket. To protect it, a femoral varus osteotomy, with or without rotation partially redirects the ball into the socket. Another approach to surgically treating Legg-Calve’- Perthes is to do an osteotomy above the hip socket. This allows the surgeon to reposition the hip socket in such a way that the femoral head will have less tendency to become deformed. The shelf arthroplasty gives added coverage of the ball from the top lip of the socket. Both the innominate and the shelf arthroplasty help in reshaping.
To learn more contact:
The National Osteonecrosis Foundation
Johns Hopkins University
School of Medicine, Suite 201
Good Samaritan Professional Building
5601 Loch Raven Boulevard
Baltimore, MD 21239