Definition Perthes disease is inflammation of the femoral head, possibly due to loss of blood supply. The femoral head is the ball on the end of the thighbone that fits into the socket of the hip joint. This disease may eventually lead to destruction of the femoral head.
What is going on in the body? If the blood supply to the femoral head is lost for any reason, the bone cells die. This can potentially cause the round femoral head to lose its shape, followed by arthritis. This disease typically occurs between the ages of 4 and 8 years. Boys are 4 times more likely to be affected than girls. Ninety percent of the time, only one hip is affected.
What are the signs and symptoms of the disease? The main symptoms are pain in the thigh and groin areas and limping. Sometimes the pattern of pain is not the typical ache in the groin. The pain may extend down the front of the thigh to the knee, seeming to be a knee problem. Movement of the hip may be restricted and painful, especially when spreading the legs apart.
What are the causes and risks of the disease? The exact cause is unknown, but thought to be linked to disrupted blood supply to the bone.
What can be done to prevent the disease? There is no prevention for this disease.
How is the disease diagnosed? This disease must be considered in any child with hip or knee pain. Symptoms and signs are helpful in making the diagnosis. Several weeks after onset, X-rays can show minor changes in the femoral head. Much later, the head may collapse and flatten; arthritis may develop. If X-rays are initially normal and suspicion is high, additional testing with a bone scan or a special X-ray test known as MRI (magnetic resonance imaging) can confirm the diagnosis.
What are the long-term effects of the disease? About 50% of children, even with no treatment, will do well. The other half of affected children may have some arthritis problems, even as teenagers. The older the child at the time of onset, the worse the prognosis or anticipated results. Prognosis is especially poor if the head cannot fit securely in the pelvis and partially dislocates.
What are the risks to others? There are no risks to others.
What are the treatments for the disease? The goal of treatment is to prevent arthritis. This is done by protecting the femoral head during the healing process, which takes many months. During this time, the femoral head must be secure within the socket of the hip joint. Some controversy surrounds treatment recommendations.
Initially, rest and restricted weight bearing can improve the comfort in the hip. This minimal treatment or none at all may be sufficient for a child under the age of 5 or 6 years without partial dislocation of the hip. Similar observation may be appropriate for an older child when there is no involvement of the weight-bearing part of the femoral head. Before any other treatment is started, motion of the hip must be regained through gentle range-of-motion exercises.
When the hip is more involved in an older child, bracing of the joint may be recommended. Finally, an operation may be needed to redirect the position of the socket or change the angle of the femoral head to fit into the socket. In rare cases when severe arthritis develops, a hip fusion operation, which involves joining the bone of the joint together solidly, may be required. A total hip replacement may become necessary in an older adult.
What are the side effects of the treatments? Hip arthritis, stiffness, and pain may follow treatment. With any operation, infection and bleeding are possible. In addition, the bones may not heal. Flattening of the head, causing it to lose its round shape, or partial dislocation may lead to a poor outcome.
What happens after treatment for the disease? If full recovery occurs, a person can generally go back to normal activities. If symptoms continue, further treatment may be required.
How is the disease monitored? After treatment, the presence of pain, stiffness and any limp should be monitored.
Author: John A.K. Davies, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
