This is a rare condition which results from loss of blood supply to the femoral head. The femoral head is the upper end of the femur (thigh bone) and is normally round. The cause of the interruption in blood supply is not known but may, in some patients, occur after a common viral infection. When the femoral head does not receive enough blood, it becomes susceptible to collapse or small fractures, which deforms its round shape.

At what age does Legg-Perthes Disease occur?
Generally, the peak incidence is 5-7 years of age, but children from age 2-12 may be affected. In 10% of cases, the condition occurs on both sides (bilaterally). Some of these cases do not develop problems on the other side for several months or years later.

Who is more likely to get Legg-Perthes Disease?

• Males (twice as often as females)
• Short stature
• Delayed growth
• Breech delivery
• Caucasians
• Family history (Legg-Perthes in a first-degree relative)

What are the symptoms of Legg-Perthes Disease?
Initially your child may limp occasionally with no complaints of pain. 50% of children do not have pain at the onset of the condition. Pain may occur at the hip or knee. In some patients, the entire femoral head (ball) is affected, while in others, only a small portion is affected. Symptoms vary with the severity of the abnormality, though all patients initially have loss of hip motion due to inflammation.

What is the treatment for Legg-Perthes Disease?
There is controversy regarding the treatment. The area of bone which has lost its blood supply will heal. New blood supply will come into this area over a period of 14-18 months. All agree that the primary focus of treatment is to restore motion of the hip. This can be very difficult in some cases and relatively easy in others. Restriction of activities is necessary to reduce the inflammation. For some patients, it may mean stopping soccer and PE, while for others, it may mean being in wheelchair for a period of time. For very severe cases and in situations where a child’s activities cannot be controlled, long leg casts with a bar attaching the two cast together may be advised. Bed-rest and traction was used successfully in the past and remains an option, but for most family situations it is not an option today. In follow-up visits with your doctor, the motion of the hip will be checked and will be the primary concern. Anti-inflammatory medications may be used to decrease the inflammation and pain in the hip. This type of medication does not speed the healing process and may have side effects. Your doctor may recommend its use for short periods of time. There is less agreement on the role of various surgical procedures. For selected patients, surgery may be appropriate and may be advised by your doctor.

More Information:
Pediatric Orthopaedic Society: http://www.posna.org/InfoParents/Perthes.htm
Medline Information: http://www.nlm.nih.gov/medlineplus/osteonecrosis.html
Medline Encyclopedia: http://www.nlm.nih.gov/medlineplus/ency/article/001264.htm