Legg-Calve-Perthes disease is when the ball of the thighbone in the hip doesn't get enough blood, causing the bone to die.

Legg-Calve-Perthes disease usually occurs in boys 4 - 10 years old. There are many theories about the cause of this disease, but little is actually known.

Without enough blood to the area, the bone dies. The ball of the hip will collapse and become flat. Usually only one hip is affected, although it can occur on both sides.

The blood supply returns over several months, bringing in new bone cells. The new cells gradually replace the dead bone over 2 - 3 years.

The first symptom is often limping, usually painless.

Other symptoms may include:

• Knee pain
• Persistent thigh or groin pain
• Wasting of muscles in the upper thigh
• Apparent shortening of the leg, or legs of unequal length
• Hip stiffness that restricts movement in the hip
• Limited range of motion

During a physical examination, the health care provider will look for a loss in hip motion and a typical limp. A hip x-ray or pelvis x-ray may show signs of Legg-Calve-Perthes disease.

The goal of treatment is to keep the ball of the thighbone inside the socket. Your health care provider may call this "containment." Containment is achieved by maintaining a good range of motion of the hip. In some cases, bracing is used to assist with containment.

Physical therapy and anti-inflammatory medicine (such as ibuprofen) can relieve stiffness in the hip joint. When the hip is painful, or the limp gets worse, restricting activities such as running may help reduce the inflammation. Night-time traction may also help.

Health care providers no longer recommend several months of bedrest.

When these steps fail, surgery may be needed. Surgery ranges from simple lengthening of a groin muscle to major hip surgery to reshape the pelvis. The type of surgery depends on the severity of the problem and the shape of the ball of the hip joint.

The outlook depends on the child's age and the severity of the disease. In general, the younger the child is when the disease starts, the better the outcome.

Children younger than 6 who receive treatment are more likely to end up with a normal hip joint. Children older than age 6 are more likely to end up with a deformed hip join, despite treatment, and may later develop arthritis.

Osteoarthritis may develop later in life. Early recognition and proper treatment of Legg-Calve-Perthes disease may minimize this complication.

Call for an appointment with your health care provider if a child develops any symptoms of this disorder.

Hosalkar HS, Horn D, Friedman JE, Dormans JP. The Hip. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap. 677.