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What Is Legg-Calvé-Perthes Disease?

Legg-Calvé-Perthes disease (also known as Perthes) is a condition in which the blood supply to the hip bone is temporarily interrupted, causing the bone in the hip to deteriorate. The hip is a ball-and-socket joint, and Perthes primarily affects the “ball” portion of the joint, also known as the femoral head.

Gradually, the weakened bone is removed by the child’s body and is replaced by new bone growth. During this process of bone removal and replacement, the femoral head becomes fragile and can become misshapen, potentially leading to future hip problems. The most active portion of the bone absorption and bone healing typically occurs over a period of two years, but complete healing can take up to three to five years.

Perthes disease affects the hip; it does not develop in other joints.

What Causes Perthes Disease?

The cause of Perthes is unknown. The condition usually occurs in children from 4 to 8 years of age, but can occur between ages 18 months to 14 years.

The disease often develops in children who are very physically active. In most children, the condition typically occurs in one of their hips, and only approximately 10 – 15% of children have both of their hips affected.

Perthes is rare, with an incidence of roughly 3 to 6 per 100,000 children in North America. The condition affects boys four to five times more than girls.