Signs and symptoms of Legg-Calve-Perthes disease include:

• Limping
• Pain or stiffness in the hip, groin, thigh or knee
• Limited range of motion of the hip joint

Legg-Calve-Perthes disease usually involves just one hip. Both hips are affected in some children, usually at different times.

Legg-Calve-Perthes disease occurs when too little blood is supplied to the ball portion of the hip joint (femoral head). Without an adequate blood supply, this bone becomes unstable, and it may break easily and heal poorly. The underlying cause of the temporary reduction in blood flow to the femoral head is still unknown.

Risk factors for Legg-Calve-Perthes disease include:

• Age. Although Legg-Calve-Perthes disease can affect children of nearly any age, it most commonly begins between ages 4 and 8.
• Your child's sex. Legg-Calve-Perthes is up to five times more common in boys than in girls.
• Race. White children are more likely to develop the disorder than are black children.
• Genetic mutations. In a small number of cases, Legg-Calve-Perthes disease appears to be linked to mutations in certain genes.

Children who have had Legg-Calve-Perthes disease are at higher risk of developing hip arthritis in adulthood — particularly if the hip joint heals in an abnormal shape. If the hip bones don't fit together well after healing, the joint can wear out early.

In general, children who are diagnosed with Legg-Calve-Perthes after age 6 are more likely to develop hip problems later in life. The younger the child is at the time of diagnosis, the better the chances for the hip joint to heal in a normal, round shape.