Legg-Calvé-Perthes disease (LPD) is a rare disease that most often affects boys between the ages of 2 and 12. Girls can have LPD. The hips are the main problem. Sometimes both hips are involved, but usually only one side is affected.

With LPD blood flow to the ball of the hip is stopped and bone death occurs. As bone death spreads, the ball develops a fracture of the supporting bone. This fracture signals the beginning of bone reabsorption by the body. As bone is slowly absorbed, the body tries to replace it with new tissue and bone.

Degenerative osteoarthritis can occur with age in adults with LPD. It seems to depend on two things. If the ball reshapes itself and fits into the socket, arthritis is usually not a concern. If the ball does not reshape well, but the socket's shape still conforms to the ball, mild arthritis occurs in later adulthood.

Degenerative arthritis occurs in patients whose femoral head does not shape well and does not fit well in the socket. These patients may need a joint replacement before the age of 50.

Today early treatment can help minimize the effects of LPD. The hope is for a brighter future for today's children who have LPD as treatment continues to improve.