Our six year old child is now undergoing treatment for Perthes bone disease. The doctor can’t be sure but thinks it was caught early enough. We’ve been told that he’ll come out okay. What does that mean? Will the treatment hold up? What will happen to his hip 30 years from now?

Perthes disease is also known as Legg-Calvé-Perthes disease. It is an idiopathic avascular necrosis of the proximal femoral epiphysis. Idiopathic means we don’t know yet what causes it. Certain ethnic groups seem to be at higher risk. There may be a link between delay in bone growth and this condition.

Avascular refers to a loss of blood supply to the head of the femur (thigh bone). This leads to necrosis or death of bone tissue. The epiphysis or growth plate is directly affected.

The disease can range from mild to severe. The round shape of the femoral head becomes flattened and misshapen. Pain and loss of motion can affect how the child walks and runs. In severe cases, the femoral head can collapse.

Osteoarthritis can develop early in the adult years for those children who had moderate to severe Perthes disease. Treatment is aimed at preventing all of these complications.

Younger children have the best chance of good results by avoiding deformity. Older children (more than 10 years old) seem to be at greatest risk for a poor outcome.

Hip arthritis seems to be a natural result in adults who had Legg-Calvé-Perthes disease as a child. The more severe the condition and the later it was diagnosed, the more likely the individual will develop arthritis. Many adults have a hip replacement by the time they are in their mid-50s.