Adolescent hip pain after Perthes' disease.

Whereas the majority of patients with Perthes' disease have relatively benign diseases with good long-term outcome, approximately 9.5% develop deteriorating symptoms that require surgery before the age of 35 years. The growth disturbance that produces the deformity of the femoral head induces a fixed subluxation, resulting in hinge abduction. This condition almost certainly leads to the early onset of degenerative changes. Abduction extension osteotomy relieves pain, improving leg length discrepancies and range of movement. The surgeon hopes that the operation will sustain long-term hip function.