Premature femoral neck physeal closure in Perthes' disease.

One hundred premature femoral neck physeal closures in 430 hips with Perthes' disease have occurred in two patterns central and lateral. Abnormal physeal growth can be demonstrated early by a narrowed physeal plate with overlying avascular epiphysis and marked metaphyseal reaction below. Subsequently, a bony bridge forms between the metaphysis and epiphysis. If the physeal closure is central, the mature hip will have a short femoral neck, a relatively round femoral head, a trochanter that has overgrown the femoral head, a short leg, and a mildly deformed acetabulum. If the physeal closure is lateral, the mature hip will have a femoral head that is externally tilted as the medial neck lengthens and the lateral neck remains short, a trochanter that has overgrown the femoral head, an oval femoral head, a short leg, and a deformed acetabulum. A physeal arrest is a contraindication for a varus osteotomy because it accentuates the deformity, especially in the greater trochanter. The leg-length discrepancy may be treated by epiphysiodesis of the contralateral femur, when necessary, and the abductor muscle insufficiency may be treated by an exercise program or distal and lateral transfer of the greater trochanter.