Valgus osteotomy for hinge abduction.

Failure of the enlarged and deformed anterolateral portion of the femoral head to roll into the acetabulum during abduction alters hip joint mechanics. The resultant hinge abduction is associated with pain, and the patient often has restricted movement. A valgus osteotomy removes the deformed portion of the femoral head away from the weight-bearing area and ensures there is pain-free congruent range of movement around the weight-bearing position. The concomitant improvement in lever arm function and leg length results in a better gait pattern. In immature patients, abolition of hinge abduction allows the lateral acetabular ossification center to grow more normally.