Triple osteotomy of the innominate bone for the treatment of congenital hip dysplasia.

Triple osteotomy of the innominate bone was performed on 12 hips to correct significant, symptomatic hip dysplasia. The procedure used was a modification of Steel's operation, with the modification being removal of a segment of the ischial ramus to facilitate medial displacement and the addition of an acetabular shelf. The patients' ages at surgery ranged from 9 to 22 years, with follow-up of 3-10 years. All patients had clinical improvement in both pain and limp. Radiographically, the average center edge angle improved from 5 to 36.6 degrees. The shelf that was added to buttress further the acetabulum contributed approximately 10 degrees to this improvement in the center edge angle.