Patients who had not had prior muscle release surgery or whose contracture had reoccurred and limited hip abduction, first had an open complete release of the adductor longus and brevis, gracilus, and an anterior branch obturator neurectomy. This was followed with a varus osteotmy using the AO blade plate as previously described. The chisel was inserted with the goal of creating 90 to 100 degrees varus neck-shaft angle for non- ambulators and 110 to 120 degree neck-shaft angle for

ambulators. After the femoral osteotomy, care was taken to remove the whole lesser trocanter including the cartilage cap to provide a complete release of the iliopsoas for marginal or non- ambulators. For community ambulators, intermusclar lengthening of the Iliopsoas is performed with preservation of the lesser trocanter on the proximal fragment. Next, the proximal fragment is abducted and evaluated under fluoroscopy to document that the femoral head will reduce into the acetabulum . If it does not reduce, an anterior and medial capsulectomy is performed through the femoral osteotomy. By abducting the proximal fragment good visualization of the medial capsule is possible and the aspect of the capsule which prevents reduction can easily be released. If the femoral head does reduce with abduction but continues to be unstable in the acetabular with superior pressure or had windshield wiper movement with 30 degrees of abduction in the expected range after fixation of the osteotomy or the sourcil of the acetabulum slopes superiorly or is diffuse, a pelvic osteotomy was indicated. This was done before fixation of the femoral osteotomy by packing the femoral site leaving the proximal fragment abducted. An anterior bikini incision was made just distal to the anterior supior iliaec spine. The iliac apophysis was split and the lateral aspect of the ileum only was subperiosteally exposed down to the hip capsule. The interval between sartorius and fascia lata was developed down to the anterior inferior spine. The interval between the iliac spines was incised and the capsule

was identified from the inferior iliac spine all the way posterior to the triradiate cartilage. The posterior dissection was performed using a cobb elevator, however the sciatic notch is not entered. The posterior dissection is all inferior to the sciatic notch. Using a 4- 6 mm wide straight osteotome with constant fluoroscopic control the initial cut is made directly lateral to medial starting 3- 5 mm above the osseous corner

of the acetabulum directed medially to the middle of the triradiate cartilage. The cut is than completed anteriorly with the anterior 1 cm cutting across both tables of the ileum. The cut is continued posteriorly by continuing to aim at the center of the triradiate cartilage making sure that all of the posterior cortex is cut down to the triradiate. With the osteotome in the most posterior aspect of the osteotomy, the osteotomy should easily open. A tricortical bank bone graft is cut into a triangle 10 - 15 mm tall and long enough to be just short of the triradiate cartilage. The posterior graft is inserted first trying to get it directed anteriorly so there is more opening posterior. A second smaller anterior graft is next inserted. The position of the hip is now checked under fluoroscopy to make sure that it remains stable with movement in the expected range after fixation of the femoral osteotomy. After this the femoral osteotomy is reduced and held manually with the hip flexed 90 degrees and the knee fully extended. The femur is shortened so the osteotomy has no compression force in the straight leg raising position. This usually requires 2- 6 cm of further femoral shortening. If the patient is a very function ambulator than distal hamstring lengthening should be done first so less femoral shortening is required. The femoral osteotomy is next fixed with an AO blade plate. Careful attention is given to placing the femur in zero to 15 degrees anteversion so the knee should rest in external rotation with the hip extended and the hip must come to neutral rotation at 90 degrees of knee and hip flexion for comfort and ease of sitting. Retroversion must be avoided. If the contra- lateral hip is also subluxated or dislocated the same procedure is performed at the same setting. If the opposite leg had an abduction contracture or was more than 2 cm longer, a concurrent varus osteotomy was performed to provide for symmetrical hip motion and leg length.

An xray at the conclusion of the procedure should show well reduced hips which are symmetrical and well covered. The windswept position pre-operatively if present must be converted to as symmetrical a position post-operatively as possible.

The outcome of this procedure is reliable and good on follow-up.

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