This study examined the clinical, functional and radiological results of total hip arthroplasty with subtrochanteric shortening osteotomy in severe dysplasia of hip.

Seventeen cases of severe dysplasia of the hip, which were treated with total hip arthroplasty with subtrochanteric shortening osteotomy from August 1997 to September 2004, were evaluated. The mean follow-up duration was 52.9 months (range: 26~106). Harris hip score (HHS), leg length discrepancy (LLD) and complication were assessed clinically. Gait analysis (7 cases) and Cybex study (8 cases) for the abductor muscle power were assessed functionally. Bony union and stability around the osteotomy site of the femoral and acetabular components was assessed radiologically.

The mean HHS improved from 65.1 (range: 23~87) points preoperatively to 88.2 (range: 72~100) points at the last follow-up. The mean LLD improved from 3.7 (range: 1~7) cm preoperatively to 1.6 (range: 0.5~3.3) cm postoperatively. All cases showed complete bony union of the allograft in the acetabulum and osteotomy site at a mean time of 6 months postoperatively. Gait analysis improved in all cases but there was some limping gait remaining. On the Cybex study, 6 out of 8 cases showed improved abductor muscle peak toque, postoperatively.

A cementless total hip arthroplasty with subtrochanteric shortening osteotomy is believed to be a useful treatment for severe dysplasia of hip. Despite the improving HHS, the abductor power can be decreased. In these points, gait analysis and the Cybex study are helpful on the follow-up.