[A comparative study of the role of two femoral shortening techniques in total hip arthroplasty on patients with Crowe's IV congenital dislocated hips]

To compare proximal femoral resection with transverse subtrochanteric osteotomy in the treatment of Crowe's IV congenital dislocated hip (CDH) with total hip arthroplasty (THA).Thirty-six primary hip arthroplasties were performed in patients with Crowe grade IV CDH from April 2003 to October 2007. These patients were divided into two groups, one for proximal femoral resection (n = 20) and another for subtrochanteric osteotomy (n = 16). The leg length discrepancy, rotation center height and Harris score were measured pre- and post-operation to compare the two methods of osteotomy.All surgeries were successfully performed. The average leg discrepancy was 0.6 cm (range from 0 to 1.5 cm) for subtrochanteric osteotomy group and 0.3 cm (range from -1.0 to 1.5 cm) for proximal femoral resection group, there was no significant difference between them (P0.05). There were also no statistically significant difference between the two groups in other index. The complication rates were much higher in the proximal femoral resection group. At the latest follow up, the Harris score of subtrochanteric osteotomy group was 90 +/- 6, and the proximal femoral resection group was 83 +/- 8. There was statistical difference between the two groups (P0.05).Although both the femoral shortening techniques can restore the leg length of Crowe IV CDH, the subtrochanteric osteotomy technique has advantage of avoiding the potential complications in the high riding patients (high dislocation4 cm).