Cementless total hip arthroplasty for patients previously treated with femoral osteotomy for hip dysplasia: the incidence of periprosthetic fracture.

Abstract

Femur deformities can make stem fixation difficult in total hip arthroplasty (THA). We report the clinical results of cementless THA using a press-fit stem in patients who had previously undergone femoral osteotomy for hip dysplasia. The subjects included 66 hips in 64 patients, with the mean follow-up period of 7.3years. THA was performed at a mean period of 17.1years after intertrochanteric femoral osteotomy. Valgus osteotomy was performed in 42 hips, and varus osteotomy in 24. Clinical results were evaluated by using the Merle d'Aubigne-Postel score. Implant survival was determined with revision as the end point, and any related complications were investigated. The Merle d'Aubigne-Postel score improved from 9.4 to 16.1 at the final follow-up, without any implant loosening. However, periprosthetic femoral fractures were observed in four hips (6.0%), one intra-operatively and three within three weeks after THA. Among these cases, three hips previously had varus osteotomy (12.5%) and one hip had valgus osteotomy (2.3%). Two hips were revised with full porous stems and circumferential wiring. The five and ten year cumulative survivorship rates were 97% (range, 88.8-99.3%) and 97% (88.8-99.3%), respectively. Although the use of a press-fit cementless stem yielded acceptable results in most of the patients, perioperative femoral fracture was a major complication especially in the patients previously treated with intertrochanteric varus osteotomy. Careful planning and implant selection could be emphasized for these cases.