Cementless total hip arthroplasty using custom stem and reinforcement ring in hip osteoarthritis following developmental dysplasia.

The anatomical deformities encountered in osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) may lead to some technical difficulties when performing total hip arthroplasty. The aim of this study is to present our experience in anatomical analysis of OA following DDH and its treatment using cementless THA with a customized stem and a reinforcement ring. In anatomic X-rays and CT-scan studies of 83 hips with osteoarthritis following DDH, a great individual variability was shown despite the subluxation class considered with a reduced mediolateral and anteroposterior dimensions of the intramedullary femoral canal in all groups. Greater anteversion (ranging from 2 to 80) in all the DDH groups and a femoral neck shaft angle increased only for femora of class II were found. Another group of 116 luxations of the hip was clinically followed. Clinical outcome was found to be not correlated with the severity of luxation. The problems encountered to restore the center of rotation in THA for DDH correlated well with the severity of dislocation. The postoperative limp was correlated with a vertical position of the acetabular component of more than 35 mm from the interteardrop line. Taking into consideration hip revision for stem or acetabular replacement, the cumulative survival rate was 94.7%+/-2.7% at 12 years. Cementless custom stem is certainly a step forward in the future of hip arthroplasty in a young and active population with DDH to probably include in a preoperative and intraoperative computer assisted surgery.