[Zweymüller's Endoprosthesis in Total Hip Arthroplasty for Postdysplastic Osteoarthritis.]

The authors evaluated a group of 224 patients, 148 females and 76 males, the average age 56 (range 39-75) in which total hip arthroplasty was performed for postdysplastic osteoarthritis by means of Zweymüller's cementless total endoprosthesis. In the period from September 1995 until December 1998 in total 236 hip joints were operated on, of which 12 bilaterally. According to the Crowe classification 76 of 236 hip joints were of Degree I, 149 of Degree II, 11 of Degree III and 0 of Degree IV. Different types of osteotomies were performed previously in 16 hip joints. During preoperative planning 3D CT scanning and multiplanar reconstruction was used in 92 patients of Degrees II and III after Crowe with the aim to evaluate the quantity of the hip joint bone and the possibility of the selection of the size particularly of the acetabular component. Due to the non-compliance of x-ray criteria Zweymüller's total hip arthroplasty was not recommended in 4 patients. In all cases the anterolateral approach was used without osteotomy of the greater trochanter as well as the cup medial translation technique. Autografts were applied in 30 %. The size of acetabular and femoral components was in indirect proportion to the degree of dysplasia. Two hundred and twenty three patients showed up for the check. Evaluation was based on the Harris Hip Score. The evaluation score during the check as compared to that prior to the operation improved on average by 100 %. Radiographs showed osteointegration in both components. Resorption of autografts was recorded in 5 cases (1,9 %). Revision surgery, replacement of implants or removal of the endoprosthesis was not performed in any of the cases. Cementless Zweymüller's endoprosthesis is a very suitable type of implant for the solution of postdysplastic osteoarthritis. It ensures primarily a very good stability of both components and a timely secondary osteointegration. Key words: THR, postdysplastic osteoarthritis, cementless endoprosthesis, cup medial translation technique, 3D CT scan.