Results of the uncemented total hip arthroplasty in avascular necrosis of the femoral head

Aim of the study: The results from 56 patients with osteonecrosis of the femoral head who underwent 66 uncemented total hip replacements were analyzed and compared with current reports in the literature on cemented endoprosthesis. Methods: In the retrospective study in 30 of those cases the Zweymuller and in 25 cases the HA-coated ABG prosthesis were used. In addition the results of 11 patients with a polyethylene Endler cup in combination with a Zweymuller stem are presented. The mean age at surgery was 48 years, the mean follow-up was 5.9 years. Clinical examination, registration of the Merle d'Aubigne score and a radiological examination were performed. Results: The clinical results did not show any differences between the used prostheses. A more favourable outcome with regard to the Merle d'Aubigne score was demonstrated for the Zweymuller and ABG prostheses. No loosening of the stem was found. Revision as a consequence of aseptic loosening of the acetabular component was done in 7,5 % (27,3 % of the Endler cups and 8 % of the ABG cups). 20% of the patients with an ABG prosthesis showed acetabular osteolysis of various degrees. This seems to be correlated with an increased polyethylene wear. Conclusion: Recent reports in the literature about a favourable outcome in uncemented total hip arthroplasty in osteonecrosis of the femoral head can be confirmed. The unsatisfactory results of the Endler cup indicate that established types of endoprostheses should be preferred.