THE EFFECT OF HYDROXYAPATITE COATING ON THE FIXATION OF HIP PROSTHESES - A COMPARISON OF CLINICAL AND RADIOGRAPHIC RESULTS OF HIP-REPLACEMENT IN A MATCHED-PAIR STUDY

The efficacy of a total hip replacement with a hydroxyapatite-coated h ip prosthesis was compared with that of an uncoated, cementless prosth esis of the same type. Preoperatively, there was no difference in the patient's diagnosis, hip score, age, and sex. All operations were perf ormed by one surgeon in a standardized manner. The choice of the impla nt was randomized, and the follow-up period was equal for both types. The implant used was associated with a poor outcome due to a high inci dence of early aseptic loosening. Probably because of a poor initial f ixation, there was a significant difference in the clinical results af ter a short follow-up period when an additional HA layer was used. Acc ording to the patients' pain, migration of the implant, and presence o f a progressive radiolucent line, use of the HA-coated prosthesis led to a significantly better result; however, we also found an increased rate of heterotopic bone formation in the HA-coated group. It was conc luded that the HA coating improves the initial fixation of a hip prost hesis.