Standzeitverkürzende Patientencharakteristika und Protheseneigenschaften von aseptisch gelockerten Hüftendoprothesen

Different types of prostheses and individual patient related characteristics were looked at with regard to their influence on the survival time of hip implants. 150 changes of total hip endoprostheses due to aseptic loosening were retrospectively analyzed with regard to existing osseous periprosthetic bone defects (DeLee - Gruen.-.Zone classification). The shape of the prostheses, the fixation techniques, the materials of the individual components, the number of revisions as well as sex, weight and age of the patients were taken into account as influential factors and evaluated separately for stems and cups. Results: With regard to the femoral components cemented prostheses had a longer survival time than the cementless implants. Anatomic stems had a higher survival time than straight stems. Five stem types were closer looked at Charnley - Müller Curved Stem - SP II Lubinus, - Müller Straight Stem and ABG. Their respective survival times differ in this study significantly with 17,2 - 13,4 - 12,5 - 10,5 - and 5,6 years. With regard to the acetabular components cementless Press-Fit Cups yielded the best results with 12 years survival time, followed by cemented PE-Cups (11years) and Screwing Rings (10 years). With regard to revisions primary revisions had an average survival time for the femoral components of 12 years and 11 years for the acetabular component. In the case of higher order revisions the survival time varies between 7 to 7,5 years. The PE-wear was dependent on the wear couple (Metal-PE greater than Ceramic-PE), the cup position and the survival time of the implant (longer than 10 years). Patients with an implantation age of less than 50 years showed a significant occurrence of premature symptomatic loosening. The various types of prostheses showed a different defect distribution pattern in the periprosthetic bone. Conclusions: With regard to the femoral components cementless implants had in average a lower survival time than the cemented ones, whereas in the case of the acetabular components cementless Press-Fit cups yielded better results than cemented ones. The difference between the various types of prostheses were significant