Abstract
Component migration after THR is directly correlated with loosening and reported to be predictive for the long-term survival rate. In literature, four different patterns of stem-migration are reported. Likewise, periprothetic osteolytic zones indicate the risk of loosening and revision in the further course. Nevertheless, little is known about the distinguish migration behaviour between cemented and uncemented stems throughout the process of loosening. The aim of this study was to evaluate the influence of cementing on migration behaviour of loose femoral components after THR. A total of 207 stem-revisions have been performed at our institution between 1996 and 2001. Only patients with aseptic loosening after primary hip replacements were included in the present study. Thus, 75 patients had to be excluded due to other reasons for loosening. Migration analysis was done with the EBRA-FCA method (Einzel-Bild-Röntgen-Analyse, Femoral Component Analysis). In addition, a radiographic analysis was performed following Gruen et al. For migration analysis, a minimum of four x-rays per series are required. Hence, another 72 patients had to be excluded due to insufficient x-ray documentation. A total of 40 cemented (Group A) and 20 uncemented (Group B) femoral components could be analysed. There were no significant differences between the two groups with regard to age (60 years for Group A, 56 years for Group B), gender or side. Mean number of radiographs per series was 7.2 for Group A and 7.9 for Group B respectively. Mean stem survival differed between the two groups (11.3 years for Group A and 8.8 years for Group B), but without statistical significance (T-Test: p> 0.05). Differences in migration behaviour and distinct types of loosening after cemented and uncemented total hip replacement will be presented.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
