MECHANICAL FAILURE OF THE FEMORAL COMPONENT IN CEMENTED TOTAL HIP-REPLACEMENT - A FINITE-ELEMENT EVALUATION

The quality of cementation is of paramount importance for the long-ter m clinical outcome in cemented total hip replacement. Four ''modes of failure'' have been differentiated by various authors and correlated w ith the clinical findings. A finite element analysis was performed to simulate an ideally cemented femoral stem-type prosthesis as well as f ailure modes III (proximal anchorage of implant only) and IV (Distal a nchorage of implant only). While failure mode III produces a stress di stribution at the bone/acrylic cement interface, which is similar to t he ideally cemented prosthesis, failure mode type IV leads to a hazard ous rise of the interface stresses. This correlates well with the clin ical findings given in the literature, thus validating the computer si mulation used. Distal cementation only of a stem-type femoral componen t in total hip replacement should definitely be avoided.