Finite element analysis of acetabular wear. Validation, and backing and fixation effects.

A two-phase investigation was undertaken to study computational performance aspects of a recently developed finite element formulation that has shown promise in the study of design related influences on total hip arthroplasty wear. In the first phase, computational model predictions were evaluated against directly corresponding physical wear measurements performed in a biaxial rocking hip simulator. The discrepancy between the predictions and the measurements was approximately 4.1%. In the second phase, a bony support bed was introduced to supersede the model's previous simplifying assumption of rigid support at the cup backing. Other factors being equal, computed wear rates differed negligibly for three very different cup backing and fixation modalities studied with the new bony bed support condition, and for two individual cups studied with bony bed support versus the rigid backing support simplification.