Abstract
Aims: The purpose of this study was to assess the effect of changes in peripheral attachment on stresses and displacements at the liner-shell interface. Methods: Three dimensional þnite element models were constructed of two acetabular cup designs for a liner with a 32 mm inner diameter, a liner thickness of 5 mm, and a shell thickness of 4 mm. An additional set of models was constructed with a 28 mm head diameter, corresponding to a liner thickness of 7 mm. 16 sequential quasistatic loading steps were used to describe the stance phase of a patientñs gait cycle. Results: Changes in the design had a larger inßuence on the backside relative motion during the gait cycle than load magnitude. However, changes in the design had a smaller inßuence on the backside contact stress, von Mises stress, or radial extrusion into screw holes. Reduction in head size from 32 to 28 mm diameter resulted in a slight decrease in screw hole extrusion. Conclusions: In this study, changes in the acetabular cup design, including screw hole placement and increased peripheral interlocking, were shown to decrease relative motion at the liner-shell interface, but the peak liner-shell contact stresses, backside von Mises stresses, and radial screw hole extrusion were less signiþcantly changed.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
