EFFECT OF ACETABULAR SHELL OUTER GEOMETRY ON SHELL SEATING AND INITIAL STABILITY

Introduction A majority of the acetabular shells used today are designed to be press-fit into the acetabulum. Adequate initial stability of the press-fit implant is required to achieve biologic fixation, which provides long-term stability for the implant. Amongst other clinical factors, shell seating and initial stability are driven by the interaction between the implant's outer geometry and the prepared bone cavity. The goal of this study was to compare the seating and initial stability of commercially available hemispherical and rim-loading designs. Materials and Methods The hemispherical test group (n=6) consisted of 66mm Trident Hemispherical shells (Stryker, Mahwah NJ) and the rim-loading test group (n=6) consisted of 66mm Trident PSL shells (Stryker, Mahwah NJ). The Trident PSL shell outer geometry is hemispherical at the dome and has a series of normalizations near the rim. The Trident Hemispherical shell outer geometry is completely hemispherical. Both shells are clinically successful and feature ...