Finite element modeling of the glenoid component: Effect of design parameters on stress distribution.

A two-dimensional plane stress model of the natural glenoid was developed with finite element analysis to observe the stress distributions under various loading conditions. Different glenoid prosthetic designs were evaluated with the use of the finite element model in an attempt to elucidate key features for an improved design. These included a keel model, a stair-stepped model, and a wedge model. In addition to the evaluation of these designs, different interfaces were introduced to simulate various environments of the prostheses, and different material combinations were studied. Based on the finite element analysis, the following design parameters were found to be important: (1) an all-polyethylene implant appears to provide a more physiologic stress distribution for nonaxial loads if no soft tissue is present; (2) the presence of a soft-tissue layer causes higher stresses; (3) the stair-stepped and wedge models produced a more natural stress distribution compared with the keel design; and (4) screw orientation was not a significant design parameter.