The importance of geometry and thickness for the conception of a new patellofemoral prosthesis

Abstract

One of the major reasons for the failure of currently available knee implants is the stress shielding effect. In loading situations, the bone is less requested, so the rate of bone remodeling decreases. The purpose for this work was to analyze the influence of the geometry and rigidity of the bone-implant interface on the stress shielding effect and on the stability of the prosthesis, applying the Finite Element Method. The results showed that elastic strain is lower on bone areas close to the studied models of patellofemoral prosthesis, on the period after the implantation. Later on, bone rupture by fatigue may occur, due to high strain, particularly on the models with fixation pins for the prosthesis. Moreover, contact analyses showed that stability is best promoted without fixation pins.