Three dimensional shape optimization of total knee replacements for reduced wear

This paper presents the design optimization of a total knee replacement (TKR) using a parametric three-dimensional finite element (FE) model, considering wear of the ultra high molecular weight polyethylene (UHMWPE) insert. A framework has been developed to generate three-dimensional FE models of the femoral component and UHMWPE insert of a TKR design in a batch mode process, then simulate an ISO standard TKR wear test. A modified version of Archard’s wear model calculates abrasive wear as a function of contact pressure, sliding distance and an experimentally determined wear factor. The UHMWPE wear was reduced by modifying the contact geometry of both components in the frontal and sagittal planes. Wear was reduced by 18.5%, from 55.248 to 45.013 mm3 per year by reducing the radii of curvature of the femoral condyles in the sagittal planes, increasing the radii in the frontal plane, and reducing conformity between the implant components.