Influences of Different Implant Material Combinations on the Stress Distribution of the Foot Following Total Ankle Replacement: a Finite Element Analysis

Abstract Background A proper combination of implant materials for Total Ankle Replacement (TAR) may reduce stress at the implant and the foot. This study aimed to investigate the biomechanical influences for different implant material combinations using the finite element (FE) method. Methods A validated foot model was modified to simulate TAR with the INBONE II ankle system at the second peak ground reaction force. Six types of materials were used (Ceramic, cobalt–chromium–molybdenum alloy (CoCrMo), Titanium alloy (Ti6Al4V), carbon-fiber-reinforced Polyether-ether-ketone (CFR-PEEK), Polyether-ether-ketone (PEEK), and used ultra-high molecular weight polyethylene (UHMWPE)). Results The von Mises stress at the bearing articular surface decreased with implant stiffness. The combination of CFR-PEEK on UHMWPE presented the lowest stress of 14.82 MPa. A low implant stiffness of the talar component, rather than the bearing, relieved the stress at the resected surface of the talus. Conclusions Soft implant material provided a stress reduction at the bearing and adjacent bones. CFR-PEEK seemed to be a good alternative to implant metal components.