An experimental protocol was developed to investigate the effects of the loading condition associated with a high-risk sporting maneuver on the surface wear on the TKR, compared to that with a typical gait cycle. The ISO force-control load profiles for wear testing, and the loading condition representing a typical cutting maneuver, were used to drive a force-controlled dynamic simulation using the existing Lanovaz Model. The resulting kinematic joint data were extracted from the model, and used as inputs for the physical wear test. A displacement-controlled joint simulator was used, and the measured kinematic profiles were then used to drive the Lanovaz model, this time in displacement-control mode. This simulation was used to predict the kinematic conditions on the bearing surface of the TKR, and the consequent effects on the wear characteristics. The results of the physical wear test were compared to the model predictions, for the gait simulation, and the simulation of the cutting maneuver.

While the overall wear area was similar for both cases, the patterns of wear were different. Predicted kinematic conditions, rolling and sliding, correlated to different observed surface features. Regions of rolling were characterized by longitudinal ridges and micro-delamination, while regions of sliding were characterized by transverse ripples and directional scratches. The medial condyle of the ISO tibia was dominated by rolling, and that of the CUT tibia was dominated by sliding. Similarly, on the lateral condyle, the ISO tibia was characterized mainly by rolling and the CUT tibia was characterized by sliding. The investigation highlighted the need to characterize the wear features resulting from different kinematic conditions, and to further develop the long-term consequences of these features. It presented a framework for investigating the effects of simulated high-risk sport maneuvers on the wear of polyethylene in TKRs