Background. Wear-related failures and instabilities are frequent failure mechanisms of total knee replacements. High-conforming\ndesigns may provide additional stability for the joint. This study analyzes the effects of a ligamentous insufficiency on the stability\nand the wear behavior of a high-conforming knee design. Methods. Two simulator wear tests were performed on a high-conforming\ntotal knee replacement design. In the first, a ligamentous-stable knee replacement with a sacrificed anterior cruciate ligament\nwas simulated. In the second, a ligamentous-unstable knee with additionally insufficient posterior cruciate ligament and medial\ncollateral ligament was simulated. Wear was determined gravimetrically and wear particles were analyzed. Implant kinematics\nwas recorded during simulation. Results. Significantly higher wear rates (P ? 0.001) were observed for the unstable knee\n(14.58 �± 0.56mg/106 cycles) compared to the stable knee (7.97 �± 0.87mg/106 cycles). A higher number of wear particles with only\nsmall differences in wear particle characteristics were observed. Under unstable knee conditions, kinematics increased significantly\nfor translations and rotations (P ? 0.01). This increase was mainly attributed to higher tibial posterior translation and internal\nrotations. Conclusion. Higher kinematics under unstable test conditions is a result of insufficient stabilization via implant design.\nDue to the higher kinematics, increased wear was observed in this study.
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