The influence of simulator input conditions on the wear of total knee replacements: An experimental and computational study.

The influence of simulator input conditions on the wear of total knee replacements: An experimental and computational study.

Advancements in knee replacement design, material and sterilisation processes have provided improved clinical results. However, surface wear of the polyethylene leading to osteolysis is still considered the longer-term risk factor. Experimental wear simulation is an established method for evaluating the wear performance of total joint replacements. The aim of this study was to investigate the influence of simulation input conditions, specifically input kinematic magnitudes, waveforms and directions of motion and position of the femoral centre of rotation, on the wear performance of a fixed-bearing total knee replacement through a combined experimental and computational approach. Studies were completed using conventional and moderately cross-linked polyethylene to determine whether the influence of these simulation input conditions varied with material. The position of the femoral centre of rotation and the input kinematics were shown to have a significant influence on the wear rates. Similar trends were shown for both the conventional and moderately cross-linked polyethylene materials, although lower wear rates were found for the moderately cross-linked polyethylene due to the higher level of cross-linking. The most important factor influencing the wear was the position of the relative contact point at the femoral component and tibial insert interface. This was dependent on the combination of input displacement magnitudes, waveforms, direction of motion and femoral centre of rotation. This study provides further evidence that in order to study variables such as design and material in total knee replacement, it is important to carefully control knee simulation conditions. This can be more effectively achieved through the use of displacement control simulation.

膝关节置换设计、材料和灭菌工艺的进步带来了更好的临床效果。然而，聚乙烯的表面磨损导致骨溶解仍然被视为长期风险因素。实验性磨损模拟是评估全关节置换磨损性能的一种成熟方法。本研究的目的是通过实验和计算相结合的方法，研究模拟输入条件，特别是输入运动学参数大小、波形、运动方向以及股骨旋转中心位置对固定承重全膝关节置换磨损性能的影响。使用常规聚乙烯和中度交联聚乙烯进行研究，以确定这些模拟输入条件的影响是否因材料而异。结果表明，股骨旋转中心位置和输入运动学参数对磨损率有显著影响。常规聚乙烯和中度交联聚乙烯材料显示出相似的趋势，不过由于中度交联聚乙烯的交联程度较高，其磨损率较低。影响磨损的最重要因素是股骨部件和胫骨衬垫界面处的相对接触点位置，这取决于输入位移大小、波形、运动方向以及股骨旋转中心的组合。本研究进一步证明，为了研究全膝关节置换中的设计和材料等变量，仔细控制膝关节模拟条件非常重要。通过使用位移控制模拟可以更有效地实现这一点。