Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, USA.
J Biomech. 2011 May 17;44(8):1507-13. doi: 10.1016/j.jbiomech.2011.03.012. Epub 2011 Mar 30.
Though changes in normal joint motions and loads (e.g., following anterior cruciate ligament injury) contribute to the development of knee osteoarthritis, the precise mechanism by which these changes induce osteoarthritis remains unknown. As a first step toward identifying this mechanism, this study evaluates computational wear simulations of a patellofemoral joint specimen wear tested on a knee simulator machine. A multibody dynamic model of the specimen mounted in the simulator machine was constructed in commercial computer-aided engineering software. A custom elastic foundation contact model was used to calculate contact pressures and wear on the femoral and patellar articular surfaces using geometry created from laser scan and MR data. Two different wear simulation approaches were investigated--one that wore the surface geometries gradually over a sequence of 10 one-cycle dynamic simulations (termed the "progressive" approach), and one that wore the surface geometries abruptly using results from a single one-cycle dynamic simulation (termed the "non-progressive" approach). The progressive approach with laser scan geometry reproduced the experimentally measured wear depths and areas for both the femur and patella. The less costly non-progressive approach predicted deeper wear depths, especially on the patella, but had little influence on predicted wear areas. Use of MR data for creating the articular and subchondral bone geometry altered wear depth and area predictions by at most 13%. These results suggest that MR-derived geometry may be sufficient for simulating articular cartilage wear in vivo and that a progressive simulation approach may be needed for the patella and tibia since both remain in continuous contact with the femur.
虽然正常关节运动和负荷的变化（例如前交叉韧带损伤后）会导致膝关节骨关节炎的发展，但这些变化诱发骨关节炎的确切机制尚不清楚。作为确定该机制的第一步，本研究评估了在膝关节模拟器机器上进行磨损测试的髌股关节标本的计算磨损模拟。在商业计算机辅助工程软件中构建了安装在模拟器机器中的标本的多体动力学模型。使用自定义弹性基础接触模型，使用来自激光扫描和磁共振数据创建的几何形状计算股骨和髌骨关节表面的接触压力和磨损。研究了两种不同的磨损模拟方法——一种是在 10 个单周期动态模拟的序列中逐渐磨损表面几何形状（称为“渐进”方法），另一种是使用单个单周期动态模拟的结果突然磨损表面几何形状（称为“非渐进”方法）。渐进方法结合激光扫描几何形状再现了股骨和髌骨的实验测量磨损深度和面积。成本较低的非渐进方法预测了更深的磨损深度，特别是在髌骨上，但对预测的磨损面积影响不大。使用磁共振数据创建关节和软骨下骨几何形状最多可将磨损深度和面积预测改变 13%。这些结果表明，磁共振衍生的几何形状可能足以模拟体内关节软骨的磨损，并且可能需要渐进模拟方法来模拟髌骨和胫骨，因为它们都与股骨保持连续接触。
