BACKGROUND:The post-cam mechanism in the posterior-stabilized (PS) implant plays an important role, such as durability and kinematic performances, in total knee arthroplasty (TKA). OBJECTIVE:The purpose of this study was to evaluate the difference in the kinematics and contact stress of five post-cam designs, which are flat-and-flat, curve-and-curve (concave), curve-and-curve (concave and convex), helical, and asymmetrical post-cam designs, using three-dimensional finite element models. METHODS:We designed the post-cam model with five different geometries. The kinematics, contact stress, and contact area were evaluated in the five post-cam designs under gait cycle loading conditions using the finite element method. RESULTS:There were no differences in the contact stress and area on the tibial insert in all designs. The largest internal rotation was shown in the swing phase for the helical design, and the largest tibial posterior translation was observed for the curve-and-curve (concave) design. The curve-and-curve (concave) design showed the lowest contact stress and the largest posterior tibial translation during the gait cycle. CONCLUSIONS:Considering the kinematics and contact stress, we found that the curve-and-curve (concave) design was more stable than other designs. From the results, we found the important factors of TKA implant considering stability and kinematics.

中文翻译：

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后凸轮设计对后稳定全膝关节置换术运动学和接触应力的影响

背景：后稳定（PS）植入物中的后凸轮机构在全膝关节置换术（TKA）中起着重要作用，例如耐久性和运动学性能。目的：本研究的目的是评估五种后凸轮设计的运动学和接触应力的差异，这些设计是平平、曲线和曲线（凹）、曲线和曲线（凹和）。凸）、螺旋和非对称后凸轮设计，使用三维有限元模型。方法：我们设计了具有五种不同几何形状的后凸轮模型。在步态循环加载条件下，使用有限元方法评估了五种后凸轮设计中的运动学、接触应力和接触面积。结果：所有设计中胫骨插入物的接触应力和面积均无差异。螺旋设计的摆动期显示最大的内旋，曲线和曲线（凹）设计观察到最大的胫骨后移。曲线和曲线（凹面）设计在步态周期中显示出最低的接触应力和最大的胫骨后平移。结论：考虑到运动学和接触应力，我们发现曲线和曲线（凹面）设计比其他设计更稳定。从结果中，我们发现了考虑稳定性和运动学的TKA种植体的重要因素。结论：考虑到运动学和接触应力，我们发现曲线和曲线（凹面）设计比其他设计更稳定。从结果中，我们发现了考虑稳定性和运动学的TKA种植体的重要因素。结论：考虑到运动学和接触应力，我们发现曲线和曲线（凹面）设计比其他设计更稳定。从结果中，我们发现了考虑稳定性和运动学的TKA种植体的重要因素。