Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, 10 Hyoryeong-ro, Seocho-gu, Seoul, 06698, Republic of Korea.
Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Knee Surg Sports Traumatol Arthrosc. 2019 Apr;27(4):1213-1223. doi: 10.1007/s00167-018-5045-9. Epub 2018 Jul 5.
Posterior-stabilized (PS)-total knee arthroplasty (TKA) can be applied in any of several variations in terms of the tibiofemoral conformity and post-cam mechanism. However, previous studies have not evaluated the effect of the condylar surface radii (tibiofemoral conformity) on wear in a customized PS-TKA. The present study involved evaluating the wear performance with respect to three different conformities of the tibiofemoral articular surface in a customized PS-TKA by means of a computational simulation.
An adaptive computational simulation method was developed that conduct wear simulation for tibial insert to predict kinematics, weight loss due to wear, and wear contours to results. Wear predictions using computational simulation were performed for 5 million gait cycles with force-controlled inputs. Customized PS-TKA designs were developed and categorized as conventional conformity (CPS-TKA), medial pivot conformity (MPS-TKA), and anatomical conformity (APS-TKA). The post-cam design in the customized PS-TKA is identical. We compared the kinematics, contact mechanics, and wear performance.
The findings revealed that APS-TKA exhibited the highest internal tibial rotation relative to other TKA designs. Additionally, the higher contact area led to there being less contact stress although it did not directly affect the wear performance. Specifically, MPS-TKA exhibited the lowest volumetric wear.
The results of the present study showed that tibiofemoral articular surface conformity should be considered carefully in customized PS-TKA design. Different wear performances were observed with respect to different tibiofemoral conformities. Even though APS-TKA exhibited an inferior wear performance compared to MPS-TKA, it proved to be better in terms of kinematics so its functionality may be improved through the optimization of the tibiofemoral articular surface conformity. Additionally, it should be carefully designed since any changes may affect the post-cam mechanism.
后稳定型（PS）全膝关节置换术（TKA）可在胫骨股骨匹配和后凸轮机构的几个变化中应用。然而，以前的研究尚未评估定制 PS-TKA 中髁面半径（胫骨股骨匹配）对磨损的影响。本研究通过计算模拟评估了在定制 PS-TKA 中三种不同胫骨股骨关节面贴合度的磨损性能。
开发了一种自适应计算模拟方法，对胫骨衬垫进行磨损模拟，以预测运动学、由于磨损导致的重量损失以及磨损轮廓的结果。使用计算模拟进行了 500 万次步态周期的磨损预测，采用力控制输入。开发了定制 PS-TKA 设计，并分为常规贴合度（CPS-TKA）、内侧枢轴贴合度（MPS-TKA）和解剖贴合度（APS-TKA）。定制 PS-TKA 中的后凸轮设计相同。我们比较了运动学、接触力学和磨损性能。
研究结果表明，APS-TKA 与其他 TKA 设计相比，表现出最高的内胫骨旋转。此外，较高的接触面积导致接触应力较小，尽管它不会直接影响磨损性能。具体来说，MPS-TKA 表现出最低的体积磨损。
本研究结果表明，在定制 PS-TKA 设计中应仔细考虑胫骨股骨关节面贴合度。不同的胫骨股骨贴合度会导致不同的磨损性能。尽管 APS-TKA 的磨损性能不如 MPS-TKA，但在运动学方面表现更好，因此可以通过优化胫骨股骨关节面贴合度来改善其功能。此外，由于任何变化都可能影响后凸轮机构，因此应谨慎设计。
