Department of Mechanical Engineering, Yozgat Bozok University, Yozgat, Turkey.
BMC Musculoskelet Disord. 2022 Sep 19;23(1):871. doi: 10.1186/s12891-022-05828-2.
The effect of posterior tibial slope on the maximum contact pressure and wear volume of polyethylene (PE) insert were not given special attention. The effects of flexion angle, Anterior-Posterior (AP) Translation, and Tibial slope on the max contact pressure and wear of PE insert of TKR were investigated under loadings which were obtained in cadaver experiments by using Archard's wear law. This study uses not only loads obtained from cadaver experiments but also dynamic flexion starting from 0 to 90 degrees.
Wear on knee implant PE insert was investigated using a 2.5 size 3 dimensional (3D) cruciate sacrificing total knee replacement model and Finite Element Method (FEM) under loadings and AP Translation data ranging from 0 to 90 flexion angles validated by cadaver experiments. Two types of analyses were done to measure the wear effect on knee implant PE insert. The first set of analyses included the flexion angles dynamically changing with the knee rotating from 0 to 90 angles according to the femur axis and the transient analyses for loadings changing with a certain angle and duration.
It is seen that the contact pressure on the PE insert decreases as the cycle increases for both Flexion and Flexion+AP Translation. It is clear that as the cycle increases, the wear obtained for both cases increases. The loadings acting on the PE insert cannot create sufficient pressure due to the AP Translation effect at low speeds and have an effect to reduce the wear, while the effect increases with the wear as the cycle increases, and the AP Translation now contributes to the wear at high speeds. It is seen that as the posterior tibial slope angle increases, the maximum contact pressure values slightly decrease for the same cycle.
This study indicated that AP Translation, which changes direction during flexion, had a significant effect on both contact pressure and wear. Unlike previous similar studies, it was seen that the amount of wear continues to increase as the cycle increases. This situation strengthens the argument that loading and AP Translation values that change with flexion shape the wear effects on PE Insert.
胫骨后倾角对聚乙烯（PE）衬垫的最大接触压力和磨损体积的影响并未受到特别关注。本研究采用阿查德磨损定律，根据尸体实验中获得的加载条件，研究了膝关节置换术中胫骨后倾角、屈曲角度、前后（AP）平移对 TKR 中 PE 衬垫最大接触压力和磨损的影响。本研究不仅使用了尸体实验中获得的载荷，还使用了从 0 度到 90 度的动态屈曲。
使用 2.5 尺寸的 3 维（3D）牺牲十字韧带全膝关节置换模型和有限元法（FEM），在尸体实验验证的 0 至 90 度屈曲角度范围内的载荷和 AP 平移数据下，对膝关节植入物 PE 衬垫的磨损进行了研究。进行了两种类型的分析来测量膝关节植入物 PE 衬垫的磨损效果。第一组分析包括膝关节根据股骨轴从 0 度到 90 度动态旋转时，屈伸角度随时间的变化以及随一定角度和持续时间变化的载荷的瞬态分析。
结果表明，在屈伸和屈伸+AP 平移两种情况下，随着循环次数的增加，PE 衬垫上的接触压力减小。很明显，随着循环次数的增加，两种情况下的磨损量都增加。在低速时，AP 平移对作用在 PE 衬垫上的载荷的影响不能产生足够的压力，从而起到减少磨损的作用，而随着循环次数的增加，这种影响会增加，AP 平移现在对高速时的磨损有影响。结果表明，随着胫骨后倾角的增加，在相同的循环次数下，最大接触压力值略有下降。
本研究表明，在屈曲过程中改变方向的 AP 平移对接触压力和磨损都有显著影响。与之前的类似研究不同，随着循环次数的增加，磨损量持续增加。这种情况进一步证实了加载和随屈曲形态变化的 AP 平移会对 PE 衬垫的磨损产生影响的观点。
