Radboud University Medical Center, Radboud Institute for Health Sciences, Orthopaedic Research Lab, Nijmegen, the Netherlands.
Aesculap AG, Research & Development, Tuttlingen, Germany.
J Mech Behav Biomed Mater. 2021 Jun;118:104435. doi: 10.1016/j.jmbbm.2021.104435. Epub 2021 Mar 4.
Cementless total knee arthroplasty (TKA) implants rely on interference fit to achieve initial stability. However, the optimal interference fit is unknown. This study investigates the effect of using different interference fit on the initial stability of tibial TKA implants. Experiments were performed on human cadaveric tibias using a low interference fit of 350 μm of a clinically established cementless porous-coated tibial implant and a high interference fit of 700 μm. The Orthoload peak loads of gait and squat were applied to the specimens with a custom-made load applicator. Micromotions and gaps opening/closing were measured at the bone-implant interface using Digital Image Correlation (DIC) in 6 regions of interest (ROIs). Two multilevel linear mixed-effect models were created with micromotions and gaps as dependent variables. The results revealed no significant differences for micromotions between the two interference fits (gait p = 0.755, squat p = 0.232), nor for gaps opening/closing (gait p = 0.474, squat p = 0.269). In contrast, significant differences were found for the ROIs in the two dependent variables (p < 0.001), where more gap closing was seen in the posterior ROIs than in the anterior ROIs during both loading configurations. This study showed that increasing the interference fit from 350 to 700 μm did not influence initial stability.
非骨水泥全膝关节置换（TKA）植入物依靠过盈配合来实现初始稳定性。然而，最佳的过盈配合量尚不清楚。本研究旨在探讨不同过盈配合量对胫骨 TKA 植入物初始稳定性的影响。采用临床已建立的非骨水泥多孔涂层胫骨植入物的 350μm 低过盈配合和 700μm 高过盈配合，在人体尸体胫骨上进行实验。使用定制的加载器将步态和深蹲的 Orthoload 峰值载荷施加到标本上。在 6 个感兴趣区域（ROI）使用数字图像相关（DIC）测量骨-植入物界面的微位移和间隙开合。使用两个多级线性混合效应模型，将微位移和间隙作为因变量。结果表明，两种过盈配合之间的微位移没有显著差异（步态 p=0.755，深蹲 p=0.232），间隙开合也没有显著差异（步态 p=0.474，深蹲 p=0.269）。相反，两个因变量的 ROI 存在显著差异（p<0.001），在两种加载配置下，后区 ROI 的间隙闭合量大于前区 ROI。本研究表明，将过盈配合从 350μm 增加到 700μm 不会影响初始稳定性。
