Yang Huizhou, Behnam Yashar, Clary Chadd, Rullkoetter Paul J
Center for Orthopaedic Biomechanics, University of Denver, Denver, CO, 80208, USA.
Center for Orthopaedic Biomechanics, University of Denver, Denver, CO, 80208, USA.
J Mech Behav Biomed Mater. 2022 Dec;136:105507. doi: 10.1016/j.jmbbm.2022.105507. Epub 2022 Oct 5.
The initial fixation of cementless tibial trays after total knee arthroplasty is critical to ensure bony ingrowth and long-term fixation. Various fixed-bearing implant designs that utilize different fixation features, surface coatings, and bony preparations to facilitate this initial stability are currently used clinically. However, the role of tibiofemoral conformity and the effect of different tray fixation features on initial stability are still unclear. This study assessed the implant stability of two TKA designs during a series of simulated daily activities including experimental testing and corresponding computational models. Tray-bone interface micromotions and the porous area ideal for bone ingrowth were investigated computationally and compared between the two designs. The isolated effect of femoral-insert conformity and fixation features on the micromotion was examined separately by virtually exchanging design features. The peak interface micromotions predicted were at least 47% different for the two designs, which was a combined result of different femoral-insert conformity (contributed 79% of the micromotion difference) and fixation features (21%). A more posterior femoral-insert contact due to lower tibiofemoral conformity in a force-controlled simulation significantly increased the micromotion and reduced the surface area ideal for bone ingrowth. The maximum difference in peak micromotions caused by only changing the fixation features was up to 33%. Overall, the moment arm from the insert articular contact point to the anterolateral tray perimeter was the primary factor correlated to peak and average micromotion. Our results indicated that tray-bone micromotion could be minimized by centralizing the load transfer and optimizing the fixation features.
全膝关节置换术后非骨水泥胫骨托的初始固定对于确保骨长入和长期固定至关重要。目前临床上使用了各种固定承重植入物设计，这些设计利用不同的固定特征、表面涂层和骨准备来促进这种初始稳定性。然而，胫股关节匹配度的作用以及不同托盘固定特征对初始稳定性的影响仍不清楚。本研究在一系列模拟日常活动中评估了两种全膝关节置换设计的植入物稳定性，包括实验测试和相应的计算模型。通过计算研究了托盘-骨界面的微动以及适合骨长入的多孔区域，并在两种设计之间进行了比较。通过虚拟交换设计特征，分别研究了股骨假体匹配度和固定特征对微动的单独影响。两种设计预测的峰值界面微动至少相差47%，这是不同股骨假体匹配度（占微动差异的79%）和固定特征（21%）共同作用的结果。在力控制模拟中，由于胫股关节匹配度较低导致股骨假体接触点更靠后，显著增加了微动并减少了适合骨长入的表面积。仅改变固定特征引起的峰值微动最大差异高达33%。总体而言，从假体关节接触点到前外侧托盘周边的力臂是与峰值和平均微动相关的主要因素。我们的结果表明，通过集中载荷传递和优化固定特征，可以将托盘-骨微动降至最低。
