单髁置换胫骨假体后倾角对关节接触应力影响

The Influence from Posterior Inclinations of Tibial Prosthesis on Tibio-Femoral Contact Force after Unicompartmental Knee Arthroplasty

目的 建立活动平台膝关节单髁置换(mobile-bearing unicompartmental knee arthroplasty, MB-UKA)术前、术后膝关节有限元模型,研究MB-UKA胫骨假体后倾角对关节接触应力影响。方法 基于健康受试者计算机断层(computed tomography, CT)及磁共振(magnetic resonance, MR)影像,构建健康膝关节有限元模型,并验证MB-UKA术前、术后模型的有效性。模拟MB-UKA胫骨假体后倾7°手术,将三维运动捕捉系统及力平台相关参数作为有限元模型输入条件,分别计算外侧间室胫骨平台软骨和聚乙烯衬垫的最大接触应力。结果 与现有文献结果进行对比验证表明,健康膝关节和MB-UKA术后膝关节有限元模型计算结果较为合理。MB-UKA术后胫股关节接触应力变化较大,聚乙烯衬垫接触应力远大于对侧间室胫骨平台软骨接触应力。结论 本文所建MB-UKA术前、术后有限元模型较为合理。研究结果为MB-UKA的评估提供了一个可参考的方法。

Objective The finite element models of knee joint before and after mobile-bearing unicompartmental knee arthroplasty(MB-UKA) were established, and the influence from posterior inclinations of tibial prosthesis on contact stress of tibio-femoral joints was studied. Methods Based on computed tomography(CT) and magnetic resonance(MR) images from a healthy subject, the finite element model of healthy knee joint was developed, and the validity of knee joint model before and after MB-UKA was verified. MB-UKA with 7° posterior inclination of tibial component was simulated, and the maximum contact stress of tibial plateau cartilage in lateral compartment and polyethylene insert was calculated based on joint forces obtained by three-dimensional(3D) motion capture system in MB-UKA model. Results The comparison with results from present literatures showed that calculation results of healthy knee joint model and post-MB-UKA knee joint model were reasonable. The maximum contact stress on polyethylene insert after MB-UKA was greater than that on tibial plateau cartilage in lateral compartment. Conclusions The established finite element models before and after MB-UKA were verified.This study provides a referable method for MB-UKA evaluation.