轻度与重度骨关节炎膝关节的生物力学行为比较

目的 对比研究轻度与重度膝骨关节炎(knee osteoarthritis, KOA)膝关节的生物力学行为，阐述KOA进展的生物力学机制。方法 分别构建同一患者左侧轻度KOA(KL分级Ⅰ级)与右侧重度KOA(KL分级Ⅳ级)膝关节有限元模型。在材料属性、边界条件、载荷等设定相同的情况下进行有限元分析，比较轻度与重度KOA膝关节半月板、股骨软骨、胫骨软骨的接触面积、接触压及von Mises应力的变化特征。结果 重度KOA膝关节总接触面积和外侧室接触面积大于轻度KOA膝关节，而内侧间室接触面积小于轻度KOA膝关节。重度KOA膝关节半月板、股骨软骨和胫骨软骨上的接触压及von Mises应力峰值均大于轻度KOA膝关节；双膝关节外侧半月板上接触压及von Mises应力峰值均大于内侧半月板，双膝关节股骨软骨与胫骨软骨内侧间室接触压及von Mises应力峰值均大于外侧间室。结论 重度KOA膝关节应力分布不同于轻度KOA,接触面积、接触压和von Mises应力峰值的变化与半月板脱位、软骨缺损等因素相关，生物力学行为和解剖结构的改变促进了KOA进展。

Comparison of Biomechanical Behavior Between Mild and Severe Knee Osteoarthritis

Objective To compare the biomechanical behavior of knee joints with mild and severe knee osteoarthritis (KOA), and to elaborate the biomechanical mechanism of KOA progression. Methods The finite element models of the left mild KOA knee (KL grade I) and the right severe KOA knee joint (KL grade IV) for the same patient were constructed respectively. Under the same setting of material properties, boundary conditions and loads, the change characteristics of knee meniscus, femoral cartilage and tibial cartilage between mild and severe KOA, including contact area, contact pressure and von Mises stress were compared by using finite element analysis. Results The total contact area and lateral compartment of knee joint with severe KOA was larger than that of knee joint with mild KOA, but the contact area of medial compartment was smaller than that of knee joint with mild KOA. The peak contact pressure, von Mises stress on meniscus, femoral cartilage and tibial cartilage of knee joint with severe KOA were higher than those of knee joint with mild KOA. The contact pressure and peak von Mises stress on the lateral meniscus of both knees were greater than those on the medial meniscus, and the contact pressure and peak von Mises stress of the medial compartment between femoral cartilage and tibial cartilage of both knees were greater than those of the lateral compartment. Conclusions The stress distribution of knee joint with severe KOA is different from that of knee joint with mild KOA. The changes of contact area, contact pressure and peak von Mises stress are related to factors such as meniscus dislocation and cartilage defect. The changes of biomechanical behavior and anatomical structure promote the progress of KOA.