不同内翻负荷对大鼠胫股关节生物力学影响的研究

Effect of Different Varus Load on Biomechanics of Tibiofemoral Joint in Rats

目的:研究不同内翻负荷下大鼠胫股关节生物力学特性,探讨胫股关节生物力学的改变诱导膝骨性关节炎的发病机制。方法:采集10例SD大鼠下肢Micro-CT影像,利用Mimics和ANSYS等软件构建大鼠膝关节有限元模型,施加0%,50%和100%内翻负荷下,分析大鼠站立时胫股关节的内外侧腔室最大接触压强和接触面积。利用生物力学测试平台设计相应的膝内翻实验验证与有限元分析结果的一致性,统计学方法采用独立样本t检验。结果:有限元分析和实验结果表明:不同内翻负荷下胫股关节最大接触压强和接触面积变化趋势基本一致。与施加0%体重力内翻负荷相比,施加50%体重力内翻负荷和100%体重力内翻负荷的胫股关节内侧腔室最大接触压强和接触面积随着负荷增大而增大,最大增加了0.53 MPa和1.07 mm2。而外侧腔室最大接触压强和接触面积随着负荷增大而减小,最大减小了0.41 MPa和1.84 mm2。研究结果独立样本t检验表明,内、外腔室最大接触压强P>0.05,接触面积P>0.05,在胫股关节生物力学特性上不具有统计学差异。结论:本研究的大鼠胫股关节模型受到内翻负荷时内侧腔室最大接触压强变化与人类KOA发展过程中的胫股关节最大接触压强变化(0.54 MPa)相似,并随着内翻负荷的增大,软骨磨损概率增加,膝骨性关节炎发病风险也随之增大。研究结果可为胫股关节生物力学诱导膝骨性关节炎的发病机制、临床预防和治疗提供依据。

Objective:To study the biomechanical characteristics of tibiofemoral joint in rats under different varus loads,and to explore the pathogenesis of knee osteoarthritis induced by the biomechanical changes of tibiofemoral joint.Methods:Micro-CT images of the hindlimbs from 10 SD rats were collected,and a finite element model of the rat knee joint was constructed using software such as Mimics and ANSYS to analyse the maximum contact pressure and contact area of the medial and lateral compartments of the tibiofemoral joint when the rats stood up with 0%,50%and 100%internal rotation loads applied.The corresponding knee inversion experiments were designed using the biomechanical test platform to verify the consistency with the finite element analysis results,and the statistical method was an independent samples t-test.Results:The maximum contact pressure and contact area of a tibiofemoral joint under different varus loads were consistent with the finite element analysis and experiment results.Compared with 0%body weight pronation load,the maximum contact pressure and contact area of the medial compartment of tibiofemoral joint under 50%body weight pronation load and 100%body weight pronation load increased with the increase of load,and the maximum increase was 0.53 MPa and 1.07 mm2.However,the maximum contact pressure and contact area of the outer chamber decreased with the increase in load,and the maximum decreased by 0.41 MPa and 1.84 mm2.The independent samples t-test of the findings showed that the maximum contact pressure of the internal and external chambers P>0.05 and the contact area P>0.05 were not statistically different in the biomechanical properties of the tibiofemoral joint.Conclusions:In this study,the maximum contact pressure change of the medial compartment of the rat tibiofemoral joint model under varus load was similar to that of the human tibiofemoral joint during the development of KOA(0.54 MPa).With the increase of varus load,the probability of cartilage wear increased,and the risk of knee osteoarthritis also increased.The results can provide a basis for the pathogenesis,clinical prevention and treatment of knee osteoarthritis induced by tibiofemoral joint biomechanics.