基于CT和MRI膝关节有限元模型建立与不同载荷下生物力学特性分析

Establishment of finite element model of knee joint based on CT and MRI and analysis of biomechanical characteristics under different loads

基于CT和MRI图像数据建立膝关节有限元模型,采用六面体网格对不同载荷系统下人体膝关节生物力学特性进行研究,并进行有效性验证。建立膝关节有限元模型包括:股骨、胫骨、髌骨、腓骨、股骨软骨、胫骨软骨、腓骨软骨、半月板、前后交叉韧带、内外侧副韧带、髌韧带和股四头肌腱等。对膝关节施加1 kN轴向压缩载荷、134 N后向抽屉力和5、10、15 N∙m内翻力矩和外翻力矩,分析膝关节内软骨和半月板的接触应力和接触面积,股骨内外翻倾角以及位移变化情况。在1 kN压缩载荷和134 N抽屉力作用下,股骨软骨、内外侧半月板和内外侧胫骨软骨的接触应力峰值分别为4.47、3.25、2.83、2.70、2.53 MPa,Von Mises应力峰值分别为2.22、2.44、2.25、2.07、1.64 MPa。股骨相对胫骨前向位移为4.19 mm。施加5、10、15 N∙m内翻和外翻力矩时,股骨内翻和外翻倾角分别为3.49°、4.48°、4.91°和3.22°、3.62°、4.01°。随着力矩的线性增大,膝关节各组成部分的应力呈非线性变化趋势。膝关节软骨、半月板和韧带的研究结果符合其生物力学特性,与前人数值分析和实验研究结果相一致,可为临床膝关节生理病理分析和治疗提供一定的理论依据。

Based on CT and MRI image data,a finite element model of the knee joint is established,and hexahedral mesh is used to analyze the biomechanical characteristics of human knee joint under different loads,thereby verifying the validity of the model.The established knee joint finite element model includes femur,tibia,patella,fibula,femoral cartilage,fibula cartilage,meniscus,anterior and posterior cruciate ligament,medial and lateral collateral ligament,patellar ligament and femoral quadriceps tendon.After the knee joint is applied with 1 kN axial compression load,134 N in posterior drawer test,and 5,10,15 N·m varus and valgus torques,the contact stress and contact area of the internal cartilage and the meniscus of the knee joint,femoral varus angles and valgus angles are analyzed,and the displacement of the knee joint is measured.Under 1 kN compression load and 134 N in drawer test,the peak contact stresses of femur cartilage,medial and lateral meniscus,and medial and lateral tibial cartilage are 4.47,3.25,2.83,2.70 and 2.53 MPa,respectively,with peak Von Mises stresses of 2.22,2.44,2.25,2.07 and 1.64 MPa,respectively.The displacement of femur relative to tibia is 4.19 mm.When applying 5,10 and 15 N·m varus and valgus torques,femoral varus and valgus angles are 3.49°,4.48°,4.91°,and 3.22°,3.62°,4.01°,respectively.With the linear increase of torque,the stress of each component of the knee joint presents a nonlinear change trend.The analysis results of knee articular cartilage,meniscus and ligaments are in accordance with their biomechanical properties,which is consistent with the previous results of numerical analysis and experimental studies.The established model can provide a certain theoretical basis for the physiological and pathological analyses on knee joint and its treatment research.