有限元法预测运动护膝在不同运动状态下对膝关节韧带的影响

Finite element method for predicting the effect of sports knee brace on knee ligaments under different sports conditions

背景:膝关节韧带是维持膝关节运动稳定性的重要组成部分,在人体运动过程中极易受到损伤,运动护膝常用于预防膝关节运动损伤,但其防护性能未能明确。目的:建立健康成年人的膝关节有限元模型及运动护膝模型,运用有限元法预测运动护膝在不同运动状态下对膝关节韧带的影响,以Von Mises等效应力为观察指标,探讨不同材料运动护膝的防护性能。方法:以1名男性健康志愿者的CT影像为数据来源,利用Mimics、Solidworks、Abaqus等软件获得膝关节有限元模型及运动护膝模型;以股骨内外髁中点为参考点施加后向134 N集中力,模拟临床前抽屉实验,获取股骨相对位移及主要韧带的生物力学响应,验证膝关节模型的有效性;给运动护膝施加位移载荷,模拟膝关节直立位穿着护膝的状态,并与服装压力测试结果进行对比,验证膝关节-护膝模型的有效性;分别在无护膝和两种不同材料护膝作用下模拟膝关节屈曲0°,30°,60°运动,分析不同载荷下前交叉韧带、后交叉韧带、内侧副韧带及外侧副韧带的应力应变情况。结果与结论:(1)在0°,30°,60°屈曲角度下,并且施加320 N垂直压缩力及134 N股骨后向推力后,相较于裸膝,穿着两种不同材料的运动护膝使得前交叉韧带的峰值应力在0°和30°有所降低,但在屈曲60°状态下峰值应力有所上升;后交叉韧带在屈曲0°时的峰值应力有所上升,在30°和60°状态下的峰值应力有所降低;内侧副韧带和外侧副韧带在0°,30°,60°的峰值应力均有所降低。(2)结论:不同材料的运动护膝能在一定程度上对膝关节韧带起到防护作用,但在特定角度下会对前交叉韧带和后交叉韧带产生额外的负荷,该研究结果对膝关节韧带的生物力学研究、运动损伤防护及运动护膝的设计与生产等具有积极意义。

BACKGROUND:Knee ligaments are an important part of maintaining the stability of knee joint movement,which is very vulnerable to injury during exercise,and sports knee braces are often used to prevent knee injuries,but their protective performance is not clear.OBJECTIVE:A finite element model of the knee joint of a healthy adult and a sports knee brace model were established.The finite element method was used to predict the effect of the sports knee brace on the knee joint ligament under different movement states so as to observe the protective performance of different knee braces using Von Mises equivalent stress as the observation index.METHODS:Using CT medical images of one male health volunteer as the data source,Mimics,Solidworks,and Abaqus software were used to obtain the finite element model of the knee joint and the sports knee brace model.The median epicenter of the femur and the medial condyle was set as the reference point to apply backward 134 N concentration force to the point,to simulate the preclinical drawer experiment,to obtain the biomechanical response of the femur relative displacement and major ligaments,and to verify the effectiveness of the knee model.The displacement load was applied to the sports knee brace,to simulate the state of wearing the knee brace in an upright position and to compare with the clothing stress test results to verify the effectiveness of the knee joint-knee brace model.The 0°,30°and 60°movements of knee joint flexion were simulated without knee braces and knee braces of two different materials.The stress strains of the anterior cruciate ligament,posterior cruciate ligament,medial collateral ligament and lateral collateral ligament were analyzed under different loads.RESULTS AND CONCLUSION:(1)The peak stress of the four ligaments was changed at 0°,30°,and 60°angles,and after applying 320 N vertical compressive force and 134 N femur backward thrust,compared with bare knee,the peak stress of the anterior cruciate ligament was reduced at 0°and 30°,but the peak stress in the 60°flexion increased.The peak stress of the posterior cruciate ligament increased at 0°flexion and decreased in the 30°and 60°flexion.Peak stress of the medial collateral ligament and lateral collateral ligament was reduced at 0°,30°,and 60°angles.(2)Conclusion:Different materials of sports knee braces can protect the knee ligaments to a certain extent,but at specific angles will cause additional loads on the anterior cruciate ligament and posterior cruciate ligament,and the results of this study have the positive significance for the biomechanical research of knee ligaments,sports injury protection and the design and production of sports knee braces.