Finite Element Analysis Of Biomechanical Characteristics Of Tibio-Femoral Joint Under Knee Movement Of Flexion And Gait

The knee joint is the most complex joint in all human joints,and it is the most important physiological structure to maintain human movement.Because the motion of the knee joint is complex and the amount of exercise is large,the injury rate of the knee joint is much larger than other joints in the human body.Therefore,establishing a perfect three-dimensional finite element model of the knee joint can accurately understand the biomechanical properties and the injury mechanism of the knee joint.It is great significance for the prevention of knee joint diseases,injuries of sports and the design of individualized knee prosthesis.However,the dynamic simulation of knee joint movement is less researched.In this paper,the three-dimensional finite element model of natural knee joint and artificial knee joint were constructed by using the software of medical image processing Mimics and the software of finite element analysis Abaqus.The knee joint moment of flexion and gait are dynamically simulated by two finite element models.We studied and analyzed the biomechanical characteristics relative motion of tibio-femoral joint under flexion and gait motion.The specific work is as follows:(1)Based on the CT scan data of the volunteers' knee joint,a 3-D finite element model of complete natural knee joint(including patella,femur,tibia,articular cartilages,menisci,and major ligaments)was constructed by some software,such as,Mimics,HyperMesh and Abaqus.Based on the natural knee joint model,according to the requirements of the total knee replacement,the knee joint prosthesis were installed in the corresponding position of the knee joint and the 3-D finite element model of the artificial knee joint is established.It is proved to be valid by comparison with experiments and finite element models of other researchers.(2)The corresponding load was applied to the finite element model of the natural knee joint,and to simulate the knee joint movement of flexion 0°-60° and gait.The results show that:In the process of simulation natural knee flexion 0°-60°,The angle of internal rotation and valgus angle gradually increased with the increase of flexion angle.The femur has a significant posterior shift relative to tibia,and the shifted distance is from 4.36 mm to 7.23 mm,and the medial-lateral displacements are relatively stable.The contact stress of tibio-femoral cartilage and menisci gradually increased with the varied flexion angle,and the contact stress of medial meniscus is greater than that of lateral meniscus.In the process of simulation natural knee gait,the medial-lateral displacements and the varus-valgus angle of the tibial-femoral joint changed little.The femur has a posterior shift relative to tibia,and the shifted distance is from 0.58 mm to 5.54 mm,the range of internal-external rotation angle is-1.46° to 6.43°,and at the gait of about 90%,the internal rotation angle reach a maximum of 6.43°.At 13% gait,the contact stress of femoral cartilage,tibial cartilage and meniscus reached the maximum,mainly because the force of axial compression is greatest at 13% gait.(3)The corresponding load was applied to the finite element model of the artificial knee joint,and to simulate the knee joint movement of flexion 0°-60° and gait.The results show that:During simulation the artificial knee joint movement of flexion 0°-60° and gait,the relative motion and contact stress of the tibio-femoral joint is basically the same as that of the natural knee joint.However the tibio-femoral joint contact stress of the artificial knee joint is greater than that of the natural knee joint,but the relative motion range is slightly smaller than that of the natural knee joint.The results of this study can provide reference for the study of knee biomechanics,and provide guidance for designing individualized prosthesis and 3D printing of knee joints.