Numerical Simulation And Experimental Research Of The Mechanical Behavior Of Total Knee Joint

Knee joint locates between hip joint and ankle joint of human body, which is the main joint of lower limbs movement. Morbidity of knee joint is increasing with age. Nowadays,osteoarthrosis shows a trend of younger age, which may trouble more people. It not only affects people’s movement and living quality, but also threats lives of aged patients to some extent. There are significant meanings of investigating mechanical properties of knee joint for preventing and treating arthropathy and sports injury.Based on CT scanning data with 3D reconstruction software Mimics, reverse engineering software Geomagic Studio and finite element software ABAQUS, this paper reconstructs 3D finite element model of total knee joint including total tibia, femur, patella,fibula, meniscus, articular cartilage and main articular ligament. Mechanical properties of knee joint and various bending angles affecting mechanical behavior of knee joint under physiological load were calculated and analyzed according to the model constructed. It’s found that the load of inner side cartilage and medial meniscus are larger than those of outer side. The load of inner edge of meniscus is larger than that of outer edge, and inner edge tends to be worn. Wearing and deficiency of meniscus will lead to the maldistribution of stress within knee joint, which causes deterioration of disease. The stresses of articular cartilage and meniscus increase with load. In the bending proceeding from 0° to 90° of the knee joint, the stresses of cartilages and meniscus are increasing with bending angle. The stress is smallest when the angle is 0° while it is largest when the angle is 90°. From 0° to 40°, the largest stresses of cartilages and meniscus all appear on the inner side, while from 40° to 90°, the largest stresses of cartilages and meniscus move to the outer side gradually. In the whole bending proceeding, the stress order from large to small is meniscus, tibia cartilage and femur cartilage. It is also found that the results by the model considering ligament agree with the animated knee since the model considering ligament guarantees the degree of freedom in coronal plane, vertical plane and transverse section.In order to verify the results of numerical calculation, the author manufactured an artificial femur, tibia, fibula and patellar combination model, set up a corresponding finite element model and analyzed strain distribution of the joint through compression loading method. The experiment scheme was designed according to the results of numerical simulation and the strain laws were acquired by electrical measuring method. By contrasting between experiment and numerical simulation explains knee strain change laws under compression load and proves the validity of the numerical simulation and the applicability. At the same time, it confirms feasibility of the knee joint construction method proposed in this paper. Knee joint mechanical behaviors are studied by numerical simulation and experiment in this paper, which is significant to improving the consciousness of the people to protect theknee joint, reducing joint damages and designing and optimizing biological equipment and prosthesis.