Development of stress measurement system during human stand-up motion using accurate shape knee joint model

Recently, the knee osteoarthritis (OA) patients are increasing, and their qualities of life would be worsen. In order to cope with this, clarifying the mechanism of the knee OA is important, so it is needed to inspect knee joints for understanding of the disease. In this study, the new experiment system was developed to measure knee femur-tibia joint contact pressure distribution during human stand-up motion using knee joint model. Accurate shape knee joint model was fabricated from high polymer material with the use of 3D printer based on human medical images. Knee joint kinematics and joint force during human stand-up motion were reproduced respectively by a robot manipulator and air cylinders. Pressure distribution of knee joint model was measured statically and dynamically, and it was found that medial pressure on the tibial plateau was higher than lateral one, which corresponds with the clinical observation. Therefore, the new proposed method is feasible to investigate knee joints.