A Data Process of Human Knee Joint Kinematics Obtained by Motion-Capture Measurement

Abstract

Background: The motion capture has been used as the usual method for measuring movement parameters of human, and most of the measuring data are obtained by partial manual process based on commercial software. A data process was developed for kinematics data obtain by programming on MATLAB software in this paper. Methods: The coordinate data of markers on human lower limb measured by motion capture system were firstly read and repaired through the program. Then the coordinate data of anatomical points in the movement of human lower limb were obtained by program processing. The local coordinate systems of human femur and tibia were established with anatomical points. After that the flexion/extension, abduction/adduction and internal/external rotation of human knee tibiofemoral joint in the movement of lower limb were obtained by coordinate transformation. Lastly, the motion capture and measurement of healthy volunteers were carried out and the MATLAB program was used for data process. Results: Using the above methods, motion capture measurements and batch data processing were carried out on squatting and climbing stairs of 29 healthy volunteers to obtain the motion characteristics of the knee joint. As followed, the maximum angle of internal and external rotation in squatting was 30.5 degrees, and the maximum angle of internal and external rotation in climbing stairs was 14 degrees, etc. The results of this paper also were respectively compared with the results processed by other research methods, and the results were basically consistent, thus the reliability of our research method was verified. Conclusion: The kinematics data of human knee joint could be processed accurately and effectively with the method programmed in MATLAB software, and the kinematics characteristics of human knee tibiofemoral joint were obtained. The processing method provided a reference for the designing and optimization of knee prosthesis, and the program can be modified for different purposes. At the same time, it is helpful to study knee joint movement of patients after total knee arthroplasty.