A processing method for kinematics data of human knee joint obtained by motion-capture measurement

Abstract

Background: The data obtained by motion capture method is many and complex, so it is the key to find an efficient method to process the data. Therefore，to develop a processing method for kinematics data of human knee joint by programming on MATLAB software. 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 processing. Results: Using the above methods, motion capture measurements and batch data processing were carried out on squatting and ascending stairs of 29 healthy volunteers to obtain the motion characteristics of the knee joint. As follows, the maximum range of internal and external rotation in squatting is 30.5 degrees, and the maximum range of internal and external rotation in climbing stairs is 16.5 degrees, etc., respectively compared with the results processed by other research methods, it is found that their movement results are basically consistent, thus verifying the reliability of our research method. Conclusion: The kinematics data of human knee joint could be processed accurately and effectively with the method by using MATLAB software, and the kinematics characteristics of human knee tibiofemoral joint were obtained. The processing method provides 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.