Analysis of trans-femoral prosthetic gait based on the computational modelling and the principal component analysis of six-axis force/moment

Trans-femoral amputees are needed to regain moving pattern by refined rehabilitation program using load conditions on a prosthetic limb with the artificial knee joint. On the other hand, understanding loads applied on a prosthetic limb is important for biomechanical consideration of trans-femoral amputees. It is thought that inverse dynamics analysis is the most comprehensive method to obtain the joint reaction forces and the joint moments during gait for refining rehabilitation program of trans-femoral amputees. However, this method is highly constrained in respect to modeling of trans-femoral prosthesis and procedure of numerical computation. Alternatively, a multi-axis force/moment sensor can be used to directly measure loads applied on the middle part of trans-femoral prosthesis. In this paper, results of inverse dynamics analysis based on rigid link model and musculoskeletal model of human whole body by using motion capture system are compared with ones of direct measurement of lower thigh concerning trans-femoral prosthetic gait and comprehensive agreement is obtained. In addition, singular value decomposition extracted the pattern of operation with high correlation from joint force and joint moment also in the joint cooperation operation because quantitative evaluation technique of the various physical quantities during gait using principal component analysis has been proposed. Finally, the validity of inverse dynamics analysis and the effectiveness of the developed prosthetic gait training system to analyze comprehensive kinetic phenomena for trans-femoral prosthetic gait are validated. Especially, different specific loading pattern of downstairs walking will be useful to refine the rehabilitation protocol for trans-femoral amputees with a prosthetic limb.