Finite element analysis for the estimation of the ground reaction force and pressure beneath the foot prosthesis during the gait of transfemoral patients

Ground reaction forces (GRF) and pressure beneath the foot prosthesis are the main parameters used in biomechanical analysis to estimate the joint load and evaluate the quality of the prosthesis, especially with transfemoral patient who have amputation that occurs through the femur. The information of ground reaction forces and beneath pressure of foot prosthesis is conventionally achieved using dynamics method or the experimental method. However, these methods have some limitation for a prosthetist and designers to choose the best prosthesis solution for transfemoral patient. In the dynamics method, the deformation of the foot prosthesis and the variation in the shape of the residual limb in the socket is neglected and the center of gravity of the prosthesis component is estimated; thus, the method is less accurate because the prosthesis consists of several parts with different materials and shapes. The experimental method involves time and cost in setting-up the device. Data can be acquired only after the patient wears the prosthesis. In this study, the authors were implemented a finite element (FE) method for computing the GRF, and the pressure beneath the foot prosthesis and its distribution. The finite element model of all components of transfemoral of the prosthesis was created. The ground reaction forces, beneath pressure of foot prosthesis and other parameters were disclosed after solving by explicit solver of LS-Dyna software. The results of the vertical ground reaction forces exhibit consistently similar data between the simulation and the measurement. A correlation coefficient of 0.91 between them denotes their correspondence. The reaction force at knee joint, distribution of beneath pressure of foot prosthesis were included in results and discussion. These results can be used for prosthesis design and optimization; they can assist the prosthetist in selecting a comfortable prosthesis for the patient and in improving the rehabilitation training.