Evaluation of the effects of geometrical changes in prosthetic socket towards transfemoral residuum via finite element method

This study investigated the effect of prosthetic socket shape on the transfemoral residuum by using the finite element method. The effect of two Ischial-ramal-containment sockets (MCCT and UCLA) was evaluated during the donning process by predicting the qualitative measurement in a simulation. The simulation, mimicking the actual donning process, was done by creating a finite element model of residuum and socket based on the MRI image of subject`s residuum with and without socket. The change of contact surface pressure and geometry of the residuum were observed in the cross-section area along 170 mm from the distal end. A high correlation coefficient of pressure was recorded between experiment and simulation (0.976) with a mean error of 4.93% in UCLA case. The simulation results also showed that the maximum pressure of residuum in MCCT socket was higher than that in UCLA. The highest changes of soft tissue area occurred at the edge of both sockets—6.03% and 6.06% of increment for MCCT and UCLA respectively. The existence of pressure at the measuring point changed the residuum geometry, increasing 11.32% and 7.24% residuum length for UCLA and MCCT respectively. Our result will help the engineer and prosthetist to understand the residuum behavior during donning process. Moreover, it may help in modifying the socket shape to offer better comfort to the subject.