PARAMETRIC ANALYSIS USING THE FINITE-ELEMENT METHOD TO INVESTIGATE PROSTHETIC INTERFACE STRESSES FOR PERSONS WITH TRANS-TIBIAL AMPUTATION

A finite element (FE) model of the below-knee residual limb and prosth etic socket was created to investigate the effects of parameter variat ions on the interface stress distribution during static stance. This m odel was based upon geometric approximations of anthropometric residua l limb geometry. The model was not specific to an individual with ampu tation, but could be scaled to approximate the limb of a particular su bject. Parametric analyses were conducted to investigate the effects o f prosthetic socket design and residual limb geometry on the residual limb/prosthetic socket interface stresses. Behavioral trends were illu strated via sensitivity analysis, The results of the parametric analys es indicate that the residual limb/prosthetic socket interface stresse s are affected by variations in both prosthetic design and residual li mb geometry. Specifically, the analyses indicate: 1) the residual limb /prosthetic liner interface pressures are relatively insensitive to th e socket stiffness; 2) the stiffness of the prosthetic liner influence s the interface stress distribution for both the unrectified and patel lar-tendon-bearing (PTB) rectified models-the external load state appe ars to influence the interface pressure distribution, while the prosth etic socket rectification appears to influence the interface shear str ess distribution; 3) the interface pressures are very sensitive to the prosthetic rectification; 4) the shape and relative bulk of soft tiss ue may significantly influence the interface pressure distribution; 5) the interface pressure distribution is also influenced by the residua l limb length; and 6) the stiffness/compliance of the residual limb so ft tissues may significantly alter the interface pressure distribution .