Finite element analysis of the amputated lower limb: A systematic review and recommendations

Abstract

The care and rehabilitation of individuals after lower limb amputation presents a substantial and growing socioeconomic challenge. Clinical outcome is closely linked to successful functional rehabilitation with a prosthetic limb, which depends upon comfortable prosthetic limb - residual limb load transfer. Despite early interest in the 1980s, the amputated limb has received considerably less attention in computational biomechanical analysis than other subjects, such as arthroplasty. This systematic literature review investigates the state of the art in residual limb finite element analysis published since 2000. The identified studies were grouped into the following categories: (1) residuum-prosthesis interface mechanics; (2) residuum soft tissue internal mechanics; (3) identification of residuum tissue characteristics; (4) proposals for incorporating FEA into the prosthesis fitting process; (5) analysis of the influence of prosthetic componentry concepts to improve load transfer to the residuum, such as the monolimb and structural socket compliance; and (6) analysis of osseointegrated (OI) prostheses. The state of the art is critically appraised in order to form recommendations for future modeling studies in terms of geometry, material properties, boundary conditions, interface models, and relevant but un-investigated issues. Finally, the practical implementation of these approaches is discussed.

Considering passive mechanical properties and patient user motor performance in lower limb prosthesis design optimization to enhance rehabilitation outcomes

“…For example, footwear may substantially affect regional and overall stiffness and damping of prosthetic feet, in some instances normalizing the mechanical function across designs 35, 37, 39, 70 . Additionally, the choice of suspension system and constituent components 71 will play a role in determining the residuum-prosthesis interface properties and behavior 72, 73 , and this is especially relevant with the advent of bone-anchored prostheses (osseointegration) 74 . Therefore, a first application of the optimization process relates to evidence-based practice.…”

Influence of Gait Cycle Loads on Stress Distribution at The Residual Limb/Socket Interface of Transfemoral Amputees: A Finite Element Analysis

“…As reported in Dickinson et al 1 , there are not many studies using dynamic models with transfemoral amputees so the comparison with other authors is not extensive. However, the peak pressure values obtained in this study (ranging from 88 to 710 kPa) correspond in order of magnitude with those reported in Zhang et al 41 , who also added dynamics loads due to gait cycle (i.e., heel strike, midstance, terminal stance in their simulation).…”

“…Dynamic models that successfully include these compensated forces and moments could lead to more precise simulations. The aforementioned will not be evident in models that only take into account the static loads caused by the amputee's weight [19][20][21] which, to the best of the knowledge of the authors, are the only loads currently reported for transfemoral amputees 1 .…”

“…FEA has been used as an instrument for evaluating a wide range of aspects of lower limb amputees. FEA allows a less subjective analysis of factors that are difficult to study analytically or measure experimentally, including strains and stresses generated at the residual-limb/socket interface during the use of the prosthesis [1][2][3]10,14,[17][18][19] .…”

“…Although FEA on transfemoral amputees have been studied before, there is a need to evaluate the behaviour of the interface under dynamic loads. This will allow to analyse higher precision models for residual-limb load and boundary conditions that do not ignore changes in the coupling between the socket and the lower limb due to relative angular movements or axial displacements, or changes of variations in velocity and acceleration 1 . These dynamic conditions are present during the gait cycle, which is affected by the endogenous state of the amputee given that the asymmetry of the gait during ambulation radically differs from healthy gait parameters.…”