Key considerations for finite element modelling of the residuum-prosthetic socket interface.

BACKGROUND

Finite element modelling has long been proposed to support prosthetic socket design. However, there is minimal detail in the literature to inform practice in developing and interpreting these complex, highly nonlinear models.

OBJECTIVES

To identify best practice recommendations for finite element modelling of lower limb prosthetics, considering key modelling approaches and inputs.

STUDY DESIGN

Computational modelling.

METHODS

This study developed a parametric finite element model using magnetic resonance imaging data from a person with transtibial amputation. Comparative analyses were performed considering socket loading methods, socket-residuum interface parameters and soft tissue material models from the literature, to quantify their effect on the residuum's biomechanical response to a range of parameterised socket designs.

RESULTS

These variables had a marked impact on the finite element model's predictions for limb-socket interface pressure and soft tissue shear distribution.

CONCLUSIONS

All modelling decisions should be justified biomechanically and clinically. In order to represent the prosthetic loading scenario in silico, researchers should (1) consider the effects of donning and interface friction to capture the generated soft tissue shear stresses, (2) use representative stiffness hyperelastic material models for soft tissues when using strain to predict injury and (3) interrogate models comparatively, against a clinically-used control.