Biomechanical design framework for prosthetic feet: Experimentally validated non-linear finite element procedure

Area of Science:

• Biomechanics
• Biomedical Engineering
• Computational Mechanics

Background:

• Prosthetic foot design traditionally relies on time-consuming and costly experimental evaluations.
• A need exists for efficient methods to predict biomechanical performance during the design phase.

Purpose of the Study:

• To present a numerical procedure for the a priori determination of prosthetic foot biomechanical parameters.
• To aid in the design and analysis of prosthetic feet.

Main Methods:

• Utilized finite element analysis (FEA) incorporating geometric, material, and contact non-linearity.
• Employed boundary conditions simulating the rocker-based inverted pendulum model.
• Validated the FEA model using an inverted pendulum apparatus with a Solid Ankle Cushioned Heel (SACH) prosthetic foot.

Main Results:

• The numerical procedure accurately determined key biomechanical parameters like roll-over characteristics and center of pressure trajectory.
• Validation against experimental data showed minimal errors, e.g., ~0.1% error in the radius of curvature of the roll-over shape.
• Results demonstrated clinical insignificance of discrepancies, confirming model reliability.

Conclusions:

• The proposed finite element analysis model provides reliable a priori insights into prosthetic foot biomechanics.
• This numerical approach can significantly inform the design, analysis, and prescription of prosthetic feet.
• Facilitates a more efficient and cost-effective design process for prosthetic devices.