Mechanical characterization and comparison of energy storage and return prostheses.

Area of Science:

• Biomechanics
• Biomedical Engineering
• Materials Science

Background:

• Standardized mechanical characterization of energy storage and return (ESAR) prostheses is crucial for performance evaluation.
• Current methods may be confounded by subject-specific gait variations.
• Finite Element Analysis (FEA) presents a potential solution for objective assessment.

Purpose of the Study:

• To investigate the suitability of FEA for standardizing the mechanical characterization of ESAR prostheses.
• To propose and validate a methodology combining experimental and numerical analysis for ESAR prostheses.
• To compare the mechanical properties and performance of different ESAR prosthetic models.

Main Methods:

• Gait analysis to determine optimal orientation angles for non-destructive testing (NDT).
• Quasi-static inverse FEA procedure in COMSOL Multiphysics® to determine homogenized material properties.
• Simulation of prostheses' loading response under bodyweight using Eigenfrequency and time-dependent analysis.

Main Results:

• Apparent stiffness values under bodyweight were determined for four different prostheses.
• Energy stored and returned varied inversely with stiffness across the tested prostheses.
• Overall prosthetic efficiency remained consistent, ranging from 51.7% to 52.7%.

Conclusions:

• The proposed FEA-based methodology enables standardized assessment and comparison of ESAR prostheses.
• This approach mitigates confounding factors related to individual gait characteristics.
• FEA provides a reliable tool for objective evaluation of prosthetic device mechanics.