Custom orthotic design by integrating 3D scanning and subject-specific FE modelling workflow

Area of Science:

• Biomechanics
• Medical Engineering
• Computational Modeling

Background:

• Finite element (FE) foot models aid in understanding foot mechanics and designing custom orthoses.
• Current FE model development is often time-consuming and expensive.

Purpose of the Study:

• To develop a subject-specific scaled foot modeling workflow for orthotic design using scanned foot surface data.
• To validate the accuracy of the developed model in predicting interface pressures.

Main Methods:

• A subject-specific surface-based finite element model (SFEM) was created using scanned foot surfaces and scaled bone geometries.
• Geometric deviations between scaled and scanned surfaces were quantified.
• The SFEM was used to predict barefoot and foot-orthosis interface pressures.

Main Results:

• The average geometric deviation between scaled and scanned surfaces was 0.23 ± 0.09 mm, with no significant differences except in the lateral forefoot.
• The SFEM predicted foot-orthosis interface pressures with a maximum deviation of 7.1% compared to measurements.
• The model demonstrated good accuracy in predicting both barefoot and orthotic pressures.

Conclusions:

• The subject-specific scaled foot modeling workflow (SFEM) can accurately predict barefoot and foot-orthosis interface pressures.
• This SFEM technique has the potential to significantly expedite the design and optimization of custom foot orthoses.
• The developed workflow offers a more efficient alternative for creating patient-specific FE foot models.