Combining gait analysis and finite element modeling to optimize offloading insoles for calcaneal ulcers

Calcaneal ulcers, a significant complication in diabetic patients, are primarily caused by sustained mechanical stress. Therefore, making effective offloading is crucial for healing and prevention. However, a comprehensive understanding of how different geometric offloading elements and their volumetric variations influence biomechanical efficacy remains limited. The aim of this study is to systematically investigate three distinct offloading insole geometries (cylindrical, spherical, conical), each across three volumetric variations (10 mm, 20 mm, and 30 mm diameters) to reveal the exact biomechanical efficacy. In this scope, patient specific dynamic gait analysis results were utilized to perform more accurate Finite Element Analysis (FEA). A single healthy researcher was used as a model for this feasibility assessment. Gait analysis showed that all geometries reduced overall peak plantar pressure compared to barefoot walking. Findings indicated that the conical geometry achieved the greatest pressure reduction (approximately 34.5% in both feet). However, FEA revealed that this configuration also introduced higher localized stress concentrations, particularly in larger diameters. The spherical geometry offered a balanced approach with adequate offloading and more favorable internal stress distribution. The cylindrical geometry exhibited the most consistent and lowest stress values across all sizes, with predictable scaling. The relationship between void volume and offloading effectiveness was found to be non-linear and highly geometry-dependent. The integration of gait analysis and FEA provides a robust framework for evaluating offloading insoles, offering insights into both immediate pressure reduction and long-term material performance. These findings deliver evidence-based guidelines for the rational design of patient-specific offloading interventions, contributing to improved wound healing and reduced recurrence in calcaneal ulcer management.