Biomechanical Risk Factors of Diabetic Foot Ulceration: Engineering an insole design solution.

Abstract

Background: The global number of people with diabetes is estimated to reach 643 million by 2030 of whom 19-34% will present with diabetic foot ulceration. Insoles which offload high-risk ulcerative regions on the foot, by removing insole material, are the main treatment to reduce the likelihood of ulceration. However, their effect on the rest of the foot and relationship with gait kinematics has not been well researched. Additionally, passive offloading insoles cannot adapt to dynamic plantar loading and be optimised for the different regions of the foot. Aim: This project aims to research the biomechanical risk factors of diabetic foot ulceration and reduce the risk of diabetic foot ulceration for the people with diabetes by controlling biomechanical loading using passive and active insoles. Methods: Literature review giving background on diabetes, diabetic foot ulceration, and smart insoles intervention were conducted. A short study was conducted to investigate the safety of the passive offloading insole. Ten healthy subjects were recruited for the experiment to investigate the effect of passive offloading insoles on gait kinematics and plantar pressure. Another short study evaluated three concept designs for an active insole. An active insole was produced, and three participants were recruited for the evaluation of the active insole. Results: The average peak plantar pressure and pressure time integrals decreased by 30% and 36% at the region of interest when applying passive offloading insoles, whereas the heel strike and toe-off velocity increased by 15% and 12% whilst walking. The active insole demonstrated a reduction in average peak plantar pressure and pressure time integral by 35% and 31%, at the high-risk region of the metatarsal heads, whilst minimising edge effect and maintaining gait symmetry, regularity and cadence. Conclusion: Passive offloading insoles reduced plantar pressure at specific region but may increase pressure around these regions. Heel strike and toe-off velocities were increased under certain configurations of offloading insoles, potentially raising plantar pressure. The active insole demonstrated the feasibility of a system using predictive real time finite element driven soft hydraulic actuators to reduce plantar loading in diabetics.

Date of Award	31 Dec 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Glen Cooper (Supervisor) & Andrew Weightman (Supervisor)