Associations between changes in loading pattern, deformity, and internal stresses at the foot with hammer toe during walking; a finite element approach. (August 2021)

• Record Type: Journal Article
• Authors: Moayedi, M.; Arshi, A.R.; Salehi, M.; Akrami, M.; Naemi, R.
• Is Part Of: Computers in biology and medicine. Volume 135(2021)
• Publication Date: 2021-08
• Subjects: Finite element analysis -- Plantar soft tissue -- Diabetic foot -- Foot ulcer -- Tissue biomechanics; Medicine -- Data processing -- Periodicals; Biology -- Data processing -- Periodicals; 610.285
• DOI: 10.1016/j.compbiomed.2021.104598
• Languages: English
• ISSNs: 0010-4825

Abstract

Abstract: Over the past decade, Finite Element (FE) modelling has been used as a method to understand the internal stresses within the diabetic foot. Foot deformities such as hammer toe have been associated with increased risk of foot ulcers in diabetic patients. Hence the aim of this study is to investigate the influence of hammer toe deformity on internal stresses during walking. A 3D finite element model of the human foot was constructed based on capturing Magnetic Resonance Imaging (MRI) of a diabetic neuropathic volunteer exhibiting hammer toe. 3D gait measurements and a multi-body musculoskeletal model for the same participant were used to define muscle forces. FE simulations were run at five different instances during the stance phase of gait. Peak plantar pressure and pressure distribution results calculated from the model showed a good agreement with the experimental measurement having less than 11% errors. Maximum von Mises internal stresses in the forefoot hard tissue were observed at the 3 rd and 5 th metatarsals and 4 th proximal phalanx. Moreover, presence of hammer toe deformity was found to shift the location of maximum internal stresses on the soft tissue to the forefoot by changing the location of centre of pressure with internal stress 1.64 times greater than plantar pressure. Hammer toe deformity also showed to reduce the involvement of the first phalanx in internal/external load-bearing during walking. The findings of this study support the association between changes in loading pattern, deformity, and internal stresses in the soft tissue that lead to foot ulceration. Highlights: We developed a 3D finite element modeling of the foot with hammer toe deformity. Gait analysis, musculoskeletal modelling, and electromyography test were utilised. Predicted internal stresses in the soft tissue were found to be 1.64 greater than plantar pressure. Maximum internal stresses in the hard tissue were observed at the 3 rd and 5 th metatarsals. Hammer toe shifts the location of maximum stresses to the forefoot and raises the risk of ulcers