Mechanical characteristics of diabetic and non-diabetic plantar skin

Crossland, Sarah R.; Sairally, Francesca; Edwards, Jen; Culmer, Peter; Brockett, Claire L.

Abstract

Diabetic foot ulceration is linked to high amputation and mortality rates, with the substantial associated annual spend on the at-risk diabetic foot reflecting the intensive time and labour involved in treatment. Assessing plantar interactions and developing improved understanding of the formation pathways of diabetic ulceration is important to orthotic interventions and patient outcomes. Plantar skin surrogates which emulate the mechanical and tribological characteristics can help improve physical models of ulceration, reduce reliance on cadaveric use and inform more complex computational modelling approaches. The information available from existing studies to characterise plantar skin is limited, typically featuring ex-vivo representations of skin and subcutaneous tissue combined and given focus to shear studies with time dependency. The aim of this study is to improve understanding of plantar tissue mechanics by assessing the mechanical characteristics of plantar skin in two groups; (1) non-diabetic and (2) diabetic donors without the subcutaneous tissue attachment of previous work in this field. Digital image correlation was used to assess inherent skin pre-tension of the plantar rearfoot prior to dissection. Young's modulus, storage and loss moduli were tested for using tensile stress-strain failure analysis and tensile and compressive dynamic mechanical analysis, which was conducted on excised plantar rearfoot donor specimens for both disease state cohorts at frequencies reflecting those achieved in activities of daily living. Plantar skin thickness for donor specimens were comparable to values obtained using ultrasound acquired in vivo values. Median tensile storage and loss moduli, along with Young's modulus, was higher in the diabetic cohort. With a mean Young's modulus of 0.83 ± 0.49 MPa and 1.33 ± 0.43 MPa for non-diabetic and diabetic specimens respectively. Compressive studies showed consistency between cohorts for median storage and loss moduli. The outcomes from this study show mechanical characteristics of plantar skin without the involvement of subcuteanous tissues under reflective daily achieved loading regimes, showing differences in the non-diabetic and diabetic specimens trialled to support improved understanding of plantar tissue response under tribological interactions.

Citation

Crossland, S. R., Sairally, F., Edwards, J., Culmer, P., & Brockett, C. L. (2024). Mechanical characteristics of diabetic and non-diabetic plantar skin. Journal of the mechanical behavior of biomedical materials, 150, Article 106279. https://doi.org/10.1016/j.jmbbm.2023.106279

• Journal Article Type: Article
• Acceptance Date: Nov 23, 2023
• Online Publication Date: Nov 24, 2023
• Publication Date: 2024-02
• Deposit Date: Nov 27, 2023
• Publicly Available Date: Nov 27, 2023
• Journal: Journal of the mechanical behavior of biomedical materials
• Print ISSN: 1751-6161
• Electronic ISSN: 1878-0180
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 150
• Article Number: 106279
• DOI: https://doi.org/10.1016/j.jmbbm.2023.106279
• Keywords: Diabetes; Plantar; Skin; Strain
• Public URL: https://hull-repository.worktribe.com/output/4458352
• Additional Information: This article is maintained by: Elsevier; Article Title: Mechanical characteristics of diabetic and non-diabetic plantar skin; Journal Title: Journal of the Mechanical Behavior of Biomedical Materials; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.jmbbm.2023.106279; Content Type: article; Copyright: © 2023 The Authors. Published by Elsevier Ltd.