title: The in vivo plantar soft tissue mechanical property under the metatarsal head: implications of tissues׳ joint-angle dependent response in foot finite element modeling.
abstract: Material properties of the plantar soft tissue have not been well quantified in vivo (i.e., from life subjects) nor for areas other than the heel pad. This study explored an in vivo investigation of the plantar soft tissue material behavior under the metatarsal head (MTH). We used a novel device collecting indentation data at controlled metatarsophalangeal joint angles. Combined with inverse analysis, tissues׳ joint-angle dependent material properties were identified. The results showed that the soft tissue under MTH exhibited joint-angle dependent material responses, and the computed parameters using the Ogden material model were 51.3% and 30.9% larger in the dorsiflexed than in the neutral positions, respectively. Using derived parameters in subject-specific foot finite element models revealed only those models that used tissues׳ joint-dependent responses could reproduce the known plantar pressure pattern under the MTH. It is suggested that, to further improve specificity of the personalized foot finite element models, quantitative mechanical properties of the tissue inclusive of the effects of metatarsophalangeal joint dorsiflexion are needed.
authors.affiliation: Department of Mechanical Engineering, Melbourne School of Engineering, University of Melbourne, Victoria, Australia. Electronic address: wenming.chen@unimelb.edu.au.
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, College of Biomedical Science & Engineering, Inje University, Gyongnam, Republic of Korea.
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Melbourne School of Engineering, University of Melbourne, Victoria, Australia. Electronic address: pvlee@unimelb.edu.au.
authors.forename: Peter Vee Sin
authors.initials: PVS
authors.lastname: Lee
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D003198:Computer Simulation; D020342:Finite Element Analysis; D005528:Foot / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000502:physiology; D008682:Metatarsal Bones / Q000502:physiology*; D008954:Models, Biological; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology*
keywords: Finite element model; Foot biomechanics; Mechanical properties; Metatarsal head; Plantar soft tissue