title: A hyperelastic fibre-reinforced continuum model of healing tendons with distributed collagen fibre orientations.
abstract: The healing process of ruptured tendons is problematic due to scar tissue formation and deteriorated material properties, and in some cases, it may take nearly a year to complete. Mechanical loading has been shown to positively influence tendon healing; however, the mechanisms remain unclear. Computational mechanobiology methods employed extensively to model bone healing have achieved high fidelity. This study aimed to investigate whether an established hyperelastic fibre-reinforced continuum model introduced by Gasser, Ogden and Holzapfel (GOH) can be used to capture the mechanical behaviour of the Achilles tendon under loading during discrete timepoints of the healing process and to assess the model's sensitivity to its microstructural parameters. Curve fitting of the GOH model against experimental tensile testing data of rat Achilles tendons at four timepoints during the tendon repair was used and achieved excellent fits ([Formula: see text]). A parametric sensitivity study using a three-level central composite design, which is a fractional factorial design method, showed that the collagen-fibre-related parameters in the GOH model-[Formula: see text] and [Formula: see text]-had almost equal influence on the fitting. This study demonstrates that the GOH hyperelastic fibre-reinforced model is capable of describing the mechanical behaviour of healing tendons and that further experiments should focus on establishing the structural and material parameters of collagen fibres in the healing tissue.
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.|Faculty of Bioengineering and Medical Sciences, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.
authors.forename: M N
authors.initials: MN
authors.lastname: Bajuri
authors.affiliation: Department of Biomedical Engineering, Lund University, Lund, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Isaksson
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: Pernilla
authors.initials: P
authors.lastname: Eliasson
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK. mark.thompson@eng.ox.ac.uk.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Thompson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003094:Collagen / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D020342:Finite Element Analysis; D008954:Models, Biological; D051381:Rats; D013710:Tendons / Q000473:pathology*; D013718:Tensile Strength; D014945:Wound Healing
chemical_list: D003094:Collagen
keywords: Constitutive model; Fibre-reinforced material; Finite element analysis; Fractional factorial design; Tendon healing