University of Michigan and Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, China.
Department of Human Anatomy, Histology and Embryology, Shanghai Jiao Tong University, Shanghai, China.
Biomech Model Mechanobiol. 2018 Oct;17(5):1373-1388. doi: 10.1007/s10237-018-1032-9. Epub 2018 May 24.
Recent research has shown that hyperelastic properties of the plantar soft tissue consisting of adipose tissue and fibrous septa change from region to region. However, relatively little research has been conducted to develop analytical or computational models to describe the region-specific behavior of the plantar soft tissue. The objective of the research is to develop a region-specific constitutive model of the plantar soft tissue. Plantar soft tissue specimens were dissected from six regions [subcalcaneal (CA), sublateral (LA), subnavicular (Nav), 1st, 3rd, and 5th submetatarsal (M1, M3, M5)] from cadaveric foot samples, and a picrosirius red staining technique was used to visualize the collagen fibers in fibrous septa. The volume fractions of adipose tissue and fibrous septa and the volume fractions of the principal orientations of the fibrous septa were calculated with the intensity gradient method. Region-specific constitutive models were then developed in finite element analysis considering the microstructure of the plantar soft tissue. The hyperelastic region specific material properties of the plantar soft tissue were validated with experimental unconfined compression tests and indentation tests from the literature. The results show that the models give reasonable predictions of the stiffness of the soft tissue within a standard deviation of the tests. The region-specific constitutive models help to explain how changes in the constituents are related to mechanical behavior of the soft tissue on a region specific basis.
最近的研究表明，由脂肪组织和纤维隔组成的足底软组织的超弹性特性在不同区域会发生变化。然而，目前相对较少的研究旨在开发分析或计算模型来描述足底软组织的特定区域行为。本研究的目的是开发一种足底软组织的特定区域本构模型。从尸体足部样本的六个区域（跟骨下（CA）、外侧下（LA）、舟骨下（Nav）、第一、第三和第五跖骨下（M1、M3、M5））解剖出足底软组织样本，并使用苦味酸天狼星红染色技术来观察纤维隔中的胶原纤维。使用强度梯度法计算脂肪组织和纤维隔的体积分数以及纤维隔的主方向的体积分数。然后，考虑足底软组织的微观结构，在有限元分析中开发特定区域的本构模型。使用文献中的无约束压缩试验和压痕试验验证了足底软组织的超弹性特定区域材料特性。结果表明，模型在试验标准偏差内给出了软组织刚度的合理预测。特定区域的本构模型有助于解释在特定区域基础上组成变化与软组织力学行为之间的关系。
