Biomechanical behavior of plantar fat pad in healthy and degenerative foot conditions

The plantar fat pad of the human foot is a specific tissue made up of adipose chambers enveloped by fibrous septa. Aging, pathology or trauma may affect its histo-morphological configuration and mechanical response. The correlation between histo-morphological configuration and mechanical properties is analyzed by a computational approach, aiming to identify the influence of degenerative phenomena on plantar fat pad mechanics. Finite element meso-models, as numerical model of an intermediate-length scale, are developed for healthy and degenerative conditions, considering the different properties that degenerative phenomena may affect, such as the adipose chambers dimension, the fibrous septa thickness, the fibers orientation and the sub-components mechanical behavior. Histo-morphometric data are analyzed to identify average configurations of the fat chambers and fibrous septa, while specific constitutive formulations are provided to define their mechanical response. Numerical analyses are performed to identify the stress–strain behavior of the plantar fat pad considering healthy and degenerative configurations. The results from meso-models are applied to identify the parameters of a phenomenological constitutive formulation that interprets the overall human fat pad tissue mechanics. The constitutive formulation is implemented within a 3D finite element model of the heel region that is applied to evaluate the influence of degenerative phenomena on the overall mechanical functionality of the foot.

[1]  Cees W J Oomens,et al.  Linear viscoelastic behavior of subcutaneous adipose tissue. , 2008, Biorheology.

[2]  Ahmet Erdemir,et al.  An elaborate data set characterizing the mechanical response of the foot. , 2009, Journal of biomechanical engineering.

[3]  Kim Jk,et al.  The structural and functional organization of the connective tissue in the human foot with reference to the histomorphology of the elastic fibre system. , 1984, Acta morphologica Neerlando-Scandinavica.

[4]  J K Kimani,et al.  The structural and functional organization of the connective tissue in the human foot with reference to the histomorphology of the elastic fibre system. , 1984, Acta morphologica Neerlando-Scandinavica.

[5]  F. Tang,et al.  Comparison of the mechanical properties of the heel pad between young and elderly adults. , 1998, Archives of physical medicine and rehabilitation.

[6]  A. Mak,et al.  In vivo friction properties of human skin , 1999, Prosthetics and orthotics international.

[7]  Tijani Gharbi,et al.  Influence of the hydrophobic and hydrophilic characteristics of sliding and slider surfaces on friction coefficient: in vivo human skin friction comparison , 2004, Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging.

[8]  E Blechschmidt,et al.  The Structure of the Calcaneal Padding , 1982, Foot & ankle.

[9]  William R Ledoux,et al.  The shear mechanical properties of diabetic and non-diabetic plantar soft tissue. , 2012, Journal of biomechanics.

[10]  A. Gefen.  Plantar soft tissue loading under the medial metatarsals in the standing diabetic foot. , 2003, Medical engineering & physics.

[11]  Ahmet Erdemir,et al.  Reduction of plantar heel pressures: Insole design using finite element analysis. , 2006, Journal of biomechanics.

[12]  W D Pilkey,et al.  Linear and quasi-linear viscoelastic characterization of ankle ligaments. , 2000, Journal of biomechanical engineering.

[13]  C. G. Fontanella,et al.  Investigation on the load-displacement curves of a human healthy heel pad: In vivo compression data compared to numerical results. , 2012, Medical engineering & physics.

[14]  C. G. Fontanella,et al.  Biomechanical behaviour of heel pad tissue experimental testing, constitutive formulation, and numerical modelling , 2011, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[15]  Wen-Chung Tsai,et al.  Diabetic effects on microchambers and macrochambers tissue properties in human heel pads. , 2009, Clinical biomechanics.

[16]  C. G. Fontanella,et al.  A numerical model for investigating the mechanics of calcaneal fat pad region. , 2012, Journal of the mechanical behavior of biomedical materials.

[17]  A. Tietze,et al.  Concerning the Architectural Structure of the Connective Tissue in the Human Sole , 1982, Foot & ankle.

[18]  A. Gefen.  The biomechanics of heel ulcers. , 2010, Journal of tissue viability.

[19]  Piero G. Pavan,et al.  Investigation of foot plantar pressure: experimental and numerical analysis , 2010, Medical & Biological Engineering & Computing.

[20]  Pavana Abhiram Sirimamilla,et al.  Elaborate Experimentation for Mechanical Characterization of Human Foot Using Inverse Finite Element Analysis , 2009 .

[21]  M. Jahss,et al.  Investigations into the Fat Pads of the Sole of the Foot: Anatomy and Histology , 1992, Foot & ankle.

[22]  B L Davis,et al.  Characterization of the calcaneal fat pad in diabetic and non-diabetic patients using magnetic resonance imaging. , 1999, Magnetic resonance imaging.

[23]  A. W. Schopper,et al.  Analysis of effects of friction on the deformation behavior of soft tissues in unconfined compression tests. , 2004, Journal of biomechanics.

[24]  William R Ledoux,et al.  Histomorphological Evaluation of Diabetic and Non-Diabetic Plantar Soft Tissue , 2011, Foot & ankle international.

[25]  M. Jahss,et al.  Investigations into the Fat Pads of the Sole of the Foot: Heel Pressure Studies , 1992, Foot & ankle.

[26]  William R. Ledoux,et al.  The Quasi-Linear Viscoelastic Properties of Diabetic and Non-Diabetic Plantar Soft Tissue , 2011, Annals of Biomedical Engineering.

[27]  J. G. Kuhns,et al.  Changes in elastic adipose tissue. , 1949, The Journal of bone and joint surgery. American volume.

[28]  S. Prichasuk,et al.  The heel-pad compressibility. , 1994, Clinical orthopaedics and related research.

[29]  M Raspanti,et al.  Collagen structure and functional implications. , 2001, Micron.

[30]  Weiliam Chen,et al.  Cells and tissue interactions with glycated collagen and their relevance to delayed diabetic wound healing. , 2009, Biomaterials.

[31]  Jasper Tong,et al.  Technique to study the biomechanical properties of the human calcaneal heel pad , 2003 .

[32]  C. G. Fontanella,et al.  Investigation of the mechanical behaviour of the foot skin , 2014, Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging.

[33]  K. Rome.  Mechanical properties of the heel pad: current theory and review of the literature , 1998 .

[34]  C. G. Fontanella,et al.  Constitutive formulation and analysis of heel pad tissues mechanics. , 2010, Medical engineering & physics.

[35]  William R. Ledoux,et al.  The compressive mechanical properties of diabetic and non-diabetic plantar soft tissue. , 2010, Journal of biomechanics.

[36]  John L. Ricci,et al.  Histology and Histomorphometric Analysis of the Normal and Atrophic Heel Fat Pad , 1995, Foot & ankle international.

[37]  Norman A. Fleck,et al.  The compressive response of porcine adipose tissue from low to high strain rate , 2012 .

[38]  P.J. Hunter,et al.  Mechanics of the foot Part 1: A continuum framework for evaluating soft tissue stiffening in the pathologic foot , 2012, International journal for numerical methods in biomedical engineering.