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Anisotropic dynamic changes in the pore network structure, fluid diffusion and fluid flow in articular cartilage under compression

Greene, George W.; Zappone, Bruno; Söderman, Olle LU ; Topgaard, Daniel LU ; Rata, Gabriel LU ; Zeng, Hongbo and Israelachvili, Jacob N. (2010) In Biomaterials 31(12). p.3117-3128
Abstract
A compression cell designed to fit inside an NMR spectrometer was used to investigate the in situ mechanical strain response, structural changes to the internal pore structure, and the diffusion and flow of interstitial water in full-thickness cartilage samples as it was deforming dynamically under a constant compressive load (pressure). We distinguish between the hydrostatic pressure acting on the interstitial fluid and the pore pressure acting on the cartilage fibril network. Our results show that properties related to the pore matrix microstructure such as diffusion and hydraulic conductivity are strongly influenced by the hydrostatic pressure in the interstitial fluid of the dynamically deforming cartilage which differ significantly... (More)
A compression cell designed to fit inside an NMR spectrometer was used to investigate the in situ mechanical strain response, structural changes to the internal pore structure, and the diffusion and flow of interstitial water in full-thickness cartilage samples as it was deforming dynamically under a constant compressive load (pressure). We distinguish between the hydrostatic pressure acting on the interstitial fluid and the pore pressure acting on the cartilage fibril network. Our results show that properties related to the pore matrix microstructure such as diffusion and hydraulic conductivity are strongly influenced by the hydrostatic pressure in the interstitial fluid of the dynamically deforming cartilage which differ significantly from the properties measured under static i.e. equilibrium loading conditions (when the hydrostatic pressure has relaxed back to zero). The magnitude of the hydrostatic fluid pressure also appears to affect the way cartilage's pore matrix changes during deformation with implications for the diffusion and flow-driven fluid transport through the deforming pore matrix. We also show strong evidence for a highly anisotropic pore structure and deformational dynamics that allows cartilage to deform without significantly altering the axial porosity of the matrix even at very large strains. The insensitivity of the axial porosity to compressive strain may be playing a critical function in directing the flow of pressurized interstitial fluid in the compressed cartilage to the surface, to support the load, and provide a protective interfacial fluid film that 'weeps' out from the deforming tissue and thereby enhances the (elasto)hydrodynamic efficacy of sliding joints. Our results appear to show a close synergy between the structure of cartilage and both the hydrodynamic and boundary lubrication mechanisms. (C) 2010 Elsevier Ltd. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Porosity, Lubrication, Compression, Diffusion, Cartilage, Arthritis
in
Biomaterials
volume
31
issue
12
pages
3117 - 3128
publisher
Elsevier
external identifiers
  • wos:000276126000001
  • scopus:76749115119
ISSN
1878-5905
DOI
10.1016/j.biomaterials.2010.01.102
language
English
LU publication?
yes
id
dbbb075f-b179-4372-ae35-17e381b89937 (old id 1587150)
date added to LUP
2010-04-27 09:50:55
date last changed
2018-06-17 03:23:40
@article{dbbb075f-b179-4372-ae35-17e381b89937,
  abstract     = {A compression cell designed to fit inside an NMR spectrometer was used to investigate the in situ mechanical strain response, structural changes to the internal pore structure, and the diffusion and flow of interstitial water in full-thickness cartilage samples as it was deforming dynamically under a constant compressive load (pressure). We distinguish between the hydrostatic pressure acting on the interstitial fluid and the pore pressure acting on the cartilage fibril network. Our results show that properties related to the pore matrix microstructure such as diffusion and hydraulic conductivity are strongly influenced by the hydrostatic pressure in the interstitial fluid of the dynamically deforming cartilage which differ significantly from the properties measured under static i.e. equilibrium loading conditions (when the hydrostatic pressure has relaxed back to zero). The magnitude of the hydrostatic fluid pressure also appears to affect the way cartilage's pore matrix changes during deformation with implications for the diffusion and flow-driven fluid transport through the deforming pore matrix. We also show strong evidence for a highly anisotropic pore structure and deformational dynamics that allows cartilage to deform without significantly altering the axial porosity of the matrix even at very large strains. The insensitivity of the axial porosity to compressive strain may be playing a critical function in directing the flow of pressurized interstitial fluid in the compressed cartilage to the surface, to support the load, and provide a protective interfacial fluid film that 'weeps' out from the deforming tissue and thereby enhances the (elasto)hydrodynamic efficacy of sliding joints. Our results appear to show a close synergy between the structure of cartilage and both the hydrodynamic and boundary lubrication mechanisms. (C) 2010 Elsevier Ltd. All rights reserved.},
  author       = {Greene, George W. and Zappone, Bruno and Söderman, Olle and Topgaard, Daniel and Rata, Gabriel and Zeng, Hongbo and Israelachvili, Jacob N.},
  issn         = {1878-5905},
  keyword      = {Porosity,Lubrication,Compression,Diffusion,Cartilage,Arthritis},
  language     = {eng},
  number       = {12},
  pages        = {3117--3128},
  publisher    = {Elsevier},
  series       = {Biomaterials},
  title        = {Anisotropic dynamic changes in the pore network structure, fluid diffusion and fluid flow in articular cartilage under compression},
  url          = {http://dx.doi.org/10.1016/j.biomaterials.2010.01.102},
  volume       = {31},
  year         = {2010},
}