Cartilage Interstitial Fluid Load Support in Unconfined Compression

2002 ◽  
Author(s):  
Seonghun Park ◽  
Ramaswamy Krishnan ◽  
Steven B. Nicoll ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Articular Surface ◽  
Surface Zone ◽  
Unconfined Compression ◽  
Tissue Samples ◽  
Fluid Load ◽  
Tension And Compression ◽  
Fluid Pressurization ◽  
Theoretical Analyses

Under physiological conditions of loading, articular cartilage is subjected to both compressive strains, normal to the articular surface, and tensile strains, tangential to the articular surface. Previous studies have shown that articular cartilage exhibits a much higher modulus in tension than compression. Theoretical analyses have suggested that this tension-compression nonlinearity enhances the magnitude of interstitial fluid pressurization during loading in unconfined compression, above a theoretical threshold of 33% of the average applied stress. The first hypothesis of this experimental study is that the peak fluid load support in unconfined compression is significantly greater than the 33% theoretical limit predicted for porous permeable tissues modeled with equal moduli in tension and compression [1]. The second hypothesis is that the peak fluid load support is higher at the articular surface side of the tissue samples than near the deep zone, because the disparity between the tensile and compressive moduli is greater at the surface zone.

scholarly journals Cartilage Interstitial Fluid Load Support in Unconfined Compression Following Enzymatic Digestion

2004 ◽  
Vol 126 (6) ◽  
pp. 779-786 ◽  
Author(s):  
Ines M. Basalo ◽  
Robert L. Mauck ◽  
Terri-Ann N. Kelly ◽  
Steven B. Nicoll ◽  
Faye H. Chen ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Enzymatic Digestion ◽  
Solid Matrix ◽  
Unconfined Compression ◽  
Support Mechanism ◽  
Before And After ◽  
Fluid Load ◽  
Wet Weight ◽  
Cartilage Biomechanics ◽  
Fluid Pressurization

Interstitial fluid pressurization plays an important role in cartilage biomechanics and is believed to be a primary mechanism of load support in synovial joints. The objective of this study was to investigate the effects of enzymatic degradation on the interstitial fluid load support mechanism of articular cartilage in unconfined compression. Thirty-seven immature bovine cartilage plugs were tested in unconfined compression before and after enzymatic digestion. The peak fluid load support decreased significantly p<0.0001 from 84±10% to 53±19% and from 80±10% to 46±21% after 18-hours digestion with 1.0 u/mg-wet-weight and 0.7 u/mg-wet-weight of collagenase, respectively. Treatment with 0.1 u/ml of chondroitinase ABC for 24 hours also significantly reduced the peak fluid load support from 83±12% to 48±16%p<0.0001. The drop in interstitial fluid load support following enzymatic treatment is believed to result from a decrease in the ratio of tensile to compressive moduli of the solid matrix.

scholarly journals Cartilage interstitial fluid load support in unconfined compression

2003 ◽  
Vol 36 (12) ◽  
pp. 1785-1796 ◽  
Author(s):  
Seonghun Park ◽  
Ramaswamy Krishnan ◽  
Steven B. Nicoll ◽  
Gerard A. Ateshian
Keyword(s):  
Interstitial Fluid ◽  
Unconfined Compression ◽  
Fluid Load

Permeability of Human Glenohumeral Joint Cartilage

1999 ◽  
Author(s):  
Anna Stankiewicz ◽  
Gerard A. Ateshian ◽  
Louis U. Bigliani ◽  
Van C. Mow
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Glenohumeral Joint ◽  
Solid Matrix ◽  
Joint Cartilage ◽  
Frictional Drag ◽  
Diarthrodial Joints ◽  
Flow Through ◽  
Fluid Pressurization

Abstract The nearly frictionless lubrication in diarthrodial joints and load support within articular cartilage depends on its mechanical properties. It has been shown that the majority of applied loads on cartilage are supported by interstitial fluid pressurization (Ateshian et al., 1994) which results from the frictional drag of flow through the porous permeable solid matrix. The duration and magnitude of this pressurization are a function of the permeability of cartilage (Lai et al., 1981).

Swelling and Curling Behaviors of Articular Cartilage

1998 ◽  
Vol 120 (3) ◽  
pp. 355-361 ◽  
Author(s):  
L. A. Setton ◽  
H. Tohyama ◽  
V. C. Mow
Keyword(s):  
Articular Cartilage ◽  
Residual Strain ◽  
Shape Change ◽  
Articular Surface ◽  
Ion Concentration ◽  
Ex Situ ◽  
Surface Zone ◽  
Sample Orientation ◽  
Residual Strains

A new experimental method was developed to quantify parameters of swelling-induced shape change in articular cartilage. Full-thickness strips of cartilage were studied in free-swelling tests and the swelling-induced stretch, curvature, and areal change were measured. In general, swelling-induced stretch and curvature were found to increase in cartilage with decreasing ion concentration, reflecting an increasing tendency to swell and “curl” at higher swelling pressures. An exception was observed at the articular surface, which was inextensible for all ionic conditions. The swelling-induced residual strain at physiological ionic conditions was estimated from the swelling-induced stretch and found to be tensile and from 3–15 percent. Parameters of swelling were found to vary with sample orientation, reflecting a role for matrix anisotropy in controlling the swelling-induced residual strains. In addition, the surface zone was found to be a structurally important element, which greatly limits swelling of the entire cartilage layer. The findings of this study provide the first quantitative measures of swelling-induced residual strain in cartilage ex situ, and may be readily adapted to studies of cartilage swelling in situ.

scholarly journals Modeling of Neutral Solute Transport in a Dynamically Loaded Porous Permeable Gel: Implications for Articular Cartilage Biosynthesis and Tissue Engineering

2003 ◽  
Vol 125 (5) ◽  
pp. 602-614 ◽  
Author(s):  
Robert L. Mauck ◽  
Clark T. Hung ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Solute Transport ◽  
Dynamic Loading ◽  
Interstitial Fluid ◽  
Articular Surface ◽  
Compressive Strain ◽  
Convective Transport ◽  
Solid Matrix ◽  
Bathing Solution ◽  
Loading Frequency

A primary mechanism of solute transport in articular cartilage is believed to occur through passive diffusion across the articular surface, but cyclical loading has been shown experimentally to enhance the transport of large solutes. The objective of this study is to examine the effect of dynamic loading within a theoretical context, and to investigate the circumstances under which convective transport induced by dynamic loading might supplement diffusive transport. The theory of incompressible mixtures was used to model the tissue (gel) as a mixture of a gel solid matrix (extracellular matrix/scaffold), and two fluid phases (interstitial fluid solvent and neutral solute), to solve the problem of solute transport through the lateral surface of a cylindrical sample loaded dynamically in unconfined compression with frictionless impermeable platens in a bathing solution containing an excess of solute. The resulting equations are governed by nondimensional parameters, the most significant of which are the ratio of the diffusive velocity of the interstitial fluid in the gel to the solute diffusivity in the gel Rg, the ratio of actual to ideal solute diffusive velocities inside the gel Rd, the ratio of loading frequency to the characteristic frequency of the gel f^, and the compressive strain amplitude ε0. Results show that when Rg>1,Rd<1, and f^>1, dynamic loading can significantly enhance solute transport into the gel, and that this effect is enhanced as ε0 increases. Based on representative material properties of cartilage and agarose gels, and diffusivities of various solutes in these gels, it is found that the ranges Rg>1,Rd<1 correspond to large solutes, whereas f^>1 is in the range of physiological loading frequencies. These theoretical predictions are thus in agreement with the limited experimental data available in the literature. The results of this study apply to any porous hydrated tissue or material, and it is therefore plausible to hypothesize that dynamic loading may serve to enhance solute transport in a variety of physiological processes.

Strain Dependent Variations in the Frictional Properties of Bovine Articular Cartilage

2004 ◽  
Author(s):  
Ramaswamy Krishnan ◽  
Monika Kopacz ◽  
Michael J. Carter ◽  
Gerard A. Ateshian
Keyword(s):  
Friction Coefficient ◽  
Interstitial Fluid ◽  
Compressive Strain ◽  
Compression Stress ◽  
Unconfined Compression ◽  
Temporal Response ◽  
Bovine Articular Cartilage ◽  
Frictional Properties ◽  
Fluid Load ◽  
Strain Dependent

This study investigates the hypothesis that the equilibrium friction coefficient of cartilage decreases with increasing compressive strain. Furthermore, when accounting for this strain-dependence, it is hypothesized that the temporal response of the friction coefficient correlates linearly with interstitial fluid load support, in the configuration of unconfined compression stress-relaxation. Both hypotheses were confirmed from theory and experiment.

Is Articular Cartilage Orthotropic in Compression?

1999 ◽  
Author(s):  
Michael A. Soltz ◽  
Robert L. Mauck ◽  
Clark T. Hung ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Compressive Modulus ◽  
The Other ◽  
Material Symmetry ◽  
Tension And Compression ◽  
Preliminary Study ◽  
Line Direction

Abstract Many studies have demonstrated that articular cartilage is anisotropic in tension, based on tensile tests of tissue strips harvested parallel to the articular surface, along and perpendicular to the local split line direction (e.g., Akizuki et al., 1986; Kempson et al., 1968; Schmidt et al., 1990; Woo et al., 1979). The observed differences in the tensile modulus suggest that the material symmetry of cartilage in tension is no higher than orthotropy, since two orthogonal planes of symmetry (with unit normals parallel and perpendicular to the split line direction) automatically define a third plane of symmetry mutually perpendicular to the other two. However, the properties of articular cartilage differ significantly in tension and compression (Cohen et al., 1998; Soulhat et al., 1998) and it remains to be established whether cartilage is anisotropic in compression as well. Only one previous preliminary study has investigated the compressive modulus of cartilage along two mutually perpendicular directions (Jurvelin et al., 1996), reporting significant differences.

Direct Hydraulic Permeability Measurements of Agarose Hydrogels Used as Cell Scaffolds

1999 ◽  
Author(s):  
Michael A. Soltz ◽  
Anna Stankiewicz ◽  
Gerard Ateshian ◽  
Robert L. Mauck ◽  
Clark T. Hung
Keyword(s):  
Fluid Flow ◽  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Convective Transport ◽  
Hydraulic Permeability ◽  
Interstitial Fluid Flow ◽  
Pass Through ◽  
Fluid Pressurization ◽  
First Time

Abstract The objective of this study was to determine the intrinsic hydraulic permeability of 2% agarose hydrogels. Two-percent agarose was chosen because it is a concentration typically used for encapsulation of chondrocytes in suspension cultures [3–5], Hydraulic permeability is a measure of the relative ease by which fluid can pass through a material. Importantly, it governs the level of interstitial fluid flow as well as the interstitial fluid pressurization that is generated in a material during loading. Fluid pressurization is the source of the unique load-bearing and lubrication properties of articular cartilage [1,17] and represents a major component of the in vivo chondrocyte environment. We have previously reported that 2% agarose hydrogels can support fluid pressurization, albeit to a significantly lesser degree than articular cartilage [18]. Interstitial fluid flow gives rise to convective transport of nutrients and ions [6,7] and matrix compaction [9] which may serve as important stimuli to chondrocytes. We report for the first time the strain-dependent hydraulic permeability of 2% agarose hydrogels.

Fibre Reinforcement and Mechanical Stability in Articular Cartilage

1984 ◽  
Vol 13 (3) ◽  
pp. 153-156 ◽  
Author(s):  
D W L Hukins ◽  
R M Aspden ◽  
Y E Yarker
Keyword(s):  
Articular Cartilage ◽  
Tensile Stress ◽  
Articular Surface ◽  
Applied Pressure ◽  
Swelling Pressure ◽  
Collagen Fibrils ◽  
Torsional Stiffness ◽  
Surface Zone ◽  
Fibre Reinforcement ◽  
Deep Zone

The gel phase of articular cartilage is reinforced by collagen fibrils. These fibrils have low flexural and torsional stiffness, but are able to provide reinforcement if deformation of the tissue increases their tensile stress. An estimate suggests that the lengths of collagen fibrils in articular cartilage are at least of the same order as their critical length so that tensile stress in the tissue will increase the stress in the fibrils rather than simply pull them out of the gel. In the surface zone the collagen fibrils are oriented so that the efficiency of reinforcement, η, is about 0.6 tangential to the surface; tension in the fibrils is thus able to withstand swelling pressure within the tissue whose condition for stability resembles that of a pressure vessel. Swelling pressure allows the tissue to support applied pressure. An intermediate zone has a roughly isotropic η value of about 0.2, while in the deep zone collagen fibrils appear to tie the cartilage to the subchondral bone; in this deep zone η has a value of about 0.6 perpendicular to the surface direction. There is also some preferred orientation of collagen fibrils in the plane of the articular surface within the surface zone; in patellar cartilage the preferred orientations can be related to the direction of stress which could be generated by movement of the joint.

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