Cartilage disease is a significant health issue that affects millions of patients of all ages, yet there are few interventions to prevent or slow the disease. As mechanical wear is an important component of cartilage disease, the primary objective of this project was to investigate the wear characteristics of articular cartilage and factors that may improve the tissue’s wear resistance.
In developing test parameters for cartilage wear, two different cartilage surface geometries were compared: smaller flat specimen and larger curved specimens that made contact in the center but not at the edge. The cartilage wear of the two geometries was compared using three different techniques. A modified wear factor was considered to be the most accurate assessment of cartilage wear, but surface damage measurement with india ink was an effective, inexpensive and quick technique to evaluate potential implant materials. Finite element models showed that flat specimens showed excessive wear at the edges due to a non-physiologic stress concentration, while the larger specimens wore more uniformly across the surface.
To identify mechanical changes due to cartilage treatments, a semiautomated indentation protocol for repeatable material characterization of the tissue was developed. The technique incorporated a small preload to detect the tissue surface, followed by a stress relaxation test at a defined indentation depth.
The effect of artificially crosslinking collagen with genipin, a naturally occurring crosslinking agent, on the modulus, coefficient of friction and wear factor of cartilage was quantified. It was found that the concentration and the duration of exposure to genipin could both be varied to alter the cartilage modulus. Artificially crosslinking bovine cartilage in genipin solutions decreased the wear factor in a dose dependent manner. Crosslinking in 2 and 10 mM genipin for 15 minutes increased the stiffness by 16 and 62% and decreased the wear factor by 43 and 71%, respectively.
Finally, it was found that a single traumatic impact decreased the elastic modulus of cartilage by 23%. Immunohistochemistry demonstrated that this may be due to damage in the collagen matrix. Crosslinking the impacted cartilage reversed the loss of the modulus and left the tissue 37% stiffer than initially.
|1982||Armstrong CG, Mow VC. Variations in the intrinsic mechanical properties of human articular cartilage with age, degeneration, and water content. J Bone Joint Surg. 1982;64A(1):88-94.|
|1987||Mak AF, Lai WM, Mow VC. Biphasic indentation of articular cartilage, I: theoretical analysis. J Biomech. 1987;20(7):703-714.|
|1992||Mow VC, Ratcliffe A, Robin Poole A. Cartilage and diarthrodial joints as paradigms for hierarchical materials and structures. Biomaterials. 1992;13(22):67-97.|
|1991||Thompson RC Jr, Oegema TR Jr, Lewis JL, Wallace L. Osteoarthrotic changes after acute transarticular load: an animal model. J Bone Joint Surg. August 1991;73A(7):990-1001.|
|1998||Soltz MA, Ateshian GA. Experimental verification and theoretical prediction of cartilage interstitial fluid pressurization at an impermeable contact interface in confined compression. J Biomech. October 1998;31(10):927-934.|
|2001||Kurz B, Jin M, Patwari P, Cheng DM, Lark MW, Grodzinsky AJ. Biosynthetic response and mechanical properties of articular cartilage after injurious compression. J Orthop Res. 2001;19(6):1140-1146.|
|1994||Setton LA, Mow VC, Müller FJ, Pita JC, Howell DS. Mechanical properties of canine articular cartilage are significantly altered following transection of the anterior cruciate ligament. J Orthop Res. July 1994;12(4):451-463.|
|1971||Mankin HJ, Dorfman H, Lippiello L, Zarins A. Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips, II: correlation of morphology with biochemical and metabolic data. J Bone Joint Surg. April 1971;51A(3):523-537.|
|1998||Bank RA, Bayliss MT, Lafeber FPJG, Maroudas A, Tekoppele JM. Ageing and zonal variation in post-translational modification of collagen in normal human articular cartilage: the age-related increase in non-enzymatic glycation affects biomechanical properties of cartilage. Biochem J. February 15, 1998;3301(1):345-351.|
|1984||Armstrong CG, Lai WM, Mow VC. An analysis of the unconfined compression of articular cartilage. J Biomech Eng. May 1984;106(2):165-173.|
|2005||Wilson W, van Donkelaar CC, van Rietbergen B, Huiskes R. A fibril-reinforced poroviscoelastic swelling model for articular cartilage. J Biomech. June 2005;38(6):1195-1204.|
|1971||Kempson GE, Freeman MAR, Swanson SAV. The determination of a creep modulus for articular cartilage from indentation tests on the human femoral head. J Biomech. July 1971;4(4):239-250.|
|1984||Eyre DR, Paz MA, Gallop PM. Cross-linking in collagen and elastin. Ann Rev Biochem. 1984;53:717-748.|
|1989||Mow VC, Gibbs MC, Lai WM, Zhu WB, Athanasiou KA. Biphasic indentation of articular cartilage, II: a numerical algorithm and an experimental study. J Biomech. 1989;22:853-861.|
|1999||Hunziker EB. Articular cartilage repair: are the intrinsic biological constraints undermining this process insuperable? Osteoarthritis Cartilage. January 1999;7(1):15-28.|
|1992||Oliver WC, Pharr GM. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J Mater Res. 1992;7(6):1564-1583.|
|1980||Mow VC, Kuei SC, Lai WM, Armstrong CG. Biphasic creep and stress relaxation of articular cartilage in compression: theory and experiments. J Biomech Eng. February 1980;102(1):73-84.|
|1990||Fithian DC, Kelly MA, Mow VC. Material properties and structure-function relationships in the menisci. Clin Orthop Relat Res. March 1990;252:19-31.|
|1976||Hori RY, Mockros LF. Indentation tests of human articular cartilage. J Biomech. 1976;9(4):259-268.|
|2008||Oyen ML, Ferguson VL, Bembey AK, Bushby AJ, Boyde A. Composite bounds on the elastic modulus of bone. J Biomech. August 7, 2008;41(11):2585-2588.|
|1978||Hayes WC, Bodine AJ. Flow-independent viscoelastic properties of articular cartilage matrix. J Biomech. 1978;11(8-9):407-419.|
|1962||McCutchen CW. The frictional properties of animal joints. Wear. January–February 1962;5(1):1-17.|
|1973||Radin EL, Parker HG, Pugh JW, Steinberg RS, Paul IL, Rose RM. Response of joints to impact loading, III: relationship between trabecular microfractures and cartilage degeneration. J Biomech. January 1973;6(1):51-57.|