title: Dynamic biomechanics correlate with histopathology in human tibial cartilage: a preliminary study.
abstract: Improved staging of cartilage degeneration is required, particularly during early stages when minimal surface damage is visible arthroscopically. Degradation of articular cartilage extracellular matrix, resulting from degenerative changes associated with osteoarthritis, can influence its functional properties. Cartilage mechanical properties therefore may provide a quantitative method for monitoring degenerative change in this tissue. We determined whether dynamic mechanical properties of cartilage (effective shear modulus and phase lag) measured with a handheld indenter correlated with histopathology scores, proteoglycan, and collagen content or expression of chondrocyte-specific (aggrecan, collagen II) or dedifferentiation (collagen I and III) genes in human osteoarthritic cartilage with International Cartilage Repair Society scores of 0 to 1. We observed an association between the histopathologic stage of cartilage disease and dynamic shear modulus and phase lag. In contrast, there generally was a poor relationship between cartilage biomechanical properties and biochemistry with the only noteworthy correlation being between shear modulus and collagen. Phase lag but not shear modulus correlated with gene expression. These data support the potential of dynamic indentation for assessing the stage of cartilage degeneration in tissue with minimal gross surface damage.
authors.affiliation: Raymond Purves Research Laboratory, Institute of Bone and Joint Research, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, Sydney, Australia.
authors.forename: Allan A
authors.initials: AA
authors.lastname: Young
authors.forename: Richard C
authors.initials: RC
authors.lastname: Appleyard
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Smith
authors.forename: James
authors.initials: J
authors.lastname: Melrose
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Little
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053674:Aggrecans / Q000235:genetics / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D024022:Fibrillar Collagens / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism; D033081:Shear Strength; D013977:Tibia / Q000473:pathology*
chemical_list: D053674:Aggrecans; D024022:Fibrillar Collagens; D011509:Proteoglycans; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases