title: An alternative mechanical parameter for assessing the viability of articular cartilage.
abstract: This paper is a sequel to previously published findings showing that mechanical indentation alone cannot clearly discriminate between normal and degraded articular cartilage. Consequently, the structural elasticity potential Rc = epsilon r/sigma i, which combines indentation stress sigma i with near-instantaneous rebound epsilon r following unloading, is hypothesized as a potential cartilage assessment parameter, which arguably measures the integrity of the collagen fibre-proteoglycan entrapment system. To establish the validity of our hypothesis, samples of normal intact, artificially degraded, and osteoarthritic bovine cartilage were subjected to quasi-static compression at 0.1 s(-1) and 0.025 s(-1) to 30 per cent strain and then unloaded. A significant reduction in recovery was observed for artificially and naturally degraded samples in the first 5s following unloading (p < 0.01). The structural elasticity potential provided a considerable improvement over the results obtained using the individual indentation and rebound parameters to distinguish between paired normal and artificially degraded samples and indicated a high statistical significance of p < 0.005 when applied to the differentiation of normal and osteoarthritic samples.
authors.affiliation: Institute of Health and Biomechanical Innovation, Faculty of Built Environment and Engineering, Queensland University of Technology, 2 George St, Brisbane, 4000, Australia.
authors.forename: C P
authors.initials: CP
authors.lastname: Brown
authors.forename: R W
authors.initials: RW
authors.lastname: Crawford
authors.forename: A
authors.initials: A
authors.lastname: Oloyede
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000503:physiopathology*; D002417:Cattle; D003198:Computer Simulation; D055119:Elastic Modulus; D006244:Hardness; D006245:Hardness Tests / Q000379:methods*; D066298:In Vitro Techniques; D008297:Male; D008954:Models, Biological; D010003:Osteoarthritis / Q000503:physiopathology*; D014783:Viscosity