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Gunter Spahn, Enrico Kahl, Hans Michael Klinger, Thomas Mckley, Manfred Gnther, Gunther O. Hofmann
Mechanical behavior of intact and low-grade degenerated cartilage / Mechanische Eigenschaften von intaktem und niedriggradig geschdigtem Knorpel
Keywords: cartilage, failure, plasticity, Shore hardness, stiffness, E-Modul, Knorpel, Plastizitt, Shore-Hrte-Steifigkeit, Versagenslast
Young's modulus, elastic and plastic deformation, mechanical hardness and load at failure were determined for low-grade degenerated hyaline cartilage in a porcine model. Osteochondral plugs from the medial condyle of 30 female pigs were used. Cartilage defects were classified using the International Cartilage Repair Society (ICRS) protocol. Mechanical hardness was measured using a Shore A testing device. Total stiffness and plastic deformation was evaluated in the range 50200N using a 5-mm indenter. The load at failure was then determined. ICRS grade I specimens showed significantly lower stiffness than grade 0 specimens. ICRS grade 0 specimen showed no significant plastic deformation within the load range 25100N. In degenerated cartilage, plastic deformation started at a significantly lower load (50N). The Young's modulus at 25N in ICRS grade 0 specimens (18.8MPa) was significantly higher than in grade I (11.1MPa) or grade II (10.5MPa) specimens. Intact cartilage showed significantly higher tension at failure and mechanical Shore A hardness. Young's modulus and tension at failure showed strong correlation. Cartilage degeneration is associated with a significant loss of elasticity and mechanical stress resistance. Shore hardness measurement is an adequate method for rapid biomechanical evaluation of cartilage specimens.
Biomedizinische Technik, Walter de Gruyter
Print ISSN: 0013-5585
Volume: 52, 04/2007
Pages: 216 - 222