Biomechanical properties of knee articular cartilage

Issue title: Selected papers of the Euromech Colloquium No. 420, Mechanobiology of Cells and Tissues

Article type: Research Article

Authors: Laasanen, M.S.^; | Töyräs, J. | Korhonen, R.K.^; | Rieppo, J. | Saarakkala, S.^; | Nieminen, M.T. | Hirvonen, J. | Jurvelin, J.S.^;

Affiliations: Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio, Finland | Department of Anatomy, University of Kuopio, Kuopio, Finland

Note: [] Address for correspondence: J.S. Jurvelin, Ph.D., Dept. of Clinical Physiology and Nuclear Medicine, P.O. Box 1777, FIN‐70211 Kuopio, Finland. Tel.: +358 17 173 261; Fax: +358 17 173 244; E‐mail: [email protected].

Abstract: Structure and properties of knee articular cartilage are adapted to stresses exposed on it during physiological activities. In this study, we describe site‐ and depth‐dependence of the biomechanical properties of bovine knee articular cartilage. We also investigate the effects of tissue structure and composition on the biomechanical parameters as well as characterize experimentally and numerically the compression–tension nonlinearity of the cartilage matrix. In vitro mechano‐optical measurements of articular cartilage in unconfined compression geometry are conducted to obtain material parameters, such as thickness, Young's and aggregate modulus or Poisson's ratio of the tissue. The experimental results revealed significant site‐ and depth‐dependent variations in recorded parameters. After enzymatic modification of matrix collagen or proteoglycans our results show that collagen primarily controls the dynamic tissue response while proteoglycans affect more the static properties. Experimental measurements in compression and tension suggest a nonlinear compression–tension behavior of articular cartilage in the direction perpendicular to articular surface. Fibril reinforced poroelastic finite element model was used to capture the experimentally found compression–tension nonlinearity of articular cartilage.

Journal: Biorheology, vol. 40, no. 1-3, pp. 133-140, 2003