Experimental characterization of the mechanical properties of knee articular cartilages in compression: first approach with swine tissues

The knee articular cartilage must withstand large compressive loads, providing a soft and lubricated surface in the contact between bone epiphysis. This structure smoothies knee movements and promotes adequate load distribution. Assessing the mechanical properties of the articular cartilage and understanding its healthy behavior can be a way of preventing pathological situations like osteoarthritis. Animal models can be useful tools for the refining and previous deliberation of the best techniques for the study of human articular cartilage. The effectiveness of the information got from these studies depends on the resemblances and differences between animal and human articular cartilage biology, chemistry and mechanical properties. Bovine models has been used for the comparison of its articular cartilage mechanical properties, with the ones of humans. There are not many studies related to the mechanical properties of swine cartilage. The difficulty in testing in human samples and the similarities between these and the swine tissues justify this work. Hereupon, this work intends to characterize this biological structure by undergoing mechanical compression tests. Both unconfined and confined ramp-stress relaxation compression tests of cylindrical cartilage discs, extracted with a defined protocol from the swine femur, were utilized to determine Young’s modulus,E, and aggregate modulus, HA, of the cartilage tissue. The obtained results indicate values of E=0.3886 MPa and HA =0.4777 MPa. Correspondence to: Joana Catarina Ferreira Machado, INEGI Institute of Science and Innovation in Mechanical and Industrial Engineering Campus da FEUP, Rua Dr. Roberto Frias. 400 4200-465 Porto (Portugal), Tel: +351 225082151. E-mail: [email protected]