title: A Model to Study Articular Cartilage Mechanical and Biological Responses to Sliding Loads.
abstract: In physiological conditions, joint function involves continuously moving contact areas over the tissue surface. Such moving contacts play an important role for the durability of the tissue. It is known that in pathological joints these motion paths and contact mechanics change. Nevertheless, limited information exists on the impact of such physiological and pathophysiological dynamic loads on cartilage mechanics and its subsequent biological response. We designed and validated a mechanical device capable of applying simultaneous compression and sliding forces onto cartilage explants to simulate moving joint contact. Tests with varying axial loads (1-4 kg) and sliding speeds (1-20 mm/s) were performed on mature viable bovine femoral condyles to investigate cartilage mechanobiological responses. High loads and slow sliding speeds resulted in highest cartilage deformations. Contact stress and effective cartilage moduli increased with increasing load and increasing speed. In a pilot study, changes in gene expression of extracellular matrix proteins were correlated with strain, contact stress and dynamic effective modulus. This study describes a mechanical test system to study the cartilage response to reciprocating sliding motion and will be helpful in identifying mechanical and biological mechanisms leading to the initiation and development of cartilage degeneration.
authors.affiliation: Laboratory for Soft Tissue Research, Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA. oliver.schaetti@zzm.uzh.ch.|Laboratory of Physiology and Biomechanics of the Masticatory System, Center for Oral Medicine, Dental and Maxillo-Facial Surgery, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland. oliver.schaetti@zzm.uzh.ch.|Institute for Biomechanics, Swiss Federal Institute of Technology, ETH Zentrum, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland. oliver.schaetti@zzm.uzh.ch.
authors.forename: Oliver R
authors.initials: OR
authors.lastname: Schätti
authors.affiliation: Laboratory of Physiology and Biomechanics of the Masticatory System, Center for Oral Medicine, Dental and Maxillo-Facial Surgery, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland.
authors.forename: Luigi M
authors.initials: LM
authors.lastname: Gallo
authors.affiliation: Laboratory for Soft Tissue Research, Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Torzilli
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D002417:Cattle; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D008954:Models, Biological; D013314:Stress, Mechanical; D016474:Weight-Bearing
chemical_list: D016326:Extracellular Matrix Proteins
keywords: Biotribology; Cartilage mechanics; Dynamic loading; Gene expression; Mechanobiology