Premium
Cartilage injury by ramp compression near the gel diffusion rate
Author(s) -
Morel Véronique,
Quinn Thomas M.
Publication year - 2004
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(03)00164-5
Subject(s) - strain rate , materials science , cartilage , stress relaxation , compression (physics) , chondrocyte , biomedical engineering , diffusion , matrix (chemical analysis) , composite material , anatomy , medicine , creep , physics , thermodynamics
The mechanics of cartilage injuries have implications for repair strategies. We examined the role of strain rate in cartilage injury under compression near the “gel diffusion” rate (the inherent tissue mechanical relaxation rate). Bovine osteochondral explant disks were subjected to one radially unconfined axial compression at approximately 0.1, 1, 10, 100, or 1000 times the gel diffusion rate to a peak stress of 3.5, 7, or 14 MPa. Effects were monitored in terms of axial strain, changes in water content, superficial cracks, chondrocyte viability, and proteoglycan release. Injury worsened monotonically with peak stress, but varied substantially with strain rate. High strain rates resulted in significant matrix fluid pressurization and impact‐like surface cracking with cell death near the superficial zone. Below the gel diffusion rate, cells died throughout the tissue depth during extensive matrix consolidation without cracks. At approximately the gel diffusion rate, no measurable injury occurred, even for peak stresses of 14 MPa and axial compressive strains near 0.8. The gel diffusion rate therefore represented a threshold separating different biomechanical regimes of injury, but at which cartilage was relatively “safe” from injury. Findings may help identify strategies for prevention and treatment of cartilage injury and suggest loading guidelines for tissue engineering. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.