Temperature effects in articular cartilage biomechanics

Abstract

SUMMARYArticular cartilage is the soft tissue that covers contacting surfaces of bones in synovial joints. Cartilage is composed of chondrocytes and an extracellular matrix containing numerous biopolymers, cations and water. Healthy cartilage functions biomechanically to provide smooth and stable joint movement. Degenerative joint diseases such as osteoarthritis involve cartilage deterioration, resulting in painful and cumbersome joint motion. Temperature is a fundamental quantity in mechanics, yet the effects of temperature on cartilage mechanical behavior are unknown. This study addressed the questions of whether cartilage stiffness and stress relaxation change with temperature. Samples of middle-zone bovine calf patellofemoral cartilage were tested in unconfined compression first at 24°C and then again after heating to 60°C. The data reveal that when temperature increases: (1) both peak and equilibrium stiffness increase by 150 and 8%, respectively, and (2) stress relaxation is faster at higher temperature, as shown by a 60% decrease in the time constant. The increases in temperature-dependent stiffness are consistent with polymeric mechanisms of matrix viscoelasticity but not with interstitial fluid flow. The changes in the time constant are consistent with a combination of both fluid flow and matrix viscoelasticity. Furthermore, we discovered a novel phenomenon: at stress-relaxation equilibrium, compressive stress increased with temperature. These data demonstrate a rich area of cartilage mechanics that has previously been unexplored and emphasize the role of polymer dynamics in cartilage viscoelasticity. Further studies of cartilage polymer dynamics may yield additional insight into mechanisms of cartilage material behavior that could improve treatments for cartilage degeneration. Supplementary material available online at

Mechanical and biochemical mapping of human auricular cartilage for reliable assessment of tissue-engineered constructs

“…Literature indicates no change in mechanical properties for articular cartilage between 20°C and 37°C (June and Fyhrie, 2010), and room temperature is routinely used (Mow et al, 1989).…”

An estimation of mechanical propertes of articular cartilage for biphasic finite element analyses

“…In the compressive experiment, the specimen was also kept in well water-soaked condition of PBS solution throughout the experiment to maintain hydration and osmotic phenomena. The compressive experiment and reservation state between experiments were executed in air-conditionated room temperature of 23°C, in which it was reported that articular cartilage drastically changes mechanical stiffness by exposing to around 60°C (June et al, 2010).…”

“…By advance of experimental apparatus, several experimental reports especially emphasized the importance of the high-speed compression, e.g. walking condition (June and Fyhrie, 2010;Espino et al, 2014). We should note that 3-dimensional FE model is also one of the physiological conditions.…”

Thermo-Mechanical Behaviour of Human Nasal Cartilage

“…Although water is the most abundant NC component, only a small portion is tightly bounded to the matrix. Thus, water within cartilaginous structures can be separated into fibrillar and intrafibrillar volumes [38]. Cartilage's affinity for water is primarily justified by the presence of significant quantities of PGs, whose negative side chain charges attract free positive ions and increase internal osmotic pressure [39,40].…”