THE EFFECTS OF TEMPERATURE-CHANGES AND ARTHRITIS ON THE LUBRICATING PROPERTIES OF SYNOVIAL-FLUID

The aim of this study was to examine the effect of temperature on the rheological and lubricating properties of synovial fluid. The temperat ure dependence of the lubricant characteristics critical to the lubric ation processes operating in synovial joints, namely the viscosity and the pressure-viscosity coefficient, were evaluated experimentally in apparatus designed for this purpose. Viscosity was measured using a co ne on plate viscometer, while an optical interferometry elastohydrodyn amic test rig was used to evaluate the pressure-viscosity characterist ics of the fluid. The temperature in both cases was controlled by a he ating/cooling recirculating bath. The results of this study indicate t hat the non-Newtonian behaviour of synovial fluid is enhanced at tempe ratures lower than the normal joint operating temperature and that the viscosity of synovial fluid increases dramatically at the pressures g enerated in the contact. It has also been confirmed that the lubricati ng properties of synovial fluid are affected by joint disorder.