Abstract
The viscous property of synovial fluids and sodium hyaluronate (HA) solutions with and without proteins was measured by a cone/plate viscometer. The influences of molecular weight and concentration of HA, solvents and addition of proteins on viscosity were examined. It was shown that at low shear rates, the higher the molecular weight and concentration of HA are, the higher the viscosity of HA solution is. It is noted that addition of albumin alone to HA solution decreases the viscosity, which is subsequently returned to the original level by the addition of γ-globulin. Next, the effect of lubricant viscosity on frictional behavior in natural synovial joints was investigated by pendulum tests of pig shoulder joints under both high- and low-load conditions, The dependence of friction on viscosity, which was changed by HA concentration or addition of proteins, was clearly demonstrated under the low-load condition.