APPARENT VISCOSITY OF THE SYNOVIAL-FLUID FROM MID-CARPAL, TIBIOTARSAL, AND DISTAL INTERPHALANGEAL JOINTS OF HORSES

Objective-To compare the apparent viscosity of normal synovial fluid o f the mid-carpal, tibiotarsal, and interphalangeal joints of horses. D esign-Viscosity evaluation over a range of shear rates was used to cha racterize the apparent viscosity of synovial fluids from the 3 joints. Animals-60 clinically normal adult horses. Procedure-Viscosity data f or synovial fluid samples were obtained over a shear rate range of 10 to 250/s and apparent viscosity was calculated at 50, 100, 150, 200, a nd 250/s. Effect of shear rate on apparent viscosity was determined, u sing a two-way ANOVA, with significant differences tested, using a Tuk ey's test at a significance level of P < 0.05. Results-Synovial fluid from ail these joints indicated shear thinning behavior: decreased app arent viscosity with increased shear rate. Apparent viscosity of synov ial fluid from the 3 joints was not significantly different over the s hear rate range of 50 to 250/s. Conclusion-Results of this study indic ate that the apparent viscosity of the distal interphalangeal joint is not less than that of other joints, as has been reported. Clinical Re levance-The observation of decreased synovial fluid viscosity of dista l interphalangeal joint fluid should be considered as suggestive of jo int disease.