Quantitative characterization of viscoelastic properties of synovial fluid from forelimb joints of orthopedically normal Thoroughbreds and warmblood horses.

The research article is an exploration of the viscoelastic properties of the synovial fluid in the joints of healthy athletic horses, specifically Thoroughbreds and Warmbloods, focusing on the differences within and between these two breeds.

Objective and Sample Group

• The study aimed to evaluate if there were differences in the viscoelastic properties of the synovial fluid drawn from different joints—metacarpophalangeal, intercarpal, and distal interphalangeal—of orthopedically normal athletic horses.
• The sample group consisted of 45 warmblood horses and 30 Thoroughbreds, all aged between 4 to 16 years.

Methods

• Synovial fluid samples were gathered aseptically via arthrocentesis from each horse’s specified joints, and the nucleated cell count was conducted.
• A commercial ELISA was employed to estimate the hyaluronic acid concentrations in the fluid samples.
• The full rheological characterization of the samples was carried out to assess the sample’s elastic or storage modulus (G’) and the viscous or loss modulus (G”) at 37.5°C, the horse’s body temperature.
• Comparisons of findings were made among the joints and between the breed groups using ANOVA

Results

• Significant distinctions were observed in synovial fluid G’ and G” values between Thoroughbreds and warmblood horses for the metacarpophalangeal joint.
• Additionally, it was found that there were significant differences within the breed groups, specifically between the metacarpophalangeal and intercarpal joints in Thoroughbreds, and between the metacarpophalangeal and distal interphalangeal joints and the intercarpal and distal interphalangeal joints in warmblood horses.
• However, no significant differences were discovered between the breed groups or across the joints in synovial fluid hyaluronic concentrations or nucleated cell counts.

Conclusion

• The study concluded that the viscoelastic properties of the forelimb joints in healthy Thoroughbreds and Warmblood horses differed within and across these two groups, mainly depending on the joint being examined.
• Significantly, this was reported to be a pioneering study of its kind, and the authors call for further research to develop a better understanding of the viscoelastic properties of synovial fluid in horses to improve their locomotive function.