Effects of a Single Intra-Articular Injection of 2% Lidocaine or 0.5% Bupivacaine on Synovial Fluid Acute Phase Protein Concentrations in Healthy Horses.

The research studied the impact of injecting different substances into the joints of healthy horses and found bupivacaine safer for intra-articular injection than lidocaine, with saline solution not recommended due to the inflammatory reaction it causes.

Objective and Methodology

• The research’s aim was to investigate whether 2% lidocaine, 0.5% bupivacaine, or 0.9% saline solution caused an inflammation response in horses’ middle carpal joints.
• Twenty horses participated in the study, with the right middle carpal joint of ten horses receiving 5 mL of 0.5% bupivacaine and the other ten receiving 5 mL of 2% lidocaine. The horses’ left middle carpal joints were treated with the control, 5 mL of 0.9% saline.
• Before and after each injection, serum and synovial fluid (SF) were collected in a sterile manner and analyzed for a range of protein and other concentrations. Each of these measures was compared across treatments using sodium dodecyl sulfate polyacrylamide gel electrophoresis.
• The results were statistically analyzed using SAS, with the Student-Newman-Keuls test comparing means. A significance level of 0.05 was used.

Results and Conclusions

• Both lidocaine and bupivacaine injections resulted in changes to serum and SF that suggested inflammation. However, lidocaine appeared to drive a more pronounced response.
• Interestingly, even the saline solution induced an inflammatory response. However, this was less intense than the response to lidocaine and bupivacaine.
• These findings suggested that bupivacaine is a safer option than lidocaine for intra-articular injection in horses. Saline solution, conversely, seems unsuitable due to the inflammation it causes.

Implications

• This research contributes to a better understanding of how different substances influence inflammation when injected into horse joints. It suggests safer alternatives for intra-articular injections, thus potentially improving medical procedures for horses.
• Further research may be required to validate these findings and to understand the long-term effects of these substances when injected into the horse’s joints.