Effects of anesthesia of the palmar digital nerves on kinematic gait analysis in horses with and without navicular disease.

The research study investigates the effects of local anesthesia administered to the palmar digital nerves of Quarter horses’ forelimbs, specifically looking at kinematic gait changes in horses with and without navicular disease.

Research Methods

• The study used a sample of 12 adult Quarter Horses, comprising 5 clinically normal (or sound) horses and 7 with diagnosed navicular disease.
• Kinematic measurements were taken as the horses trotted on a treadmill. These measurements were taken before and after a palmar digital nerve block (PDNB) was administered.
• To ensure the accuracy of the measurements, 23 different factors relating to displacement, joint angle, and temporal gait were measured for 5 strides in each horse. Among the measurements were elements related to the right forelimb and head.
• Prior to measurements involving the right forelimb, a PDNB was administered to the left forelimb.
• Comparisons were made between the kinematic measurements before and after the PDNB was applied to the right forelimb. These comparisons were statistically analyzed using a multiple ANOVA test, with an alpha level of 0.05. Further adjustments for posthoc comparisons were made using the Bonferroni correction.

Research Findings

• The study observed that in the healthy horses, the only significant kinematic change post-PDNB block was a decrease in the maximum extension of the metacarpophalangeal joint at mid-stance, by an approximate angle of 2 degrees.
• In horses diagnosed with navicular disease, several key changes were observed post-PDNB. There was a significant increase in the mean maximum extension of the metacarpophalangeal joint during the stance phase, as well as maximum flexion of the carpal joint during the swing phase.
• Other findings in horses with navicular syndrome included significantly shorter durations for the total stance phase, cranial stance phase, and break-over.
• Differences in minimum head heights during the stance phase for each forelimb and total vertical head excursion during a complete stride were also notably smaller after the PDNB was administered.

Conclusion

• The study concluded that several kinematic measurements of gait, collected while the horses were trotting on a treadmill, could be effectively utilized to determine if horses diagnosed with navicular disease experienced an improvement in lameness post-PDNB block.