The effects of local anaesthetic solution in the navicular bursa of horses with lameness caused by distal interphalangeal joint pain.

This research involves a study on horses diagnosed with distal interphalangeal (DIP) joint pain, investigating the effects of applying a local anaesthetic solution into the navicular bursa of the afflicted horses. The goal was to understand if the solution would alleviate the lameness caused by the DIP joint pain.

Objective of the Research

• The primary goal of the research was to examine the effects of instilling local anaesthetic solution into the navicular bursa of horses suffering from DIP joint pain. The underlying hypothesis was that the close proximity of the navicular bursa to the palmar digital (PD) nerves might enable the local anaesthetic administered to the navicular bursa to affect the PD nerves, thus potentially relieving pain in the DIP joint and reducing lameness.

Methodology

• Lameness was induced in six horses by creating painful synovitis in the DIP joint of one forefoot via the administration of endotoxin into the joint.
• The horses’ gaits were videorecorded while they were trotting, both before and after inducing lameness, at three distinct 10-minute intervals after administering 3.5 ml of local anaesthetic solution into the navicular bursa, and finally, after instilling 6 ml solution into the DIP joint.
• The researchers then graded the videorecorded gaits subjectively to assign lameness scores.

Results

• The results showed no significant difference in median lameness scores at the 10- and 20-minute observation times after the administration of local anaesthetic solution into the navicular bursa.
• However, lameness scores of three out of the six horses showed an improvement during this period, and at the 20-minute observation, the scores hinted towards a significant change.
• At the 30-minute observation and post the analgesia of the DIP joint, the researchers recorded a significant improvement in the median lameness scores.

Conclusions

• The researchers then concluded that if the lameness in a horse suffering from DIP joint pain is mitigated within 10 minutes of analgesia of the navicular bursa, then the DIP joint pain potentially could be ruled out as a cause of lameness.
• They further concluded that if lameness is reduced after 20 minutes of analgesia to the navicular bursa, pain arising from the DIP joint couldn’t be ruled out as a cause of the lameness.