REASONS FOR PERFORMING STUDY: Anaesthesia of the palmar digital nerves is claimed to attenuate lameness in some horses that are lame because of pain in the proximal interphalangeal (PIP) joint. OBJECTIVE: To determine the response of horses with pain in the PIP joint to anaesthesia of the palmar digital nerves. METHODS: Horses were video recorded trotting before and after induction of pain in the PIP joint and 10 mins after anaesthesia of the palmar digital nerves. The palmar digital nerves were anaesthetised 3 times at different sites, and the video recorded gaits were scored subjectively. RESULTS: The median lameness score of gaits after administration of 2% mepivacaine 1 cm proximal to the cartilages of the foot was not significantly different from the median lameness score before anaesthesia of the palmar digital nerves (P > or = 0.05), although that of 1 of 6 horses improved markedly. The median lameness score was significantly (P < or = 0.05) improved after mepivacaine was administered 2 and 3 cm proximal to the cartilages of the foot. CONCLUSIONS: The PIP joint is unlikely to be anaesthetised when the palmar digital nerves are anaesthetised at the proximal margin of the cartilages of the foot. POTENTIAL RELEVANCE: Pain within the PIP joint cannot be excluded as a cause of lameness when lameness is attenuated by anaesthesia of the palmar digital nerves at any site proximal to the proximal margin of the cartilages of the foot.
Available at: http://works.bepress.com/james_schumacher/86/