EFFECTS OF ANESTHESIA OF THE PALMAR DIGITAL NERVES ON KINEMATIC GAIT ANALYSIS IN HORSES WITH AND WITHOUT NAVICULAR DISEASE

Objective-To determine the effect of local anesthesia of the palmar di gital nerves on forelimb kinematics in Quarter Horses with and without navicular disease. Animals-12 adult Quarter Horses; 5 clinically norm al (sound) and 7 with navicular disease. Procedure-Kinematic measureme nts were made on adult horses trotting on a treadmill, before and afte r palmar digital nerve block (PDNB). Twenty-three displacement, joint angle, and temporal gait measurements of the right forelimb and head w ere made for 5 strides in each horse. Initial (before local anesthesia ) right forelimb measurements were obtained after a left forelimb PDNB . Kinematic measurements were compared before and after PDNB of the ri ght forelimb by multiple ANOVA with an alpha = 0.05, adjusted for post hoc comparisons by Bonferroni correction. Results-In sound horses, the only significant change in kinematic measurements after PDNB nerve bl ock was in the maximum extension of the metacarpophalangeal joint at m id-stance, which was decreased by an angle of 2 degrees. In horses wit h navicular disease, mean maximum extension of the metacarpophalangeal joint during stance phase and maximum flexion of the carpal joint dur ing swing phase were significantly increased after PDNB. Also, total s tance phase, cranial stance phase, and break-over durations were signi ficantly shorter. In horses with navicular disease, differences betwee n minimum head heights during stance phase of each forelimb and total vertical head excursion during a complete stride were significantly sm aller after PDNB. Conclusion-Several kinematic measurements of gait ca n be used to determine improvement of lameness in horses with navicula r disease after PDNB block while trotting on a treadmill.