Lameness improvement in horses with distal tarsal pain after intra-articular injection of botulinum neurotoxin type A

Abstract

Objective To evaluate the effect of IA injections of botulinum toxin type A (BoNT-A) in horses with chronic, naturally occurrindistal tarsal osteoarthritis. Methods 9 horses were selected after physical and radiographic assessments. Horses also underwent an objective lameness examination and were included if they had a hindlimb impact lameness (Pmin ≥ 3 mm), which positively responded (≥ 50%) to the tarsometatarsal and centrodistal joints’ anesthetic block. Horses randomly received an intra-articular injection of BoNT-A or an equivalent volume of saline solution. Horses were reevaluated at postinjection days (PIDs) 1, 7, 15, 30, 60, 90, 120, 150, and 180. Success criteria included a decrease in Pmin (≤ 3 mm) or an abolishment of lameness on the baseline lame limb with lameness shifting to the contralateral limb. A percentage of lameness improvement was calculated for all horses at all timepoints. Results 5 horses were included in the BoNT-A group, whereas 4 individuals were allocated in the placebo group. A significant improvement (P