Comparison of lameness scores after a low 4‐point nerve block to lameness scores after additional desensitisation of the dorsal metatarsal nerves in horses with experimentally induced pain in the metatarsophalangeal joint

Abstract

SummaryThis study evaluated whether anaesthesia of the dorsal metatarsal nerves in addition to a low 4‐point nerve block provides significantly more analgesia to the metatarsophalangeal joint than to a low 4‐point nerve block alone. A wireless, inertial, sensor‐based, motion analysis system was used to evaluate gaits of six horses before induction of lameness, after administration of interleukin‐1β into a metatarsophalangeal joint, after anaesthesia of the medial and lateral plantar nerves and the medial and lateral plantar metatarsal nerves, and after additional anaesthesia of the lateral and medial dorsal metatarsal nerves. The magnitude of hindlimb lameness was analysed considering both the push‐off component (diffmaxpelvis) and the impact component (diffminpelvis) of the lame limb for all trials. There was no significant difference in the sum of diffmaxpelvis and diffminpelvis (SDMPs) when comparing the horse's gait after the low 4‐point nerve block to the gait after additional anaesthesia of the dorsal metatarsal nerves, indicating that there is likely no benefit of medial and lateral dorsal metatarsal nerve anaesthesia when using regional anaesthesia to localise pain to the metatarsophalangeal joint during a lameness examination.