Limited evidence is available relating gait changes to diagnostic anaesthesia. We investigated associations between specific movement patterns and diagnostic anaesthesia of different anatomical structures in a retrospective analysis. Referral-level lameness cases were included with the following criteria: presence of diagnostic anaesthesia of a forelimb and/or hind limb; subjective efficacy classified as "negative", "partially positive", or "positive"; quantitative gait data available from inertial measurement units. Gait changes were calculated for three forelimb (palmar digital, abaxial sesamoid, low 4-point nerve block) and five hind limb diagnostic blocks (tarso-metatarsal, metatarsophalangeal joint block, deep branch of lateral plantar, low 6-point, abaxial sesamoid nerve block). Mixed models (random factor "case", fixed factors "diagnostic anaesthesia type" and "efficacy", two-way interaction) assessed the head and pelvic movement (p < 0.05, Bonferroni correction). Four parameters were significantly affected by forelimb anaesthesia (N = 265) (all p ≤ 0.031) and six by hind limb anaesthesia (N = 342) efficacy (all p ≤ 0.001). All head movement parameters and pelvic push-off asymmetry were significantly affected by the two-way interaction after forelimb anaesthesia (all p ≤ 0.023) and two pelvic movement symmetry parameters by the two-way interaction after hind limb anaesthesia (all p ≤ 0.020). There are interactions between block efficacy and type resulting in changes in weight-bearing and push-off-associated head and pelvic movement symmetry after diagnostic anaesthesia.
Keywords: diagnostic anaesthesia; horse; lameness; movement symmetry; trot.