Management of chronic foot lameness with 2% ammonium chloride on the palmar digital nerves

Abstract

SummaryThis case series describes the analgesic effect of 2% ammonium chloride (2% AC) in horses with chronic foot pain. Ten horses with foot pain related to chronic laminitis (n = 1), bruised sole (n = 1), distal interphalangeal joint (DIPJ; n = 1), podotrochlear apparatus (PA; n = 4) and PA associated with DIPJ (PA + DIPJ; n = 3) received perineural injections with 3 mL of 2% AC on the palmar digital nerves. A Five horses with pain related to PA + DIPJ (n = 3), PA (n = 1) and DIPJ (n = 1) were treated with saline as control. The analgesic effect was evaluated as lameness improvement (LI) rate (%) using a body‐mounted inertial sensor system, and was assessed at 5, 12, 19, 35, 47 and 62 days after treatment. Horses treated with 2% AC demonstrated a mean LI rate above 50% from Day 12 (63% ± 26) to Day 62 (65% ± 26). Control horses has a overall LI of 28% (± 23%) and a LI above 50% was evidenced in horses with PA + DIPJ (n = 2) and PA pain (n = 1) at different times. Horses with PA pain presented higher LI rates (72% ± 23) than that presented by horses with PA + DIPJ (51% ± 9) or DIPJ (51% ± 19). Horses with severe radiographic lesions of the navicular bone and DIPJ had the lowest LI rates after treatment. The 2% AC is a useful treatment to be included in the clinical management of chronic foot pain involving the podotrochlear apparatus with mild radiographic lesions.