Clinical and ultrasonographic findings in horses with desmopathy of the palmar/plantar abaxial ligaments of the proximal interphalangeal joint: 20 cases.

Abstract

OBJECTIVE: To describe the clinical and ultrasonographic findings in horses with desmopathy of the abaxial palmar/plantar ligament (APL) of the proximal interphalangeal joint and the prevalence of concurrent musculoskeletal injuries in the pastern and foot. ANIMALS: Horses presenting to New Bolton Center between March 2017 and November 2022 with an age ranging from 5 to 20 years that underwent lameness evaluation in which lameness was localized to the distal limb and had an ultrasonographic diagnosis of APL desmopathy. CLINICAL PRESENTATION: Horses included were those that (1) presented for a lameness examination; (2) had lameness that improved after diagnostic analgesia with a low 4-point nerve block (medial and lateral palmar/plantar nerves and medial and lateral palmar/plantar metacarpal/metatarsal nerves), abaxial sesamoid nerve block (medial and lateral palmar or plantar nerves), or palmar/plantar digital nerve block; and (3) had an ultrasonographic diagnosis of APL desmopathy. RESULTS: A total of 20 horses were identified with an ultrasonographic diagnosis of APL desmopathy. Clinical signs in 5 of 20 horses were attributed solely to desmopathy of the APLs of the proximal interphalangeal joint. Concurrent soft tissue and bone injuries were identified in all other cases. CLINICAL RELEVANCE: Given the rare occurrence of APL desmopathy as the sole cause of lameness in the horse, identification of this pathology on ultrasound should prompt continued investigation, particularly in mild cases.