High-field magnetic resonance imaging enables diagnosis of central tarsal bone fractures in performance horses with lameness localized to the proximal metatarsus and tarsus

Abstract

Objective Central tarsal bone (CTB) fractures are challenging to diagnose, and cross-sectional imaging is required for definitive characterization and surgical planning. This retrospective case series aims to provide the first description of high-field (3-T) MRI characteristics of CTB fractures, concurrent pathology, and clinical presentation in 8 performance horses. Animals 8 horses (9 limbs) diagnosed with a CTB fracture on high-field MRI at one tertiary referral hospital between 2013 and 2023 were identified via electronic medical records search. Clinical Presentation Quarter Horses (6 of 8) used for Western performance disciplines, a Lusitano (1 of 8) used for Dressage, and a Thoroughbred (1 of 8) used for polo, with ages ranging from 3 to 20 years (mean, 8.4 years), were included. Lameness onset was chronic in the majority of cases (5 of 8), with grades ranging from 3/5 to 4/5. Lameness was localized to the proximal metatarsus (4 of 6), distal tarsal joints (1 of 6), or tarsocrural joint (1 of 6). A suspected CTB fracture was identified on radiographs prior to MRI in only 1 limb. Results Fractures were complete (6 of 9) or incomplete (3 of 9) with a dorsomedial to plantarolateral orientation occurring from 36° to 62° medial to the sagittal plane (mean, 52°). There was severe sclerosis (9 of 9) and mild (4 of 9), moderate (4 of 9), or severe (1 of 9) bone edema–like signal associated with all fractures. Clinical Relevance High-field MRI enabled diagnosis and detailed evaluation of CTB fracture configuration and concurrent bone and soft tissue pathology. Dorsomedial-plantarolateral oblique radiographic projections at approximately 50° medial to the sagittal plane may improve initial CTB fracture identification in performance horses.