Affiliation:
1. William R. Prichard Veterinary Medical Teaching Hospital, University of California Davis California USA
2. Department of Surgical and Radiological Sciences School of Veterinary Medicine, University of California Davis California USA
3. Equine Medical Center Cypress California USA
Abstract
AbstractBackgroundCondylar fractures are a major cause of morbidity and mortality in Thoroughbred racehorses. Condylar fractures have a variety of fracture configurations that suggest there may be differences in aetiopathogenesis.ObjectiveTo determine if exercise history differs with condylar fracture location in a population of Thoroughbred racehorses.Study designRetrospective analysis of clinical and exercise data.MethodsExercise history of Thoroughbred racehorses that had condylar fracture repair between 1 January 2018 and 28 February 2021 was compared between racehorses that had fractures located radiographically either within the parasagittal groove (PSG) or abaxial to the PSG (non‐PSG). Age, sex, and last event (race, timed work) matched control groups were compared between the PSG and non‐PSG groups. Additionally, exercise history variables of both groups were each compared with a group‐specific control population, each consisting of three control racehorses of equivalent age and sex matched to each affected racehorse by last event (race or official timed work) before fracture.ResultsEighty‐two horses with 84 fractures (45 PSG, 39 non‐PSG) met inclusion criteria. Age was not different between groups (PSG: 3.4 ± 1.3 years [mean ± SD], non‐PSG: 3.7 ± 1.3, p = 0.3). Number of races (PSG: 5.3 ± 7.1, non‐PSG: 11.4 ± 8.9, p < 0.001), total race furlongs (PSG: 38.2 ± 54.7, non‐PSG: 79.2 ± 64, p = 0.003), and number of active days (PSG: 304 ± 224, non‐PSG: 488 ± 314, p = 0.003) before fracture were greater; while mean number of layups was fewer (PSG: 1.0 ± 1.2, non‐PSG: 0.5 ± 0.7, p = 0.02) in horses with non‐PSG fracture. Horses with non‐PSG fracture had more differences compared with their respective control group than horses with PSG fractures. Outcomes following fracture repair were not different between groups.Main limitationsRetrospective study, one regional racehorse population, two‐dimensional imaging and potential inherent bias for fracture localisation, low statistical power for return to performance analysis.ConclusionsThoroughbred racehorses with non‐PSG condylar fractures have a more extensive exercise history than horses with PSG condylar fractures, suggesting differences in fracture aetiopathogenesis.