Effects of injury to the suspensory apparatus, exercise, and horseshoe characteristics on the risk of lateral condylar fracture and suspensory apparatus failure in forelimbs of Thoroughbred racehorses

abstract: Objective - To assess concurrently the effects of moderate ligamentous suspensory apparatus injury (MLSAI), racing-speed exercise, and horseshoe characteristics on risk of catastrophic suspensory apparatus failure (SAF) or metacarpal condylar fracture (CDY) in forelimbs of racehorses. Sample population - Cadavers of 301 Thoroughbred racehorses (108 with SAF, 33 with CDY, and 160 control horses). Procedure - A cross-sectional epidemiologic study was used to describe distributions and relationships between MLSAI, exercise, and horseshoe variables. Logistic regression was used to assess potential risk factors for developing SAF and CDY. Results - Exercise variables were more highly associated with age than height of a steel bar affixed to the ground surface of the front of a horseshoe (ie, toe grab) or sex. Marginal associations were detected between MLSAI and age and height of toe grab. Higher risk for developing SAF was associated with MLSAI, use of a pad on a horseshoe, longer interval since last period of ≥60 days without a race or timed workout (ie, layup), 2 to 5 career races, and higher intensity of recent exercise. Higher risk for developing CDY was associated with MLSAI, male horses, age between 2 and 5 years, higher intensity of recent exercise, and longer interval since layup. Conclusions and Clinical Relevance - Recognition of MLSAI and rehabilitation of affected horses should reduce incidence of SAF and CDY. Horses in long-term continuous training with recent high-intensity exercise are at greater risk for injury. Use of pads in horseshoes was associated with SAF, although the relationship may not be causal