Frequency of and risk factors associated with catastrophic musculoskeletal injuries in Quarter Horses at two Midwestern racetracks: 67 cases (2000-2011).

OBJECTIVE: To determine the incidence and anatomic location of and potential risk factors for catastrophic musculoskeletal injuries (CMIs) in racing Quarter Horses. DESIGN: Retrospective matched case-control study. ANIMALS: 67 racing Quarter Horse racehorses euthanized because of CMIs and 134 matched controls. PROCEDURES: Data for Quarter Horses that sustained CMIs and the total number of race starts for each year were obtained from 2 Midwestern racing jurisdictions from 2000 through 2011. Information for each horse with a CMI and for 2 randomly selected control horses that ran in the same race but did not incur a CMI were obtained from race records, past performance reports, and video analysis. RESULTS: There were 61,797 race starts and 82 CMIs from 2000 through 2011 at the 2 racetracks studied, for an overall CMI incidence of 1.33 CMIs/1,000 starts. Sixty-seven horses with CMIs for which complete data were available and 134 matched control horses were included in the study. There was no difference in the incidence of CMIs between the 2 racetracks or over the years studied. The right forelimb was injured in 38 of the 67 (56.7%) horses. Injures to the carpus (24/67 [35.8%]) and metacarpophalangeal joint (fetlock joint; 23/67 [34.3%]) occurred most frequently. Case-control data indicated that the horses with a CMI had fewer starts, were more likely to have stumbled at the break, had a more erratic stride, were fatigued, and trailed in the race, compared with matched controls from the same races. Irrespective of race distance, most of the horses (47/67 [70.1%]) were injured after or within 10 yards before the finish line. CONCLUSIONS AND CLINICAL RELEVANCE: The results of the present study may aid in the identification of racing Quarter Horses at risk for CMIs. The cluster of injuries near the finish line provides a specific focus for future research into methods of injury prevention in this population of racehorses.

Evaluation of catastrophic musculoskeletal injuries in Thoroughbreds and Quarter Horses at three Midwestern racetracks.

OBJECTIVE: To determine the incidence of and compare the types of catastrophic musculoskeletal injuries (CMIs) sustained in Thoroughbreds and Quarter Horses during racing at 3 Midwestern racetracks from 2000 to 2006. DESIGN: Retrospective cohort study. ANIMALS: 139 Thoroughbred and 50 Quarter Horse racehorses euthanized because of CMIs. PROCEDURES: Veterinary officials from 3 Midwestern racing jurisdictions provided injury reports for Thoroughbreds and Quarter Horses that sustained CMIs (which required euthanasia) and the total number of race starts for each year. The number of CMIs/1,000 starts was determined for each racetrack. Past performance reports for each horse with a CMI were evaluated. RESULTS: The total number of race starts (both breeds) at the 3 racetracks from 2000 through 2006 was 129,460, with an overall incidence of 1.46 CMIs/1,000 race starts. Incidences of CMIs among racetracks were similar. Of horses that sustained a CMI, the median age of Thoroughbreds at first race was 3 years, compared with a median age of 2 years for Quarter Horses. A larger proportion of Thoroughbreds sustained a CMI in a claiming race than did Quarter Horses, and a larger proportion of Quarter Horses sustained a CMI in a futurity trial than did Thoroughbreds. The most common site for CMIs in Thoroughbreds was the left forelimb (69/124 [55.6%]), whereas most CMIs in Quarter Horses involved the right forelimb (18/30 [60.0%]). CONCLUSIONS AND CLINICAL RELEVANCE: Differences identified between CMIs in Thoroughbred and Quarter Horse racehorses should allow veterinarians to focus on horses and anatomic regions of greatest risk of CMI during racing.