The Horseracing Integrity and Safety Authority (HISA) has released a new Equine Health Advisory highlighting key risk factors for fatal proximal hindlimb fractures in Thoroughbreds. Based on data from the HISA Portal, the advisory offers guidance to trainers and veterinarians to prevent these injuries. It reports 28 such fatal fractures in 2024 and 2025, mostly during training.
The Horseracing Integrity and Safety Authority (HISA) announced on Thursday, February 26, 2026, the release of its third Equine Health Advisory, focusing on fatal proximal hindlimb fractures in Thoroughbreds. This advisory follows previous ones on proximal forelimb fractures and exercise-associated sudden death, emphasizing data-driven approaches to equine safety.
Drawing from reports in the HISA Portal, regulatory veterinarians at covered racetracks documented 28 fatal fractures in 2024 and 2025: 12 tibial and 16 pelvic bone fractures. Of these, 75% occurred during training, while 25% happened during racing.
Key risk factors include limited high-speed exercise. Approximately 40% of affected horses had 10 or fewer high-speed furlongs recorded in the 60 days before the fracture. For fatal tibial fractures specifically, 40% of horses had zero lifetime high-speed furlongs, and 50% had 10 or fewer in the prior 60 days. About 15% of these horses—four in total—had been listed as unsound by veterinarians at least once in the previous year. Additionally, two unraced horses, aged 4 and 5 years, suffered fatal tibial fractures.
Fatal pelvic bone fractures predominantly affected fillies and mares, with 80% of cases in females, whereas tibial fractures were more evenly distributed across sexes. The data indicates that insufficient high-speed exercise, such as in horses starting training or returning from layoff, increases risk, similar to patterns seen in forelimb fractures.
"It’s important that HISA utilizes the data we collect to draw insights and share learnings with the industry," said Dr. Jennifer Durenberger, HISA Director of Policy and Industry Initiatives. "This advisory, like the proximal forelimb fracture advisory, aligns with HISA’s commitment to data-driven safety and education among industry stakeholders."
The full advisory has been distributed to registered trainers and veterinarians via the HISA Portal and is available on www.hisaus.org under Resources.
