Following the euthanasia of filly Eight Belles, who suffered catastrophic injuries to both front legs a quarter mile after finishing second in the 2008 Kentucky Derby, members of every sector of the Thoroughbred industry have banded together to proactively address safety and welfare issues. In this article, representative members of the equine industry together provide an in-depth exploration of catastrophic injuries in the Thoroughbred racehorse, focusing on what veterinarians know about catastrophic injuries based on the available scientific data, and looking at what work is still to be done.

What are Catastrophic Injuries?

The term “catastrophic injury” in the context of equine veterinary medicine refers to a severe musculoskeletal injury sustained by athletic horses during racing or training that results in an acute lameness. Such injuries include (either alone or in combination):

• Condylar fractures (fractures of the lateral or medial condyle of the third metacarpal bone, also called the cannon bone);
  
• Fractures of the sesamoid bones;
  
• Displaced slab fractures in bones such as the third carpal (in the knee) bone or central tarsal (in the hock) bone;
  
• Rupture of the suspensory apparatus or other tendons or ligaments;
  
• P1 (long pastern bone) fractures/ sagittal fractures (or any fracture of the distal limb); and
  
• Any other bony fractures, including those of the tibia, humerus, pelvis, femur, or stifle.

Isolated musculoskeletal injuries can be successfully managed surgically and, depending on the exact nature of the injury, many of these horses have a good prognosis for return to racing post-surgically following appropriate rehabilitation. Only rarely are these injuries career-limiting, and it is even more uncommon that catastrophic injuries result in humane euthanasia. Injuries involving multiple structures, such as the injuries sustained by horses like Barbaro (who fractured three separate bones in his hind leg and dislocated the fetlock joint in the same limb), are most often life-threatening.

Thoroughbred Injury Rates

Larry Bramlage, DVM, Dipl. ACVS, an equine sugeon at Rood & Riddle Equine Hospital in Lexington, Ky., says, “The Triple Crown, historically, is a very clean (series of races). Before Barbaro we have to go back 15 years to cite the previous injury. From a scientific aspect, two injuries in three years does not constitute an ‘epidemic,’ but rather a heartache for both the equine industry and the casual fan.”

Racing Deaths
LOCATION OF STUDY	FATALITY RATE PER 1,000 STARTs(date of data collection)
California	1.7 (1992)
Kentucky	1.4 (1992-1993)
Florida	1.2 (1995-1998)
Ontario, Canada	2.36, 1.69 (2004, 2005)
United Kingdom	0.8 (1987-1993) and 0.9 (1990-1999)
Victoria, Australia	0.33 (1986-1993) and 0.44 (1989-2004)

According to epidemiological surveys performed in California, Kentucky, Ontario, the United Kingdom, Australia, and Hong Kong, the number of catastrophic injuries incurred by racehorses is small.

“Obviously the entire industry wants the number of catastrophic injuries sustained by Thoroughbreds to be zero,” emphasizes C. Wayne McIlwraith, BVSc, PhD, FRCVS, DSc, Dr. med vet (hc), Dipl. ACVS, Barbara Cox Anthony University Chair and Director of Orthopaedic Research at Colorado State University. “We need to continue to work towards this goal and look at all possible ways of reducing the numbers of injuries.”

Antonio Cruz, DVM, MVM, MSc, Dr. med vet, Dipl. ACVS, ECVS, of the Department of Clinical Studies at Ontario Veterinary College in Canada, recently performed a study on catastrophic injuries in Canadian Thoroughbreds.

“Our research group collected data from two Ontario racetracks in 2004 and 2005 and found that 76 horses were euthanized following the development of catastrophic injuries, which was equivalent to 2.36 and 1.69 fatalities per 1,000 racing starts,” Cruz says.

This data is consistent with other epidemiologic studies. In 1996, Sue Stover, DVM, PhD, Dipl. ACVS, a professor from the University of California Davis School of Veterinary Medicine, and colleagues reported 1.7 fatalities per 1,000 starts in California Thoroughbreds. A Kentucky study co-authored by Noah Cohen, VMD, MPH, PhD, Dipl. ACVIM, currently a member of Texas A&M’s Department of Large Animal Medicine and Surgery, reported 1.4 fatalities per 1,000 starts. In 2001, Mary Scollay, DVM, associate veterinarian at Calder Race Course and Gulfstream Park in Florida, and colleagues reported the incidence of fatality due to catastrophic injuries as 1.2 per 1,000 starts in Florida Thoroughbreds.

In addition, preliminary data collected by Scollay through the new on-track injury reporting system, which came about in 2007 as a result of the first summit on the safety and welfare of racehorses, concurred with these earlier studies.

Scollay’s reporting system was designed to catalog the frequency, type, and outcome of racing injuries in a database capable of identifying horses at risk for injury. Veterinarians in the program are currently looking at data from horses determined to be unsound/unfit for racing by the regulatory veterinarians at 30 different racetracks (a list of the participating tracks is available at www.jockeyclub.com/mediacenter.asp?story=288). These veterinarians are voluntarily collecting data and submitting it to the database using standardized criteria and terminology.

“Using the available data from 2007, the fatality rate of racing Thoroughbreds was 1.47 and 2.03 per 1,000 starts on synthetic surfaces and dirt, respectively,” summarizes Scollay.