Insight: Research Edition

Fall 2006

Preventing Catastrophic Injuries in Horses

At the start of the Preakness Stakes last May, excitement was in the air. The horses were edgy, anticipating the race’s start, including Kentucky Derby winner Barbaro, the horse many thought might be the one to take home the Triple Crown nearly 30 years after the last winner (Affirmed in 1978). Once they were off, within seconds, excitement turned to horror as Barbaro’s right rear leg twisted at a sickening angle and it became clear that he had suffered a life-threatening injury.

Veterinarians later confirmed that Barbaro had experienced a break to his cannon bone above the ankle, a broken sesamoid bone behind the ankle, and a shattered pastern, as well as a dislocation in the ankle joint, or fetlock – all without warning. Dr. Wayne McIlwraith, Director of the Orthopaedic Research Center (ORC) at the College of Veterinary Medicine and Biomedical Sciences, has watched the race tape, as well as seen and treated such catastrophic injuries in many other horses. It’s something that he and his research team are hoping they can prevent from happening to other horses through the development of new diagnostic imaging techniques and fluid biomarkers that will predict and prevent catastrophic injuries before they happen.

“The challenge with many of these horses is there is no obvious evidence before a race that something is wrong,” said Dr. McIlwraith. “In the United States, race track veterinarians evaluate horses before events to determine the fitness of the horse to race. At big races, like the Breeder’s Cup, an inspection team of four veterinarians watches and examines the horses for four days before the Cup. If a horse is lame, it’s pretty easy to see. Jockeys and trainers also monitor their horse’s health. But horses may have other degrees of disease we know occur and lead to these catastrophic injuries, but aren’t apparent at a clinical level.”

Dr. McIlwraith’s group is attacking the problem from multiple angles, including diagnostic imaging techniques, fluid biomarkers and racetrack surface evaluation. Advances in imaging are improving the early diagnosis of injury to soft tissues, articular cartilage and bone. The ORC uses digital radiography, nuclear scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) for clinical cases and research projects. Drs. McIlwraith, Chris Kawcak, Natasha Werpy, David Frisbie and Richard Park are all involved with this work.

“These imaging tools, with the exception of digital radiography and scintigraphy, are not routinely used at the track, so our interest is in developing standards that will allow veterinarians to use something like CT to discern micro-damage and injury potential, as well as working to make CT more practical for use at the track,” said Dr. McIlwraith. “We are using CT to identify bone density patterns associated with various joint injuries, and we hope this work will one day offer veterinarians another tool to improve decision making regarding a horse’s fitness to race.”

The ORC also is actively developing fluid biomarkers, particularly changes in synovial fluid that indicate the presence of early disease, to predict injury. In research sponsored by the Grayson Jockey Club Research Foundation, the ORC has been working in collaboration with racetrack veterinarians in Southern California to evaluate the efficacy of fluid biomarkers in predicting injury. In the California study, Dr. David Frisbie followed 200 horses for 10 months, collecting fluids, serum and blood along the way and correlated biomarker information to incidence of injury. Dr. Frisbie is still processing data from the study, but early results show that biomarkers have real potential as a predictor of injury.

“Our hope is that biomarkers will become part of the routine screening of horses, especially if we have a horse that is suspicious clinically,” said Dr. McIlwraith. “We can use this type of test to confirm that a horse needs to be laid off, sometimes reinforcing the suspicions of the jockey or trainer.”

A third area of research is racetrack surfaces. Dr. McIlwraith is working with Dr. Mick Peterson of the University of Maine and Dr. Raoul Riser of the Department of Health and Exercise Science at CSU to evaluate racetracks with a biomechanical hoof track tester. The tester is used to identify track problems that could potentially cause injury to race-horses. At one particular track in California, the results of track testing were lifesaving. In one six-week period, 24 horses were euthanized and 240 taken off the track because of injury. After testing the track and recommending some changes to how the track was worked, the result was that only two horses were euthanized in the following six weeks.

“Ultimately, we want to improve the overall health of horses, while reducing the incidence of catastrophic injuries,” said Dr. McIlwraith. “Barbaro brought much of the work we do to light, with all the publicity surrounding his injury, and we are hopeful that we can prevent such heartbreaking injuries in the future.”

Barbaro, now more than three months out from surgery to repair his hind leg, continues to recover. He will never be able to race again, but his veterinarians hope he will have a second career as a sire. To learn more about the Orthopaedic Research Center, visit their Web site at www.equineortho.colostate.edu.