In Top Form
Every time an athlete is referred to the Issam M. Fares Equine Sports Medicine Clinic, a full arsenal of diagnostic strategies can make all the difference in returning the horse to action.
Some athletes are prized for their track speed or cross-country hunting and jumping skill. Others for their strength, agility, and grace to perform the myriad tasks required in equestrian events like show jumping or dressage, not to mention a fast-paced polo match. Any horse that performs and competes with its rider, from a 4-H pony to a Derby winner, qualifies as an equine athlete. And just like their human counterparts, sport horses can push their bodies more than nature might have intended, sometimes resulting in problems that impede their performance or sideline them. That's where equine sports medicine comes in.
"We're asking our horses to perform as a professional athlete would, and in fact our life depends on it when we're on the horse," comments Stephen Browne of the Norfolk Hunt Club. "Owners spend a lot of time training a horse so that it learns its job; they might hunt with the same horse for 10 years. So they spend a fair amount of time, effort, and money in caring for it." For Browne's hunter-jumper, that means keeping him fit and in good condition so both can enjoy a three-or-more-hour event such as the club's annual fall drag hunt. "You can't just have him sit around the barn all summer and then jump on him one day and expect that he's going to be able to perform, because then you will get hurt," he stresses. Keeping a performance horse fit requires a careful program of exercise and training several times a week, and that can be a challenge during long New England winters when one is limited to the indoors. Finding the time also poses a challenge since most competitive riders, Browne points out, have regular day jobs.
Spotting the signs
Good maintenance also requires spotting trouble signs early. Knowing what to look for, and distinguishing between minor and more serious injury, requires close communication between the owner and/or rider, trainer, and barn manager. A complicating factor is that equine athletes often travel to compete, and therefore might see a handful of different veterinarians during the year. "The key is to make sure that information gets passed along if there's a concern," says Dr. Katherine Chope, VMD, who performs diagnostic ultrasound at the Cummings School's Hospital for Large Animals, including the Equine Sports Medicine Clinic. "Experienced horsepeople at 'ground level' can tell whether or not a swelling, a gait, or a behavior requires veterinary care," adds Chope, a former show jumping competitor. Just as with humans, though, making the call between letting the athlete compete or sidelining him can be tough.
Garcia-Lopez examines a patient.
When a veterinarian refers an equine patient to the clinic, having a fully-rounded arsenal of diagnostic strategies makes all the difference in returning that athlete to top form. Lameness may be the most obvious condition affecting a horse's performance, but medical conditions like a cardiac or respiratory ailment can also be the culprit. Inflammatory airway disease (IAD), for example, impedes a horse's ability to breathe while exercising or performing, which can lead to exercise intolerance. IAD stems from a high-dust stabling environment, according to studies conducted by Dr. Andrew Hoffman, head of the Lung Function Laboratory, and Dr. Melissa Mazan, V93, director of the Issam M. Fares Equine Sports Medicine Program. Their work has involved examining both the environment and the horse to analyze how dust enters and injures the lower airway. Mazan is also working at the cellular level to understand the mechanisms that trigger asthma.
In addition to research, clinical advances have made a huge difference in the large animal hospital's ability to characterize, diagnose, and treat respiratory disease. Mazan cites diagnostic imaging, particularly ultrasound, as an invaluable aid for respiratory problems such as pneumonia, which can occur among young horses and others with weakened immune systems who are frequently shipped long distance, notes Chope. She also uses ultrasound to diagnose (or rule out) colic, chronic weight loss, suspected kidney or liver problems, and tumors. Another versatile diagnostic tool is the clinic's high-speed treadmill, used to help diagnose respiratory and other medical conditions as well as lameness. "We use a combination of ultrasound and the treadmill, together with EKGs, to determine cardiac problems," explains Dr. José García-López, VMD, one of four veterinary surgeons in the Equine Sports Medicine Clinic. Upper airway evaluations often require endoscopy; in fact, a recent visit to the clinic found García-López coaching a resident and a fourth-year student to use an endoscope to examine the upper airway of a racehorse. Lower airway problems are the purview of the Lung Function Laboratory, the first center in the U.S. to institute routine lung function testing in clinical patients.
A battery of tools
Musculoskeletal injuries—primarily subtle foot issues like suspensory ligament problems—are often the reason veterinarians refer equine athletes to the clinic. Chope and García-López—who happen to be one of Cummings' husband-and-wife teams—typically see low-grade, nagging performance issues that can be hard to pin down. Cummings' soon-to-be upgraded outdoor longeing (rhymes with "sponging") ring is often the first step in starting to zero in on the location of an injury. The horse walks, trots, or canters around the inside perimeter of the ring, guided by a line held by a handler in the middle of the ring, while clinicians observe its gait.
Homing in on an injury usually requires one or more of a battery of imaging tools at the Cummings hospitals. Today's sophisticated technologies allow equine specialists to confirm, or at least gain a higher degree of certainty about, subtle injuries in smaller ligaments in the leg that they might have merely suspected in the past. And having all these diagnostics at their fingertips allows clinicians to choose the best one for the situation. Now that the hospitals' CT is set to receive a new custom-designed table for large animals, García-López expects it will be particularly helpful in viewing body cavities such as sinuses and tooth roots, bone, and even the brain, especially with foals. Cummings' brand-new powerful 1.5-tesla MRI, which saw its first equine patients last summer, increases the clinic's ability to evaluate soft-tissue areas—tendons and ligaments—as well as bone and joint areas. "Being able to take horses in our MRI unit is really amazing," says Chope. "There aren't that many units of this high strength in the country. It should make a huge difference, particularly for foot problems."
A bone scan, done with the aid of nuclear scintigraphy, is another important tool, a highly sensitive technology that affords a broad view of the entire skeletal system of the horse. It highlights abnormal areas that can then be explored in greater detail, typically with radiograph or ultrasound. This approach recently benefited a horse referred to Cummings by Backstretch Veterinary Associates, a Sherborn, Mass.-based equine practice owned by Dr. Suzanne Loheac, V98. The patient was acutely lame in her hind leg, and no amount of nerve blocking would allow Loheac and her colleague to pinpoint the source. "She had some nerve branches we just couldn't reach," she surmises. "We couldn't even get her to improve. It was just odd." So odd, in fact, that they feared the problem might originate in her hip or pelvis. But at the large animal hospital, nuclear scintigraphy "lit up her navicular bone really bright," says Loheac. Radiographs taken from several different angles ultimately found a break, and ultrasound revealed additional damage to the surrounding area. The injuries were treated and the horse appears to be on the mend.
Good choices—and tough ones
The ability to choose the right diagnostics—or combination thereof—makes it easier for equine specialists to distinguish earlier between conditions with vastly different treatments, such as soft tissue injury and bone pain. Both can produce similar symptoms, but soft tissue injuries require rest, whereas resting horses with bone pain can actually worsen the problem. Another benefit, notes García-López, is that "we now have the ability to decide which order to use them in, to get the most out of one or the other. Potentially we can use them all, but we won't if we can get the job done with just one." Because of the cost of an MRI, for example, he'll typically start with more affordable technologies and move progressively into other strategies as necessary to reach a diagnosis. On the other hand, it can be more cost efficient to go directly to MRI "if we have a suspicion that none of the other technologies are going to be conclusive—like with this horse right now," says García-López. He indicates a horse in the process of being anesthetized and shifted to the MRI table. It's a job that takes seven people, all of whom look to be breaking a sweat.
Dr. Bryan Parrott, V87, of Parrott Equine Associates, appreciates that kind of thoughtful decision-making. He has the capability and the technology to perform standard and digital radiography, ultrasound, and endoscopy at his Hamilton, Mass., clinic, but refers patients to Cummings for in-depth evaluations of particularly unusual cases. When he does, "I feel confident that they'll be treated by people who answer to a higher calling. I'm not worried that my clients will get services they don't need." Parrott is concerned, however, that the number of available options presents the challenge of knowing when enough is enough. His clients tend to consider their horses as members of the family, even supporting their geriatric companions for years at retirement farms in the South. "The amount they will spend on their animals is extraordinary, often putting themselves in financial jeopardy. With so many options, both medical and financial, to think about and weigh, it's a huge challenge to advise them." He notes, however, that the number of clients with equine medical insurance has sharply risen over the past several years.
As diagnostic capabilities advance in tandem with imaging technologies, clinicians will be able to focus with more and more clarity on other areas of the horse's musculoskeletal structure, such as its spine, neck, and sacroiliac regions. Chope expects the MRI "to open up a lot of the foot problems. Ultrasound also has some applications in the foot, so by having both of these, we'll be able to refine both techniques better." The technology can also aid treatment: she uses ultrasound to guide an injection—to direct a therapy as precisely as possible to the site—and to perform guided biopsies. With respect to prevention, the primary front is as it's always been: good horsemanship. "I don't know if we have ways yet of saying we'll prevent any of these sports injuries from occurring," states Chope, "but at least we're now starting to be able to pick up on problems before they become career ending, or require a year off, or require an expensive surgical procedure. And that is key."
Profile written by Leslie Limon
Photos by Melody Ko, Tufts Photo
This story originally appeared in the Winter 2007 issue of Tufts Veterinary Medicine. It ran online on Jan. 28, 2008.