It was back in 2005 when researchers at Texas A&M University linked barrel horses with forelimb lameness. In a study published in the Journal of the American Veterinary Medical Association, the researchers said that horses competing in barrel racing events were much more likely than horses in other disciplines to develop forelimb lameness and attributed the problem to the fact that barrel horses are required to make sharp turns while traveling at a high rate of speed, which often overloads the limbs.

But it wasn’t the only study that addressed the issue. “Lameness is the most common cause of poor performance in sport horses,” wrote Rustin Moore, DVM, director of the Equine Health Studies Program at the School of Veterinary Medicine at the University of Louisiana.

“Lameness typically results from pain associated with the musculoskeletal system, including abnormalities with joints, bones, tendons, ligaments and muscle. The majority of cases of lameness are localized to areas within the distal limb; however, the sources, causes and locations of lameness are diverse. Lameness can be caused by numerous and diverse conditions, including but not limited to wear-and-tear, overuse and trauma,” Moore wrote.

“The diagnostic approach to lameness in horses should involve consideration of the signalment (age, breed and sex), pertinent medical history, past and present use of the horse, physical examination, lameness evaluation and ancillary diagnostic procedures.”

Although it is widely considered to be the main contributor to poor performance, lameness can be difficult to determine and diagnose. Many veterinarians considered experts in lameness evaluations often cannot concur on a diagnosis when examining the same horse.

A contributing variable is the development of secondary lameness in a horse once the primary lameness is detected. This issue can further complicate the treatment plan.

Enter the Lameness Locator

“There are a lot of cases of secondary lamenesses in other legs,” explained Kevin Keegan, DVM, a professor of equine surgery in the College of Veterinary Medicine at the University of Missouri. “If you eliminate the primary problem you don’t have to chase that because it’s going to get better on its own.”

During his residency and throughout his professional career, Keegan has paid close attention to how lameness issues were diagnosed and decided to compile his own data, then determine how to proceed in improving the process.

“We started measuring lameness in about 1993 and did it until 1998,” Keegan said. “We put markers on horses and filmed them with high-speed cameras, commercially available gait analysis equipment and a treadmill. It was a slow process and we really didn’t know what we were going to measure. People who had done similar work measured things like stride length, joint angle changes, head movement, pelvic rotation and other kinds of things, so we went to computer engineers, and they told us they would use the data we collected to generate different algorithms to search for the best indicators of lameness.”

Keegan’s research, grant requests, revisions and partnership with Frank Pai, a mechanical engineer professor at Missouri University, and Yoshiharu Yonezawa at the Hiroshima Institute of Technology in Japan, morphed into a device dubbed the Lameness Locator, available to veterinarians via the company Equinosis.

The equipment consists of an inertial sensor system that measures internal vibrations while the horse is trotting in a straight line. The sensors are placed on the horse’s head in the halter or a head bumper, the midline of the pelvis and in a right front pastern wrap.

Blue Tooth technology transmits the data to a PC tablet downloaded with specific software, which composes the information and can be ready for evaluation before the veterinarian has completed his or her physical examination.

“When we started out, we were just going to develop something to use here at the clinic and for teaching, but it just kind of developed into something around 2002 or 2003 where we thought it might be useful to other people,” Keegan said.

Although the Lameness Locator was never intended for commercial use, Keegan and his partners developed the first prototype in 2009, and it was distributed to “early adopters” for testing and feedback. The Lameness Locator was first marketed commercially in early 2010, and Keegan estimates that 90 domestic veterinary practices, along with some universities, have purchased the equipment.

“A horse had to have a significant amount of lameness to sense differences in joint angle and stride length, and we received the highest correct classification if we concentrated on vertical motion of the torso,” Keegan said. “They call this vibration analysis, and I think they specifically call it fault detections analysis. They use it for finding cracks in structures like beams and buildings and airplane wings. When a horse trots, it includes acceleration and deceleration, so the vibration analysis looks at the motion or vibration, dissects it and finds where the fault is affecting the vibration. For instance, you can tell where the crack in the structure is by stimulating the vibration.”

Duncan Peters, DVS, of Hagyard Equine Medical Institute in Lexington, Ky., was one of the Lameness Locators’ first group of test users and feels that the equipment is a useful tool in his practice.

“There is definitely a learning curve as with any new technology, but it’s relatively simple and easy to incorporate in your exam,” Peters said. “I think it’s as user-friendly to the horses as it is to us. We’ve had a couple horses that think it’s a big fly on their rump and have kicked up a couple times, or you might get one that shakes his head because he doesn’t like the bonnet, but that’s few and far between.”

Dr. Jessica Morgan of Morgan Equine Veterinary and Farrier Hospital in Lockport, N.Y., purchased the Lameness Locator shortly after the technology became available. Morgan says that it has reduced the time necessary to figure out what problems are primary limb lameness versus secondary issues. She said it has also reduced the amount of time necessary to perform a lameness evaluation as well as cost to the client.

Morgan conducts her lameness evaluation in two parts: one while the horse is in motion and the other while at rest. She begins by putting a horse through three trials on a straightaway at a trot on a hard surface such as asphalt and then watches how they move over a firm surface lunging left and right at the trot.

The horse is then brought back into the hospital, where Morgan performs the physical, or static, part of the evaluation.

“I actually try not to get a lot of history from the clients because I like to see horses as they are today without a lot of perceived notions before we put the Lameness Locator on them,” she said. “Once I have a clinical picture, then I assimilate the data on the horse and how everything goes together. When I describe to the client what my findings are, it’s most often exactly what they are seeing. They are often surprised I can figure out what the primary issue is and which is the secondary issue.

“From there we can get right down to business and get started on a diagnostic plan, meaning which leg to block, and so forth. The amount of time it takes for me to do an exam from the time a horse pulls into the driveway until we start talking about diagnostics is probably only about 25 to 30 minutes.”

Keegan acknowledges that there are many veterinarians who are unaware that the Lameness Locator exists.

“There might be some veterinarians out there who think this is a gadget, a toy,” Keegan says, noting that the National Science Foundation has provided three grants for the project. “Our biggest challenge now is to introduce this to veterinarians, train them on proper usage and interpretation of the data and show them this really works.”

Kimberly French is a freelance writer who resides in Louisville, Ky. She contributes to various equine publications but has a special place in her heart for horses involved in any sort of racing. E-mail comments on this article to [email protected].




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