West LaFayette, Ind. — Tiny bone cracks caused by rigorous training usually are undetectable in horses before the cracks turn into hairline stress
fractures or more serious problems, like the catastrophic bone failures that led to the deaths of at least three high-profile
Thoroughbreds since 2006 and many others less well-known.
If those microcracks could be detected earlier, alerting veterinarians or trainers that a stress fracture were imminent, the
heavy activity could be reduced or stopped long enough for bones to heal.
Listening to the bones: Whitey, a 14-year-old Standardbred horse, wears a prototype monitoring system while walking on a treadmill
at the Purdue Large Animal Hospital, aided by his trainer, Crystal Hagan, a registered large-animal veterinary technician.
In the background are Ozan Akkus, left, an associate professor of biomedical engineering, and Stephen Adams, a veterinarian
and professor in the Purdue School of Veterinary Medicine.
That's the objective of a new bone-monitoring system researchers at Purdue University are working on. It records "acoustic
emission data," or soundwaves, created by tiny bone fissures — a system like the one seismologists use to record earthquakes,
or like devices that monitor the structural integrity of bridges, buildings and mechanical parts like helicopter blades.
"We are excited about this technology due to its potential to help the horse industry," says Stephen Adams, DVM, MS, Dipl.
ACVS, a professor in the Purdue School of Veterinary Medicine who specializes in equine lameness and surgery. "Though still
in the early stages, we believe it holds great promise."
Adams is working on the project with Dr. Ozan Akkus, an associate professor in Purdue's biomedical engineering department.
"He (Akkus) is the primary investigator. I am helping him with the equine studies," Adams tells DVM Newsmagazine.
"The primary use will be in athletic horses, such as the Thoroughbred, which is the most predisposed to bucked shins, stress
fractures and catastrophic failure of bone. The latter, fortunately, is quite rare, but causes much angst to owners, trainers
and the racing fans," Adams says.
Estimated losses attributed to bone fractures in Thoroughbred or Standardbred horses in the horse-racing industry exceed $10
million annually, and it's also a problem with performance horses.
Veterinarians, trainers and others who worked with the Thoroughbred Eight Belles said the 3-year-old filly showed no signs
of weakness or injury before she collapsed on the track seconds after her second-place finish in this year's Kentucky Derby,
suffering compound fractures of both front legs that led to her euthanization.
Eight Belles was the latest high-profile example, but statistics from a new reporting system show 1.47 fatalities per 1,000
racing starts on synthetic surfaces during the last year, and 2.03 fatalities per 1,000 starts on dirt tracks.
"These horses are running 40 miles an hour, and if there is a microfracture there is danger it will become catastrophic. Currently,
they're not visible on an X-ray," Adams says.
"We hope this technology can help trainers monitor for microcracks so they can tailor their methods to prevent them from worsening.
It may eventually be useful in detecting stress fractures in the back and pelvis, too. These latter fractures may not become
catastrophic, but they can contribute to poor performance."
How far along is the project? "It's in a very preliminary developmental phase. The equipment itself is in prototype," Adams
says. "We know it will detect microcracks in bone when examined in the lab and we have recorded sounds in normal horses. We
have not yet been able to try it on horses with microcracks or stress fractures. So it's a long way from being marketed; three
to five years would be my best guess. The equipment needs to be refined, but it holds much promise."
The researchers believe the technology also can be useful in human medicine, alerting soldiers, athletes, dancers and others
who engage in intensive physical training to the presence of microcracks before they lead to serious injuries. Akkus plans
to visit West Point this summer to test the monitoring system on cadets in basic training.
Patents have been filed, and the Purdue Research Foundation's Office of Technology Commercialization is working with Adams
and Akkus to move the technology to market.