Any equestrian has watched a horse trot or walk to determine if it's in pain and, if so, which leg. Until now, horse owners and veterinarians have had to rely heavily on visual inspection, but technology from Missouri has developed a device that can detect even the slightest signs of lameness.
The Equinosis Q with Lameness Locator is a handheld device that gives readings based on motion analysis research. A non-invasive inertial sensor is attached to the horse, which is 10 times more sensitive than the human eye, allowing the sensor to detect gait asymmetries that might otherwise be missed as the horse trots in a straight line or lunges in a circle. This makes the device a valuable tool for veterinarians to assess lameness in the field.
The Lameness Locator was developed by Equinosis, a company founded in Columbia, Missouri in 2007. Their goal is to provide this technology to equine veterinarians to improve the quality of care, health, and well-being of horses. The technology was developed through a collaboration between practicing equine veterinarians led by Dr. Kevin Keegan, professor of equine surgery at the University of Missouri, and engineers led by Dr. Frank Pai, professor of mechanical and aerospace engineering. They initially designed an algorithm to assess lameness in horses using a high-speed camera and treadmill-based system. They then worked with the late Dr. Yanezawa Yoshiharu, professor of electrical engineering at Hiroshima Institute of Technology in Japan, to develop a body-worn inertial sensor system with wireless transmission for use in the field.
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Horse Sports spoke with Dr. Crystal Lee to learn more about how veterinary practices use the Lameness Locator. Dr. Lee is an equine surgeon and co-owner of Burwash Equine Services in Calgary, where she has been with the service since 2014. Prior to that, she interned at the University of Missouri, where she worked with Dr. Keegan on the Lameness Locator. Burwash Equine Services introduced their own Lameness Locator shortly after Dr. Lee arrived and has been using it for the past 10 years.
Dr Lee explained that the Lamenace Locator works by attaching three sensors to the horse's neck, the top of the pelvis and the hoof bone (specifically the right front leg).These three sensors are wirelessly connected to a computer which takes real-time readings as the horse trots.
“The sensors on his right front paw just tell him where each paw is and at what time,” Dr. Lee says, “but the sensors on his head and pelvis are accelerometers that measure how much his head and pelvis are rising and falling with each stride.”
In a perfectly healthy horse, the head and pelvis movement is perfectly symmetrical, rising and falling equally with each right and left stride. In an unhealthy horse, the sensor measures the level of asymmetry.
“This gives us a purpose to measure lameness rather than just looking at it, which is subjective,” Dr. Lee says.
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“We implement this into almost every lameness exam because it's really helpful to have an objective measurement,” says Dr. Lee, which not only allows veterinarians to spot more subtle lameness, but also provides an objective number for later re-examinations and to measure improvement over time.
It can also determine whether the lameness is impact or push-off – simply put, does the horse hurt when stepping off the ground (such as navicular syndrome or heel-tail pain) or does it hurt when pushing off the ground (such as suspensory ligament injuries). It's still not black and white, says Dr. Lee, but “sometimes it can guide our work or direct our attention to one area versus another.”
She explains, “This doesn't describe which part of the leg is lame. It helps determine which leg is lame, or which limb is the primary lameness if multiple limbs are lame. But it would be used in conjunction with a nerve block to narrow down which part of the leg is causing the lameness.”
By providing an objective measurement, the Lameness Locator helps reduce confusion regarding the cause of primary lameness which can be difficult to identify. For example, head shaking typically indicates forelimb lameness and hunchback typically indicates hindlimb lameness, however primary lameness may be present in the forelimbs of the body, but with compensatory movements in the hindlimb.
Lameness Locator is only sold to registered veterinarians and used as part of a veterinarian's diagnostic tools or at equine veterinary colleges and research centers. According to Equinosis, there are currently about two dozen private practices and colleges in Canada that use Lameness Locator. (The cost is also steep for the average horse owner; the company wouldn't share a specific figure but said it “varies depending on configuration and should be discussed one-on-one with your veterinarian about your specific needs.”)
Dr Lee says the system shouldn't be used on its own without a veterinarian's expert opinion, but only in conjunction with a full exam: “It's just a tool along with other parts of the exam, but it can give you an objective number that you can use to make some decisions.”
