Lameness evaluations can be extremely subjective. When examining a horse with a mild lameness, in particular, veterinarians often don’t agree on a diagnosis—some are prone to seeing a more sound horse, others a more lame one. To overcome such disparities, practitioners have turned to objective methods such as force plates and inertial sensor systems (e.g., the Lameness Locator). But which is superior: a subjective exam or one of these devices?

At the 2014 American Association of Equine Practitioners Convention, held Dec. 6-10 in Salt Lake City, Utah, Josh R. Donnell, DVM, equine sports medicine and rehabilitation resident at Colorado State University’s Orthopaedic Research Center, in Fort Collins, compared the force plate to the inertial sensor system (ISS) and to two different forms of subjective evaluation: unblinded and blinded.

A force plate measures ground reaction forces that reveal how well a horse is loading the limb as he trots over the stationary plate. A horse loads a painful (lame) leg less than a sound leg. The force plate is limited, however, in that it only measures a single stride, said Donnell.

The ISS detects asymmetry of the head, pelvis, and limbs while a horse trots. The device’s benefit is that it can be used on any surface in any environment or terrain and can record continuous strides, he said