Researchers recently found that Western performance horses can show signs of bone stress in their fetlocks similar to those seen in Thoroughbred racehorses, even though they compete in a very different sport.

In the largest study of its kind, scientists reviewed radiographs (X rays) from 90 Western performance horses with lameness isolated to the fetlock joint and found bony lesions in about 97%. Most of these changes appeared to result from exercise-induced bone remodeling that went awry—though not typically in ways that cause catastrophic fractures like those sometimes seen in racehorses. The findings highlight the need to recognize the fetlock joint as a common source of lameness in Western performance horses and to better understand bone changes unique to their disciplines, said Gabrielle Solum, DVM, MS, of the Orthopaedic Research Center in Colorado State University’s Department of Clinical Sciences, in Fort Collins.

“My biggest practical message is to just not overlook fetlock pain in general,” Solum said. “I speak with clients a lot who’ve had their horses’ coffin joints injected multiple times, and they’re not seeing results. Often, those horses just need a little further workup—including a closer look at the fetlock.”

Solum said she and her colleagues have noticed many Western horses go sound after an intra-articular block in the fetlock—pointing to fetlock-specific pain. Yet most of the research on this topic focuses on Thoroughbreds, whose high-speed, straight-line work creates very different stresses on the fetlocks than the tight turns and repeated maneuvers of Western performance horses.

Reviewing Western Performance Horse Lameness

To fill that knowledge gap the team reviewed 11 years of health records from 90 Western performance horses diagnosed with fetlock lameness at Equine Sports Medicine in Pilot Point, Texas, from 2012 to 2022. Two-thirds of the affected joints were in the forelimbs. The horses, mostly Quarter Horses with some Paints and Appaloosas, underwent detailed radiographic exams that were later reevaluated by a board-certified equine radiologist.

Common Causes of Lameness in Western Performance Horses

Only three horses had no visible changes on radiographs, Solum said. The most common findings—seen in more than half of the horses—included areas of increased bone density (sclerosis) in either the lower cannon bone or the top of the long pastern bone (P1). These changes can make bone less able to absorb shock and suggest maladaptive remodeling. Many horses also had extra bone growth along joint margins and thickened soft tissues around the area, which could indicate tendon or ligament strain or inflammation. The researchers often saw changes in the bone layer just beneath the joint surface, too.

While Western horses don’t tend to develop the stress fractures that can precede catastrophic injuries in Thoroughbreds, said Solum, the lesions most often seen in them resembled the maladaptive bone remodeling seen in racehorses—likely reflecting how their own sports challenge the fetlocks.

“Most of these horses will compete several times, or even every day, during a two-week horse show,” she said. “They’re not competing at speed like racehorses, but they’re doing more repetitions per day, and I think they just have way more repetition on those joints than other sports do.”

Radiographic findings didn’t always match the horses’ lameness scores. That’s not surprising, said Solum, because radiographs can’t always show how active—or painful—a condition really is. Still, horses with sclerosis or fissures in P1, or with subchondral bone cysts, tended to show more severe lameness. These kinds of changes might develop when bone doesn’t adapt well to chronic stress, she added, and could be key areas to examine closely during lameness workups in Western performance horses.

Applications in Practice and Future Research

The study results could help veterinarians better recognize underdiagnosed fetlock problems and improve how they image and assess these cases.

“Just look for those more subtle changes in fetlock joints, because things like P1 sclerosis can be a really painful thing,” Solum said. “I hope that this is just a jumping-off point for this topic, and that it’s not the end of the topic because I really think that it’s just scratching the surface of a knowledge base here.”

The study, “Western performance horses with fetlock lameness demonstrate radiographic evidence of chronic exercise remodelling,” appeared in Equine Veterinary Journal in May 2025.