"Traumatic joint disease is the leading cause of lameness in horses–and it can happen to any horse at any time," said James Casey, DVM, MS, who runs an equine sports medicine and dentistry practice in Laurel, Md. "More than half of all equine lameness is due to noninfectious joint disease and injury. It can happen from one bad step, but it’s most likely due to cyclic (repeated) trauma."

Casey discussed joint disease and lameness for a full house of 303 horse owners at the 2006 Healthy Horses Workshop, held in conjunction with the American Association of Equine Practitioners 52nd annual convention on Dec. 2 in San Antonio, Texas. His main point: Prevent joint disease rather than treating it once it has occurred.

"You don’t wait until your car is completely broken down to get it fixed; you usually get oil changes and maintenance before it gets to that point," he recommended. "Think of veterinary medicine the same way."

For the racehorses he primarily treats, "We usually go through and inject joints as a preventive treatment before and during the seasons," he said. "Not every horse needs that, but if they’re doing maximum performance, it helps maintain health in the joints