Many equine athlete owners worry about bone and joint problems as their four-legged partners age. But these issues are just as important in young developing horses as they are in mature horses. One of the most common and potentially damaging developmental orthopedic disorders is osteochondrosis. Earl M. Gaughan, DVM, Dipl. ACVS, clinical professor of large animal surgery at Virginia Tech's Virginia-Maryland Regional College of Veterinary Medicine, discussed this common developmental orthopedic disease at the 2012 Western Veterinary Conference, held Feb. 19-23 in Las Vegas, Nev.

Gaughan explained, "The overarching umbrella term 'osteochondrosis' appears to apply to the results of abnormal endochondral (within cartilage) ossification," or, simply put, the process by which soft cartilage cells transform into hard bone cells. He described several locations within the equine body that osteochondrosis favors:

• A joint surface or in subchondral bone (under the bone surface within a joint); these lesions are termed osteochondritis dissecans (OCD);

• Deep beneath a joint's surface (called subchondral bone cysts); and

• At the physes (growth plates) of long bones and vertebrae.

Although osteochondrosis is considered a developmental orthopedic disorder, not all lesions develop on the same "schedule," Gaughan said