Arthritis can cause the joints to be hot, painful and swollen, although horses can still have arthritis without these signs. In horses the most common and important type of arthritis is osteoarthritis.

Osteoarthritis is a specific form of arthritis that involves a progressive destruction of articular cartilage—the specialized tissue that lines the ends of the bones inside the joint. Equine OA is the most common cause of lameness in horses. Recent estimates show that approximately 60 percent of lameness problems in horses are related to OA.

In arthritic joints, the cartilage physically degenerates over time. There is no cure for osteoarthritis. Instead, the goal for managing horses diagnosed with OA is to slow the disease’s progress.