Sesamoid Bone Studies in Thoroughbred Racehorses

The majority of career-ending health concerns in Thoroughbred racehorses are attributed to musculoskeletal injuries. Very importantly, of these injuries, a small subset can be life-threatening to both horses and jockeys if they occur during high-speed exercise or racing. Although the industry has achieved a reduction in fatal injury rates in Thoroughbred racing over the past decade, understanding the causes and development of lower forelimb bone fractures that lead to these catastrophic musculoskeletal injuries (CMI) remains one of the highest safety and welfare priorities in horse racing. The metacarpophalangeal joint (MCP), widely referred to as the fetlock joint, is the most common site of serious orthopedic injuries in Thoroughbred racehorses. Specifically, significant clinical and research efforts have focused on the proximal sesamoid bones (PSBs), as they account for an estimated 45-50% of fatal injuries among U.S. Thoroughbred racehorses.