Review of Patterns of Humeral Fracture in Thoroughbred Racehorses

1. Introduction
Musculoskeletal injury is the most common cause of death in racehorses.¹  In a study of California racehorses that died between 1990 and 1992, 83% of horses died because of musculoskeletal injuries.¹  Concern about horse welfare and wastage, jockey injuries, and public perception of Thoroughbred racing has influenced researchers to study the potential causes of catastrophic musculoskeletal failure in Thoroughbred racehorses. Increased knowledge may improve understanding of the pathogenesis of injuries and enhance opportunities for injury prevention. The humerus is the third most commonly fractured bone in Thoroughbred racehorses that die during training sessions.¹  Previous studies have attributed racehorse catastrophic fracture occurrence to pre-existing pathology, particularly in the humerus where 77% of complete fractures had evidence of pre-existing stress fractures at necropsy.²  The stress and complete fracture of the humerus are the subject of this review. [...]