Racehorses with specific conformation are more likely to have certain musculoskeletal injuries, according to two recent studies completed at Colorado State University (CSU). At the 2003 American Association of Equine Practitioners' convention, C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, Dr.medvet (hc), Dipl. ACVS, director of CSU's Gail Holmes Equine Orthopaedic Research Center, presented results from the studies in which objective measuring was used to determine which limb conformations predispose the racing Thoroughbred and Quarter Horse to musculoskeletal injuries ranging from minor to catastrophic.

Genetics, racing surface, number of starts, age of the horse, pre-existing disease, conformation, and trauma have all been implicated as potential factors in the cause of racing and training injuries. Racing surfaces, number of starts, and trauma have all been examined independently and objectively, but most reported relationships between injury and conformation are based on practical experience of the veterinarian and logical hypotheses. Tina Anderson (who worked on this project for her PhD) and McIlwraith developed a novel way to objectively determine what to look for structurally in racehorses that might predispose them to injury.

In the first portion of the study, 115 3-year-old Thoroughbreds (all bred and raised at one farm) were photographed from the front, rear, and side with special markers placed in specific places. All photographs included a ruler to ensure correct scale. McIlwraith and others measured lengths and angles of conformation with a software program, and they used an objective method of grading the degree of offset knees (bench knees).

Next, McIlwraith and colleagues recorded clinical observations, clinical conditions (including diagnoses from the radiographs), and made subjective evaluations of limb rotation in each horse. These parameters were collected every two months from birth to cessation of the study