Diagnostic imaging to reduce Thoroughbred racing fatality

Summary

This study aims to investigate the imaging appearance of subclinical and/or clinical disease in the fetlocks of southeast Queensland Thoroughbred racing fatalities. We will compare the utility of advanced imaging modalities for the identification of pathologies within the fetlock region with particular focus on the identification of possible risk factors or prodromal changes indicative of fracture. An in vitro study is planned, using limbs from Thoroughbreds that are euthanised during training or racing. All four limbs of each horse will undergo a complete radiographic examination, lowfield magnetic resonance imaging (MRI) and noncontrast and contrast computed tomography (CT) examination of the fetlock region followed by gross pathology and targeted histopathology. Any abnormalities identified will be compared between imaging modalities and correlated with the results of pathology examination. Horses will be divided into three groups for further comparison according to reason for death – fracture in fetlock region, fracture in another region, no fracture (e.g. presumed cardiovascular fatality). The fractured limb and nonfractured contralateral limbs will be compared within any one horse and between horses. This study will result in better understanding of the occurrence and imaging appearance of clinical and subclinical disease in the fetlock region of our racehorse population, leading to earlier detection and improved formulation of recommendations for treatment and management. Screening of atrisk horses could potentially reduce the number of horses that progress to breakdown or injury related to the fetlock region while racing or training.

Program

Thoroughbred Horses

Research Organisation

The University of Queensland

Objective Summary

Our objectives relate directly to the 6th RD&E objective (Reduce injury and breakdown of horses in work and training). Our first objective is to determine the imaging appearance of subclinical and clinical pathology in the fetlock region of racing Thoroughbred fatalities at southeast Queensland racetracks. Our second objective is to compare the ability of radiography, lowfield standing MRI and CT to diagnose and characterise these pathologies. By comparing relevant pathological findings and their appearance/visibility with the various different imaging modalities, we will gain further knowledge about the relative strengths and weaknesses of each modality specifically for Thoroughbred racehorses in training. Our third objective is to identify any trends or common imaging findings in these cases which could potentially serve as markers in our training and racing population. With improved knowledge of the occurrence and appearance of injuries in horses that suffer catastrophic fetlock fractures, we hope to develop strategies for earlier identification of atrisk horses, appropriate treatment and educated management decisions.