Gauging Bone Mineral Density to Predict Injuries in Thoroughbred Racehorses

Fracture of the proximal sesamoid bones located in the fetlocks is a leading cause of injury in racehorses. The ability to pinpoint which horses are at risk of sesamoid bone fracture would improve racehorse welfare, yet current imaging techniques are incapable of predicting injury.

In a recent study designed to predict sesamoid bone fracture, Cornell University researchers measured bone mineral density using dual-energy X-ray absorptiometry (DXA).^* DXA is the tool of choice for measuring bone mineral density in humans, a population in which low bone mineral density often leads to fracture.

In this study, 14 limbs from horses that suffered unilateral sesamoid fracture and 15 control horses without evidence of fetlock injury were included. All limbs underwent DXA as well as computed tomography and Raman spectroscopy to assess overall fetlock health. Any pathologies were noted.

“Contrary to the researchers’ hypothesis, there was no association between bone mineral density and sesamoid fracture in this study population,” explained Kathleen Crandell, Ph.D., of Kentucky Equine Research.

Bone mineral density was, however, higher in horses with more high-speed furlongs in their training history. In addition, the other imaging techniques revealed that joint abnormalities, such as palmar osteochondral disease and third metacarpal sclerosis, were also greater in horses with more high-speed furlongs.

The researchers wrote, “Whole bone mineral properties or fetlock joint pathologies are not alone sufficient for identifying horses at risk of proximal sesamoid bone fracture.”

“Bone mineral density and joint abnormalities increased with exercise but were not different between the fracture and control groups,” Crandell summarized.

Alternate means of assessing fetlock health are therefore required to predict fetlock and sesamoid bone breakdown and fracture. Instead of bone mineral density measured by DXA, the research team suggested combining positron emission tomography (PET) with computed tomography.

“Identifying parameters correlated with proximal sesamoid bone fracture using both modalities could improve the accuracy of identification of horses at risk for fracture,” concluded the researchers.

Supporting bone health is important to Kentucky Equine Research, and the company’s research has resulted in the development of several bone supplements, including Triacton.

According to Crandell, “Triacton features a novel source of calcium shown to be more highly digestible than other forms of the mineral. This product also contains an array of other bone-building nutrients, including magnesium, boron, silicon, iodine, zinc, and manganese. We also included vitamins A, C, D, and K, which are important for bone health and research has shown the supplement produced significantly increased bone mineral density during training.”

This combination of vitamins and minerals helps increase bone density in young, growing horses and athletic horses, especially those involved in intense training such as racehorses or during layups or box rest when bone can lose mineral density.

^*Noordwijk, K.J., L. Chen, B.D. Ruspi, S. Schurer, B. Papa, D. Fasanello, S.P McDonough, S.E. Palmer, I.R. Porter, P.S. Basran, E. Donnelly, and H.L. Reesink. 2023. Metacarpophalangeal joint pathology and bone mineral density increase with exercise but not with incidence of proximal sesamoid bone fracture in Thoroughbred racehorses. Animals (Basel) 13(5):827.