Use of quantitative ultrasonography for noninvasive surveillance of the third metacarpal bone in racing and training Thoroughbreds.

The research investigates the link between the speed of sound in the third metacarpal bone of racing Thoroughbreds and their accumulated workload, and how this connection is affected by bone failure. The study suggests that as the workload increases, there’s a consistent pattern in how the speed of sound progresses in the bone. With improved precision in ultrasonography devices, it may be possible to use this measure to identify horses at risk of bone failure.

Objective and Methodology

• The purpose of this study is to use quantitative ultrasonography to explore the relationship between the speed of sound (SOS) in the third metacarpal bone (MCIII) of racing Thoroughbreds and their workload accumulation, and how the presence of MCIII failure impacts this association.
• The study involves sixty-two 2- and 3-year-old Thoroughbreds in racing condition.
• The total workload (referred to as CWItotal) and independent workloads pertaining to different gaits (trot (CWI(trot)), gallop (CWI(gallop)), and race (CWI(race)) were calculated using a Cumulative Work Index (CWI).
• The researchers monitored the SOS in the horses during the 2007 racing season and then compared these findings with the CWIs using regression analysis.
• Covariates in the study model included sex, age, limb, and MCIII failure.

Results of the Study

• It was discovered that SOS held a significant association with CWI(total) at 8 of the evaluated sites and with the independent CWIs of the various gaits at all 9 sites.
• When the horses displayed clinical signs of metacarpal bone failure, the SOS progression in their MCIIIs differed significantly from those without bone failure, which was observed in one site when considering CWI(total), and in five sites for the independent CWIs pertaining to various gaits.

Conclusions and Clinical Relevance

• The study concluded that the SOS in the MCIII of racing Thoroughbreds followed a consistent pattern as their workload increased.
• Given the development of more precise quantitative ultrasonography devices, SOS, adjusted to account for the amount of activity, could potentially be used to identify horses that are at high risk of bone failure.