Risk factors for superficial digital flexor tendinopathy in Thoroughbred racehorses in South Korea (2015-2019).

Background: Superficial digital flexor (SDF) tendinopathy is one of the most common musculoskeletal diseases in Thoroughbreds and a major cause of retirement from racing among racehorses in South Korea. However, there are no previous epidemiological studies on SDF tendinopathy-related risk factors for racehorses in South Korea. The interventions derived from such a study could reduce the occurrence of SDF tendinopathy and, therefore, extend horses' racing careers.

Objectives: To identify the risk factors associated with SDF tendinopathy for Thoroughbreds in South Korea.

Study design: Retrospective case-control study (2015-2019).

Methods: A total of 101 Thoroughbreds that were diagnosed with SDF tendinopathy following a recorded fast-exercise (training gallop, trial racing, racing) between 2015 and 2019 were included in the study. Additionally, 304 healthy Thoroughbreds (319 events) with at least one recorded fast-exercise between 2015 and 2019 were also included as controls. Multivariable logistic regression was used to identify risk factors for SDF tendinopathy.

Results: SDF tendinopathy was significantly more likely to be diagnosed after racing or trial racing than after galloping. Horses with lower grades (6, ungraded) based on racing performance were associated with a higher risk of SDFT injuries. An increased risk of SDFT injury was observed with fewer gallop training days in the previous 60 days to the last fast-exercise, more canter training days in the previous 180 days, or having a period of no fast-exercise for over 90 days in the year prior to the event.

Main limitations: Information on the distance and speed of gallop training was not available.

Conclusions: The implementation of risk profiling and other preventive measures for horses with fewer gallop training days before racing could help minimise the number of horses sustaining SDF tendinopathy.