Racing performance in 75 Thoroughbreds after arthroscopic removal of Osteochondritis dissecans from the lateral femoral trochlear ridge before first race start in Korea (2015-2017).

This research study investigated the impact of arthroscopic surgery for removing Osteochondritis dissecans (OCD) from the lateral femoral trochlear ridge in racehorses before their first race. It found that while surgery delayed the first race start and resulted in fewer total races, it did not negatively affect overall performance, earnings, or retirement age. However, males consistently outperformed females, and certain factors, like having the surgery earlier or a larger lesion size, led to worse outcomes in females.

Study Design and Methodology

• The study is retrospective in nature and observes the medical and racing outcomes of 75 thoroughbred horses that underwent arthroscopic OCD removal at the Jeju Stud Farm Equine Hospital between 2015 and 2017.
• Several parameters were considered, including medical records, radiographic assessments, and race performance data.
• The study selected 257 control horses from the same dams as the surgical horses. This was done to compare the outcomes of the two groups.

Results and Findings

• Firstly, the surgical group had similar racehorse registration rates and first race start rates as the control group.
• However, the horses that underwent surgery had their first race start later and participated in fewer total races than the control group.
• Despite these differences, there was no significant variation in sales prices, career earnings, race points, or retirement age.
• The results also emphasised that neither the size of the OCD lesion nor the timing of the surgery had any significant impact on overall racing performance outcomes. The only exception was that horses that were operated on at an older age had a reduction in career duration.
• Sex-based analyses revealed that male horses consistently had longer career durations and better earnings compared to females.
• A closer look at subgroups revealed that females treated before 12 months of age and those with large lesions (40mm or more) tended to have poorer outcomes, including fewer starts and earlier retirement.

Conclusions

• Overall, the study concluded that arthroscopic surgery for stifle OCD in Thoroughbreds before their first race start doesn’t negatively affect overall race performance.
• While the timing of the surgery and the size of the lesion had minimal impact on the outcomes, the study suggests that the outcomes may be more strongly influenced by sex-related factors.