Retrospective study of outcome following desmotomy of the accessory ligament of the deep digital flexor tendon for type 1 flexural deformity in Thoroughbreds.

This research investigates the long-term outcomes of Thoroughbred horses that underwent a specific surgical procedure known as desmotomy of the accessory ligament of the deep digital flexor tendon (DAL-DDFT), which is used to treat a type of limb deformity in horses. The study found that horses treated with this procedure were less likely to race compared to their siblings, but for those who did race, their performance and earnings were not significantly different.

Understanding the Research

• The research is a retrospective matched cohort study which examines medical records over a 17 year period of Thoroughbred horses that underwent a specific operation, the desmotomy of the accessory ligament of the deep digital flexor tendon (DAL-DDFT). This operation is used to treat type 1 flexural deformity of the distal interphalangeal joint (DIPJ), a type of limb deformity in horses.
• The purpose of the study was to determine the long-term outcome for these horses, in particular their performance in horse racing compared to their maternal siblings that did not undergo the operation.

Main Findings

• 46 cases of DAL-DDFT were reviewed in the study. The average age of the horses at surgery was 151 days.
• The study found that 48% of the horses that underwent the surgery raced, compared to 77% of the control group, which consisted of 90 horses who were siblings but did not undergo the operation.
• However, for those horses that did race, there were no significant differences in race performance or earnings when compared to the control group. Factors analysed included time to first race, total number of starts, and prize money per race.
• The age of the horse at the time of surgery had no impact on whether it would eventually race or not. This suggests that the timing of the operation does not influence the long-term outcome for the horse’s racing career.

Conclusions

• The study concluded that Thoroughbred horses undergoing DAL-DDFT for type 1 flexural deformity of the DIPJ are less likely to race compared to their siblings. However, for those that do race, their results and earnings are on par with the control group.
• Furthermore, there is no evidence to suggest that age at the time of surgery influences the likelihood of the horses participating in racing. This implies that the decision regarding the timing of the operation can potentially be more flexible, as it does not seem to impact the horse’s future racing career.