Reasons for performing the study: ReGeneraTing Agents (RGTA) are nano-biodegradable-polysaccharides engineered to mimic heparan sulphates and have been shown to stimulate tissue repair and healing in several animal models of injury and in human medicine. A preliminary uncontrolled study on tendon healing in horses using injection of a dedicated RGTA (named Equitend®) showed encouraging results.

Objectives: to evaluate the effect of a single intralesional injection of Equitend® versus placebo on the healing of acute superficial digital flexor tendonitis in racing French Standardbred trotters (ST).

Study Design: randomised, double-blind, controlled, multicentric clinical study.

Methods: Twenty-two ST were randomly assigned to receive Equitend® or saline intralesional injection under ultrasonographic guidance. Horses were followed over 4 months with clinical and ultrasonographic evaluations (day 0, months 1, 2, 4), and their performance criteria were obtained over 2 years after treatment. Reinjury rate, mean earnings per race, number of starts and victories before and after lesion were studied.

Results: A significant decrease of cross sectional area over time was found in the treatment group compared with the placebo group. The Equitend® group presented a higher number of races (trend) and a significant higher number of victories after treatment than in the placebo group. Reinjury rate was higher in the control group (41.7%) than in the Equitend® group (15.5%), even though it was not statistically significant.

Conclusions – The results of this study demonstrate a long-term beneficial effect of intralesional injection of Equitend® for the treatment of superficial digital flexor tendonitis on racing ST.