Moderate to severe superficial digital flexor (SDF) tendon lesions in Thoroughbred racehorses have typically carried a poor prognosis for a return to racing and a lengthy rehabilitation process for horses that do return. But a team of veterinarians recently took a closer look at a procedure that could help improve the outcome for Thoroughbreds with such injuries: superior check ligament desmotomy surgery.

The surgery—which involves cutting the accessory (superior check) ligament of the SDF tendon—is based on the premise that the ligament, once healed, is slightly longer than it was pre-cutting, resulting in a partial transfer of strain off the SDF tendon and onto other limb structures, particularly the suspensory ligament.

“It gives the horse a little more tendon to work with,” explained study author and surgeon Larry Bramlage, DVM, MS, Dipl. ACVS, of Rood & Riddle Equine Hospital, in Lexington, Kentucky. “In addition, it takes the tension off the tendon during the healing period, reducing fibrosis (scarring) during healing.”

Bramlage and Alaine Hu, DVM, presently of Kirkwood Animal Hospital in Campbell, California, looked at 332 Thoroughbred racehorses that underwent the surgical procedure at Rood & Riddle. Using the horses’ race records to assess outcome, the team sought to determine how many of the treated horses returned to racing, how long it took them to return, and how many race starts they made post-surgery