Surgical Success for Horses with Tendon Injuries

Horses with moderate to severe injury to the superficial digital flexor tendon (SDFT) can return to high-performance careers, according to new research, though success requires a combination of surgery, bone marrow therapy, and a carefully designed rehabilitation program.

Considering how common SDFT injuries occur, this is welcome news. Horses managed with traditional approaches to SDFT injuries, relying predominantly on rehabilitation, are prone to reinjury, contributing to additional lost training days and attrition.

“Horses with tendon injuries are often laid up for many months, sometimes a year or more. Therefore, finding reliable and effective ways of treating this common injury will allow injured horses to continue competing both as racehorses and sport horses,” explained Catherine Whitehouse, M.S., a Kentucky Equine Research nutritionist.

Since first used as an intralesional therapy in the suspensory ligament, bone marrow injections for tendon and ligament injuries have become routine. To help devise the best treatment plans for SDFT injuries involving bone marrow injections, Australian researchers recently reviewed the medical and racing records of 114 horses. Thirty-seven of those horses were sound, healthy racehorses. Thirty-eight were diagnosed with moderate injury to the SDFT treated conservatively (i.e., a structured rehabilitation program), and the remaining 39 horses were treated surgically.

The surgical treatment involved a combination of check ligament desmotomy (a routine surgical procedure that reduces tension on the SDFT) and bone marrow injected directly into the injured region of the tendon, typically guided by ultrasound. The bone marrow was harvested from the patient’s sternum.

“Overall, the researchers concluded that the surgically treated horses had a favorable outcome compared to the conservatively managed horses, all of which had naturally occurring flexor tendonitis,” Whitehouse explained.

That conclusion was reached by comparing five key performance indicators: return to racing, number of starts, days to first start after injury, earnings per period of time, and earnings per start.

More specifically, the data showed that:

• Horses treated surgically were 4.7 times more likely to return to racing than conservatively managed horses; and
• Surgically treated horses returned to racing sooner than horses treated conservatively.

 “Researchers noted that the horses in the surgically treated group were diagnosed with moderate to severe acute tendonitis, whereas the conservatively managed horses were only diagnosed with moderate lesions. This means that the conservative group already had a better prognosis than the surgical group,” said Whitehouse.

Even with aggressive treatment, however, success is not guaranteed. As described in the study, 29% of the horses treated surgically re-injured the same tendon and 9% injured the tendon on the adjacent limb.

“To help support the skeletal systems of horses with tendon injuries subjected to sudden layups, we recommend offering Triacton, a triple-action bone and digestive health supplement that helps maintain bone density. The trace minerals and vitamins are beneficial for the recovery of soft tissue injuries,” advised Whitehouse.

 *Murphy, D.J., V. Kö-Peternelj, and J. Wafula Aleri. Intralesional bone marrow and superior check desmotomy is superior to conservative treatment of equine superficial digital flexor tendonitis. Equine Veterinary Journal 13553.