Risk of tendon reinjury?

Q:What is the risk of a horse reinjuring a tendon after it has healed? My horse was laid up for nearly a year with a badly bowed tendon. He was treated and rehabbed carefully, and we are returning to the show ring, but I am paranoid about reinjury. Are there any statistics that can put my mind at ease? Are there specific things I should do or avoid to protect that tendon?

Name withheld by request

A:Your anxiety over reinjury is understandable, particularly after you’ve spent so much time helping your horse recover.

Although you don’t mention your horse’s sport or activity, the statistics in racehorses are fairly representative: Around 60 to 70 percent of those with tendon injuries who undergo routine rehabilitation reinjure the leg in the first two to three years after resuming work. Those statistics may not seem very encouraging, but keep in mind that variables related to your horse’s specific situation will influence his likelihood of reinjury.

I’m not sure what sort of therapy your horse received, but research has shown that treatment with cultureexpanded stem cells has substantially lower reinjury rates. In this protocol, stem cells are taken from bone marrow and grown in a laboratory. The resulting cells are then injected back into the injury site. In a study of racehorses with tendon injuries, the reinjury rates dropped to around 20 percent---so were three times better---in horses who underwent this procedure than in those who were simply rested and given conventional treatments. Thus, I often recommend this treatment option for horses with

moderate to severe tendon injuries.

As for protecting the tendon at this point, a gradual and consistent level of work is key. You’ve shown great patience taking a full year to rehabilitate your horse, and I would urge you to continue with that mindset and restraint. Your horse needs regular exercise---fit horses are less prone to injury and reinjury than are those ridden only sporadically---but be careful to increase the speed, intensity and duration of work incrementally to allow the healed tendon to adapt to the new demands. David Frisbie, DVM, PhD, Dipl.

ACVS, ACVS-MR Colorado State University Fort Collins, Colorado