Does your horse -- or a horse you're considering buying off the track --have an old "bowed" tendon? If so, you're probably asking yourself, "Will he have soundness problems in the future? Will he be able to do the job I want him to do? What sort of special care does he need?"
Of all the horses that bow tendons, a small percentage are never reliably sound again. But a large percentage can, once the bow heals, go back and tackle any discipline other than racing or upper-level eventing. Many go on to successful careers in the show ring -- some even as grand prix jumpers. And plenty of show hunters with old bows jump 3-foot 6-inch fences for years without a problem.
How Bad Is It?
To evaluate an old bowed tendon, answer the following questions:
1. How recently was the tendon bowed? Bowed tendons change in shape and consistency as they heal. If you don't know enough of your horse's history to answer the question, ask your veterinarian to help you estimate how old the injury is. If it's still in the acute phase, it will need rest and care. If the horse has had six months to a year to recover but hasn't been in regular work since the injury, you'll need to follow a very careful legging-up process. Unless you have a great deal of experience in this area, I don't recommend buying a horse with a bowed tendon unless the bow is more than a year old.
2. Has the tendon been recently examined by an experienced ultrasonographer? Although a clinical exam (judging the injury by how it looks and how it feels to the touch) is an important tool, proper diagnosis of a bowed tendon cannot be done accurately by palpation (squeezing with the fingers) alone. Ultrasound technology has helped us immensely both in avoiding too-early returns to work for horses that appear sound but haven't actually finished healing, and in prolonging down time unnecessarily for horses that have.
But not all veterinarians are comfortable analyzing tendon ultrasounds. (Many vets' ultrasound equipment is the low-resolution type designed for reproductive checks -- less effective in imaging tendon injuries than the more sophisticated technology available for tendon diagnosis.) If your veterinarian isn't known for doing a lot of lameness and ultrasound work, ask him if he's comfortable in this area or if he thinks you ought to consult a specialist. (A more subtle way to put this is to ask, "How does this case compare to cases you've seen before? Is this an unusual ultrasound finding, in your experience?") He may suggest you consult a large referral practice, a university clinic, or a solo practitioner kown for lameness expertise. (The American Association of Equine Practitioners is a good resource for specialists; to find a member veterinarian in your area, call 1-800-438-2386 or visit http://www.getadvm.com.)
3. What was the extent of the damage? Along with expertly analyzed ultrasonography, the shape and location of a tendon injury can tell you a great deal about the extent of permanent damage -- and, therefore, the probability of re-injury. For example, a dramatically curved "banana" bow was most likely a serious injury initially and may not have had adequate post-injury care, so that an excessive amount of scarring has thickened and shortened the tendon (which contracted as it healed). Horses with such extreme bows are more likely to have trouble staying sound than those with minor contour changes. To be safe, I'd recommend not buying a horse with a thick, disfiguring bow.
I'd also avoid buying a horse whose leg has changed conformationally as a result of the bow. For instance, massive scarring can cause the tendon to contract to the point where the injured leg looks more upright in the pastern than its mate, or the knee seems to be buckling forward even when the horse is standing still. Although he may be sound at the moment, this permanent damage may limit his athletic ability and cause recurrent lameness.
Bowed tendons most prone to secondary problems usually occur in the middle or lower third of the tendon. The lower injuries, especially, tend to interfere with the annular ligament, which surrounds the superficial flexor tendon in a canal behind the fetlock joint.
Even where such injuries are mild at first, the inflammation may return when the horse goes back into work, causing recurring injuries. We often succeed in repairing this problem by surgically cutting the annular ligament. The ligament grows back, but in a way that creates more room in the canal, relieving the pressure and allowing more ease of movement.
4. Is there ever any change in the size or contour of the affected leg? Is the horse ever lame? Is there any sensitivity to palpation of the tendon? If you answer "yes" to any of these questions, the tendon injury may still be active; it may heal with further rest and care, or (worst-case scenario) it may be problematic for the rest of the horse's life. Consult your veterinarian to determine which kind of case you're dealing with.
Excerpted from "The Lowdown on 'Bowed' Tendons" in the January 2001 issue of Practical Horseman magazine.
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