Managing Tendons: It Doesn't Have To Be A Stretch

Your horse will need time to heal, but some high-tech therapies can speed up the process.

Tendon swelling requires immediate veterinary assistance.Seeing your horse's head bob can make your head throb! High fever, a swollen eye, you name it - our horses really keep us on the edge of our seats. But one injury that gives us serious indigestion is the dreaded "soft tissue" injury. Soft-tissue injuries usually involve muscles, ligaments or tendons.

The bad news about tendon injuries is that they take a long time to heal and the road to recovery can be rough. The good news is that they can and do heal in most cases.

How tendons work. A tendon attaches muscle to bone. Elastic by nature, tendons are instrumental in movement and part of the lever system responsible for making joints bend (flex) and straighten (extend).

The most common tendons are the deep digital flexor tendon and the superficial digital flexor tendon. They run between the carpus ("knee") and fetlock down the back of the front legs, and between the hock and fetlock on the hind legs.

Tendon Injuries. The most common tendon injury is a tear. Also known as "tendinitis" or a "bowed tendon," tearing occurs when load bearing forces stretch a tendon beyond its physiologic range. Imagine a braided rope that is made up of hundreds of little fibers. If you use that rope to hang a grand piano off of a roof, you may see some of the rope fibers begin to snap. A similar phenomenon occurs when a horse over exerts itself and tears its tendon.

Tendon Healing. The three main stages of tendon healing are

1. Inflammation (heat, pain upon touch, swelling, lameness),

2. Repair or proliferation (regeneration of collagen tissue), and

3. Remodeling (which can be further divided into consolidation and maturation).

The inflammation and repair stages usually last a couple of months. However, depending upon owner compliance and the horse's disposition, it can take much longer or not happen at all.

This ultrasound shows the location of a tear in the superficial digital flexor tendon.

This ultrasound shows the location of a tear in the superficial digital flexor tendon.

Remodeling begins with consolidation, ideally lasting a couple of months. During this time, the newly formed tissue becomes stronger and the fibrils become aligned in the direction of mechanical stress.? In the final maturation stage, the tendon fibrils gain more strength by creating cross links between each other.

Tendon healing isn't a carriage ride through the park. it's more like a day on the New York stock exchange. It can go in the right direction for months and then plummet in a matter of minutes.

In many cases, horses get stuck in a phase of tendon healing and don't progress out of it, usually because they move around too much or the therapy itself isn't aggressive enough. In the worst cases, horses can be almost healed, and then something happens that sets them back, such as they get loose and have a field day. Incidents like these send an injured tendon back to square one.

First Response. If you're riding when it happens, You'll feel your horse pull up instantly lame. You'll hop off, hoping that he has a rock stuck in his shoe, but end up leading your limping horse back to the barn. it's clear which leg hurts, and after a bit of time passes, the tendon area will swell. Being able to identify a tendon injury early is monumental to your success in healing it, because what you do in the first 72 hours following the injury can set the tone for the entire course of the healing process.

If you take nothing else away from this article, please remember this:? Rest, Wrapping, Ice and Anti-Inflammatory Medications are absolute MUSTS during the inflammatory (early onset) stage of a tendon injury.

If your vet can't get to your horse the same day of the injury, be sure to talk with him or her about starting these first-response therapies.

Rest (aka "locking your horse in a stall") is critical to prevent further damage to the tendon. A horse must be prevented from exerting any more stress on a tendon by moving around on it.

Wrapping with a standing wrap (quilt+stable wrap) helps control the tendon swelling by "squeezing" it. As much as we like to think standing wraps provide support, they don't. However, they do a good job applying pressure to reduce swelling, which keeps blood and lymph vessels open and flowing.

Ice is vital to combating inflammation because it slows the metabolism in the damaged tissue, which reduces swelling, numbs the pain, and limits tissue damage due to release of harmful free radicals from the injured site. Unlike most animals, horses can have ice on an injured leg 24/7 and benefit from it.

In other animals, ice will initially cause blood vessels to constrict, however, the smooth muscles that line blood vessels usually can only stay contracted for so long before they fatigue and relax again (about 20 minutes max). After that, blood vessels open up again and the limb heats up, despite the ice being on it.

But not in horses! They have incredibly resilient smooth muscles lining the blood vessels in their legs, which means that their legs can benefit from ice therapy over long periods of time. Popular methods of icing include ice wraps or simply standing the horse with the injured leg in a bucket of ice water. We recommend using ice wraps because horses tolerate them well, and they are a bit safer and logistically easier than ice water buckets.

Anti-inflammatory medications make up the final first-response therapy.Inflamed tissues release hundreds of chemical agents that result in pain, swelling, heat, loss of function and sometimes redness. All of these processes can do more harm than good in most cases.

Provided that the horse isn't left to run free, giving anti-inflammatory medications such as bute or firocoxib (Equioxx, Previcox) immediately after a tendon injury will mitigate the damage by stopping the release of all of those nasty chemicals from the injury site.

But if he's not lame, why can't he run free? Pain's job is to protect the injured area. The horse's natural response is to limp and protect the area when he feels pain. This helps prevent further damage. Since the benefits of medications outweigh this one drawback, we have to do pain's job and limit the horse's activity. Actually, most horses are only lame for a few days after a tendon injury, but don't realize they?re injured, so we need to take it easy for them. The added weight of the rider alone can increase the damage significantly. Click here for information on topical anti-inflammatory, nutritional support and prevention of injuries.

Long-Term Therapy. As if the first 72 hours weren't bad enough, you now face months of long-term recovery, as the damaged tendon reconstructs itself and gains strength.

That's because tendons are basically made up of collagen, and collagen has virtually no blood supply. Since blood flow is responsible for clearing out damaged tissue and supplying nutrients and oxygen to rebuild new tissue, this puts tendons at a disadvantage.

And, when you consider that tendons are also partially responsible for making the horse stand, it becomes apparent that they really rarely ever get a break from their work. All this makes healing difficult but not impossible.

The high-tech therapies in our chart (click here) can be worth the seemingly exorbitant prices in terms of success rate and healing time. The decision on which to use must be made by your veterinarian.

Bottom Line. Tendons are incredibly resilient and elastic structures, but they aren't invincible. Preventing injuries by keeping your horse fit and riding judiciously is advisable. Intervening immediately with ice, rest, wraps and anti-inflammatories when a tendon injury first occurs is pivotal to the outcome of the healing process.

Article by Dr. Grant Miller, Contributing Veterinary Editor