Page 72 - November 2020

EQUINE HEALTH
recommended for rehab in tendon repair. The important thing is safety first—for the rider, the handler, and the horse. It doesn’t do anyone any good if the rider gets bucked off and the horse is running around in the pen as fast as it can,” he says.
It is important, however, to keep the horse in some type of exercise, whether hand walk- ing or tack walking a couple times a day—get- ting the horse outside of the stall multiple times. This helps the horse mentally as well
as physically and keeps the muscles stronger. “If it’s a novel experience for the horse to go outside the stall, the horse will go crazy, so you need to utilize some form of controlled exercise, and a way to monitor the rehabilita- tion program,” says Cassells.
“Some heal faster than others, but typically tendon injuries take six to eight months, if
not longer, to get back to a full level of work. Tendons take longer than bones to heal, and the rule of thumb is that it takes one month per letter, i.e. bone takes four months to heal, tendons take six months and ligaments eight months. It’s an easy way to remember it, and ligaments are the slowest to heal because there is less blood supply to a ligament. The tendon at least has muscle fibers with blood in them, at that end. It varies, of course, depending on where the injury is. If it’s up near the muscle,
as stem cells or PRP,” says Cassells. “If there’s scar tissue and the lesion is old, I am a big fan of shockwave therapy to help break up the scar tissue and stimulate blood flow. Shockwave therapy can be very nice to use because it is non-invasive, very safe, and relatively inex- pensive compared to some other treatments. It can also be done multiple times throughout a horse’s career.”
Laser therapy has also been shown to be ef- fective, but Cassells feels that the best thing to use in a horse with a fresh injury is ice. “Treat- ing a fresh injury with cold will slow down the inflammation and swelling. Using cold therapy (ice or ice boots) for 48 to 72 hours after an injury and then applying bandages with a poultice to try to reduce inflammation can be very effective. The more you can reduce the inflammation in a fresh injury, the better and faster it will heal,” he explains.
BOWED TENDON
One of the most common types of tendon injury is bowed tendon, caused by excessive strain. There are two tendons located behind the cannon bone--the deep digital flexor tendon and the superficial digital flexor ten- don, one behind the other. These tendons are covered with a sheath and lubricated with sy- novial fluid. If the tendons and/or sheath and/
Ultrasound is a useful tool to monitor lesions to see the healing process or to see if any new ones have formed.
or horses too heavy for their tendon structure. The horse may bow a tendon while running hard, galloping uphill, turning quickly, buck- ing, or suddenly accelerating to full speed. A severe blow to the tendon, such as the horse striking it with another foot, may also create enough damage to result in a bow.
BENEFITS OF ULTRASOUND
it might heal faster than if it’s in the middle of the tendon where there is no blood supply.”
The treatment for a tendon injury is based on the lesion—whether it is a large core lesion or just a strain with mild thickening or if there is a lot of thickening. “For a large lesion, I gen- erally prefer to use regenerative therapy such
or attachments are injured or torn, swelling is caused by hemorrhage and inflammation. The swollen area is hot and painful, and the horse is quite lame.
If the superficial digital flexor tendon is in- jured and not properly treated, it can become permanently thickened due to creation of
scar tissue within the tendon and surround- ing tissues/tendon sheath, and the adhesions that form--often binding the tendons together and/or to the sheath. This creates a bowed appearance in the otherwise straight tendon. The bow can be high (just below the knee or hock), middle, or low (just above the fetlock joint). The middle area is most often injured, where the tendon has the smallest diameter. Severe injury may involve the whole length of the tendon.
Bowed tendon injuries are common in front legs of racehorses and only rarely occur in hind legs. Common causes are inadequate fitness conditioning and muscle fatigue at the end of
a long race. When the muscles become tired, they cease to contract in perfect synchroniza- tion and then some of the strain, that is usually taken up by the more elastic muscles, falls upon the less elastic tendons.
Horses that seem most likely to bow a tendon during strenuous exertion are horses with long, weak pasterns, long toes, horses that are not in condition for the work, horses in rigorous training or doing strenuous exertion,
Dr. Mark Cassells has been practicing for more than 20 years and says one of the best things that has happened in those years is improvement in our ability to catch tendon injuries early with ultrasound.
“The ultrasound technology and equipment has gotten better every year, so we are able to pick up subtle lesions earlier than we could before. We can catch them before there is so much damage,” he says.
“The other benefit is that we can monitor these lesions with ultrasound after treatment to see how they are doing. The treatment might be regenerative therapy with stem cells, PRP, etc. We can monitor that lesion with better accuracy and see how it’s healing much better than we could 10 or 15 years ago,” Cas- sells explains.
Another reason he likes to use ultrasound is that when a horse is put into a rehabilitation pro- gram and you start increasing the workload, the tendon can be readily monitored. “Even though the horse may be performing well and is acting okay, we still need to see how the structure is handling the work. Is the tendon holding up
or are we starting to see more signs of lesions?” Ultrasound is one way to make sure that the horse is not being pushed too hard. This just gives a person more confidence about stepping up to the next level. You are always walking a fine line, trying to strengthen the structure as it heals rather than tearing it down.
Shockwave therapy can be useful in treating many things, such as suspensory ligament injuries, acute tendon injuries and arthritis of the stifle and pastern. This type of therapy is a great way to break up scar tissue and stimulate blood flow.
70 SPEEDHORSE November 2020