Answered by, Terri Van Wambeke, DVM, Oregon City, OR
Courtesy of AAEP
Question: I have an off-the-track Thoroughbred that bowed a tendon in his last race. I would like to train him as a jumper after the bowed tendon has healed. What can I do to help the tendon heal properly? What should I use and how long should I give the tendon to heal?
Answer: This is a great question as tendon and ligament injuries are probably the most common injuries causing horses to need protracted lay-up and rehabilitation. My first recommendation would be to find a good equine ultrasonographer in your area and get an ultrasound examination of the injured tendon. This examination will serve as the baseline from which your veterinarian will determine how to proceed with rehabilitation and treatment. The length of rehabilitation, additional treatments and future prognosis will depend on the amount of damage to the tendon fibers and the way they are reorganizing and repairing.
Tendons are made up of bundles of fibrous connective tissue strands organized parallel to the leg. Imagine tendons like ropes made of individual fibers that form a very small bundle, then those bundles create another bundle, this goes on increasing in size until a very strong single bundle made of many bundles of fibers is created. Tendons connect muscles to bones and function much like a spring, storing energy during loading then releasing energy, like a spring recoiling, during unloading. During injury, damage occurs to either individual fibers or to bundles of fibers as they pull apart much like a rope begins to look frayed in the middle as it becomes overstrained. With a new injury, one will see pain, heat and swelling, the hallmark signs of inflammation, and varied degrees of lameness. In a chronic injury, lameness may or may not be present, and the tendon will be thickened without much pain or heat. Unfortunately, during repair of tendons and ligaments, the original organization and strength of the repaired fibers is often not a good as prior to the injury. This can leave the horse with a weak link at the site of injury. Careful rehabilitation, monitoring, and possible adjunct treatments can help increase the odds of full return to a successful career.
Initially, horses will need strict stall rest and oral anti-inflammatory treatment (such as phenylbutazone or flunixin meglumine) to minimize loading on the damaged tendon. Controlling the environment this way allows the body to create more organized repair tissue and minimizes adhesion formation. The worst thing for a damaged tendon is exposure to high loads during heavy exercise or exuberant play. Your veterinarian my also recommend icing, wrapping, topical anti-inflammatory agents and in-hand mobilization exercises to benefit range of motion of the leg. Generally, a few weeks after the injury has quieted down your veterinarian will recommend to begin hand-walking for a specified period each day. The length of time of hand walking will increase every few weeks depending on how your horse’s tendon is looking. Trot work usually begins 3-4 months after an injury and canter work around the 5-6 month range. Turnout is contraindicated until the horse is back to full work and ultrasound examinations are looking stable. It is important to make sure you have good footing for the horse during this period, not too deep, not uneven or hard, not slippery. If the horse becomes too fractious you may need to speak to your veterinarian about how to safely continue with rehabilitation. It takes about 6-9 months to get a horse back to full work after a tendon injury. Throughout this entire rehabilitation, it is critical that period ultrasound examinations be performed every 30-60 days, depending on the severity of the injury. Additional ultrasound examinations are warranted if there is any change in the appearance of the tendon or lameness. It is important that you palpate the leg daily to closely monitor any changes in pain, heat or swelling at the injury site. If you notice any changes you should contact your veterinarian immediately. I’m not sure how long it has been since your horses’ injury but there are biological therapies that are helpful to promote more organized tendon healing. These include the use of platelet-rich plasma (PRP) or stem cells. These therapies utilize the body’s own healing properties, with the help of science. Tissues are collected and incubated to increase the healing properties present, then they are injected, using ultrasound guidance, directly into the lesion(s) in the tendon. They help the body create a better healing environment and improve tendon organization and strength. You would need to consult with your veterinarian to determine if a biological would be of benefit to the horse. If so, these are a great adjunct to the traditional rest and rehabilitation program.
There are some great options out there to assist with rehabilitation. Underwater treadmill is a great tool for allowing the horse to begin heavier work without a huge increase in load on the tendon. These treadmills offer a wonderful way to maintain fitness and allow the horse to more safely burn off some energy in the process. Eurociser type horse walkers, that have individual moving stalls instead of head ties, are a good tool to gradually increase exercise time and type. They are safer for the handler when you have a horse that is becoming dangerous to walk in hand for lengthy periods of time or for beginning trot work if the horse is unsafe to ride.
Make sure that you keep the horse in healthy weight and avoid allowing him to become overweight, generally not an issue for an OTTB.
There are some shoeing changes that you can speak to your farrier and veterinarian about. You can place different shoes on the horse during rehabilitation that help support its specific injury. At a minimum makes sure that you remove any racing plates and have correct balanced shoeing.
Some modalities that I have had success with and regularly use in the treatment of tendon injuries include the use of extracorporeal shockwave therapy, therapeutic ultrasound and low level laser therapy (LLLT). You will need to work with your vet or a rehabilitation person for protocols should you decide to pursue any of these additional therapies.
Not to be overlooked is the role of proper nutrition. There is some anecdotal evidence in the human literature that amino acids (leucine, arginine and glutamine and for the horse Lysine), Vitamin C, copper, manganese and zinc may improve tendon healing. Make sure that the horse is on a balanced diet and speak with an equine nutritionist if you are unsure about how to accomplish this.