Written by: Keith McCalmont

First used on humans, shock wave therapy is controversial but proving to be a popular treatment for tendon, ligament and many other injuries in racehorses

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Injuries are par for the course in any high performance sport, so it’s no shock that thoroughbred race horses will sometimes need a tune up. However, what might come as a surprise is that one of the most effective treatments is shock wave therapy.

“I find if you are treating an acute flare up such as a crack in a splint bone it works really well to promote healing. For tendon injuries it works really well. It is used for all kinds of treatment,” advises Judith Koenig DVM, Associate Professor of Large Animal Surgery at the Ontario Veterinary College located at the University of Guelph.

Shock waves are high-pressure, low frequency sound waves, applied to the specific injured area. As the shock waves meet tissue interfaces of varying densities, the kinetic energy within the shock waves is released and combines with the tissue.

“It is routinely used for both soft tissue injuries as well as orthopedic injuries and it seems to work by increasing growth factors and to promote healing of tissue,” explains Dr. Koenig. “It has been proven scientifically to work by increasing growth factor levels in tendon healing and for bone, it has been scientifically proven to increase the number of cells that generate bone.”

It is a treatment that was first used to assist human beings with kidney stones, allowing the breaking up of the stones without the need for invasive surgery. The process is also a common treatment for heel spurs, tendon issues and ‘tennis elbow’. Although there are many equine orthopedic conditions similar to these human ailments that mimic soft tissue injuries and trauma to the interface of ligaments with bone, there are varying opinions on the use and scope of shock wave treatment.

“I just came back from a symposium on shock wave therapy, and to give you an idea how controversial it is, there are people who use shock wave for crooked legs in foals. They put the shock wave on one side of the joint and say that ‘you have to put it here,” starts Dr. Koenig. “However, then there will be another group from another continent that put the shock wave on the other side of the joint and both groups say they have success. There are some things that are not investigated.”

Despite the conflicting reports, there are numerous real life success stories in the thoroughbred racing industry. Woodbine-based trainer John LeBlanc is a staunch proponent of shock wave treatment.

“I’ve used it quite a bit. I’m a fan of it and I’ve had some very good success,” states LeBlanc. “There are different shock wave machines that are available. Some are wide spectrum shock wave and then there’s the very narrow beam type of shock wave.”

LeBlanc notes Toronto Equine Hospital, led by Daryl Bonder, DVM, as a top clinic that used shock wave therapy to assist his first stakes winner, Hopeful Moment, back to the winner’s circle.

“Dr. Bonder had a very big machine at his clinic and he was able to pinpoint a spot and isolate a very specific area which was fabulous for injuries where a horse (Hopeful Moment) had torn his ligament away from the back of his knee and actually took a piece of bone with it,” explains LeBlanc. “Dr. Bonder shock waved that area and it healed it well enough for the horse to come back and make over $200,000 and win a stake race. He was my first stakes winner and he had absolutely no re-occurrence with that injury further on in his racing career.”

Hopeful Moment, winner of the 2001 Shepperton Stakes at Woodbine, is now enjoying his retirement at LeBlanc’s farm in Rosemont, Ontario. The veteran conditioner has been sending out winners since 1992 and has enjoyed multiple successes with the treatment.

“I’ve used it on shins, tendons, ligaments and I even used it on a horse who had a collapsed jugular vein,” says LeBlanc. “The vet came in to do some shock wave and we did an experiment to see if we can rejuvenate it. She shock waved the area and it was back to normal within a couple days. I think it’s a great machine used in the right manner.”

LeBlanc, a caring horseman and longtime supporter of LongRun Thoroughbred Retirement Foundation, thinks of the horse first and appreciates that the treatment is no miracle cure.

“The healing powers (of shock wave therapy), if you allow the body time to do the healing, are exceptional,” starts LeBlanc, and offers the following scenario. “If a horse bucks it shin, it’s body will lay down the calcium. Now, it may not lay down as much calcium to heal that area as quickly as when we shock wave it. When you shock wave, the body says ‘we really have to heal this’. It speeds up the body’s response. At the same time, you need to let the body do the healing as well. That’s where some people might get confused with this being a wonder tool or drug. It’s not a one-time use and you’re good. You still need to give it time to heal.”

Owners expecting a quick fix for their injured horses must be forewarned what ORC rule 15.37 provides:

The use of Extracorporeal Shock Wave Therapy or Radial Pulse Wave Therapy shall not be permitted on any race horse unless the following conditions are met:

(a) the treatment took place a minimum of 4 days (96 hours) prior to competing in a race;

(b) the treatment using the Extracorporeal Shock Wave Therapy or Radial Pulse Wave Therapy machine was conducted by a veterinarian licensed by the Commission as a veterinarian;

(c) any treatment received while on the grounds of the Association was through the use of an Extracorporeal Shock Wave Therapy or Radial Pulse Wave Therapy machine owned and operated by a veterinarian licensed by the Commission; and a record of the treatment, including the date and time, is maintained as part of the record of the horse.

The rule is written sternly to prevent unscrupulous types from using the treatment to numb an injured area to give the horse the appearance of being healthy.

“If it is used properly it is a great tool,” states Dr. Koenig. “I think it has a lot of potential to promote healing but unfortunately if it is used inappropriately you can decrease pain if applied over nerves, for example. It can be used to make a horse look sound even though it is not, just by decreasing pain, because it has an effect on the nerve conduction.”

An unsound horse on the racetrack is a danger to both horse and rider and the implication is not lost on those that govern the sport. In May of 2010, the Racing Medication and Testing Consortium (RMTC) – which consists of 25 racing industry stakeholders and organizations that represent Thoroughbred, Standardbred, American Quarter Horse and Arabian racing – committed $450,000 to fund Dr. Heather DiMaio Knych and Dr. Mary Robinson for their post-doctoral research fellowship program. This funding supports the RMTC Drug Testing Initiatives Task Force, established in 2008 to improve drug testing and racing integrity.

“This is another major step by the RMTC to implement the recommendations that I made at The Jockey Club Round Table Conference in August 2008 toward an improved drug testing program for U.S. racing,” advised RMTC Vice Chairman Alan Foreman in a recent press release. “We are beginning the process of developing our next generation of scientific experts in the equine industry who will be working with us on emerging medication problems. We hope the research of Drs. DiMaio Knych and Robinson will help us better regulate corticosteroids and shock wave therapy, which will be a major step in protecting the health and welfare of our equine athletes and the interests of the wagering public.”

Although there is much left to be written regarding the most effective uses of shock wave therapy, it is encouraging that the industry continues to support the studies of experts here and abroad.

A recent paper published in the American Journal of Veterinary Research by Andressa Silveira, DVM, under the supervision of Dr. Koenig, studied the effects of unfocused extracorporeal shock wave therapy (ESWT) on healing of wounds of the distal portion of the forelimb in horses.

In the study, five superficial wounds were created on the limbs of six horses and treated with 625 shock wave pulses from an unfocused electro-hydraulic shock wave generator. For comparison, the treatment was randomly assigned with control wounds receiving a sham treatment. The study concluded that ESWT did not accelerate the healing but that the treated wounds demonstrated less proud flesh and appeared healthier than the control specimens.

“We have shown a better quality of healing and less inflammation in the wound,” states Dr. Koenig who is already working on a second paper on the subject. “The next study is looking at the different level of growth factors and how shock wave affects wound healing. It seems that this treatment does have an effect and it is not a placebo.”

For now, the study continues with the hope that the dramatic improvements to equine health continue to shock the industry – in a good way