When buying a horse, particularly a sport horse, you’ll take a good long look at his overall conformation. You’ll hold an ideal image in your head of the type of horse needed for your chosen discipline and compare him to that ideal. You’ll make a note of any faults that may interfere with his future performance. A horse with a nice sloping shoulder, moderately sloped pasterns, and straight legs viewed from the front is, of course, desirable for any sport. But, even a horse with good conformation can develop problem joints. Perhaps at no other time in history have we had so many new treatment options on the horizon. In this month’s “Horseman’s Corner,” we bring you several exciting new therapies and diagnostic tools. 

Joint Modeling

The Orthopaedic Research Center of Colorado State University is studying a new diagnostic technique called joint modeling. The idea is to create a computer model (a mathematical representation) of all the forces on the tendons, bones, cartilage, and ligaments of the joint. Through the use of CT, MRI, and visual examination, orthopaedic specialists may eventually be able to predict the potential for injury based on the results of joint modeling of the individual horse. Researchers admit it is all very “futuristic,” but the work is promising.

Extracorporeal Shock Wave Therapy

Extracorporeal Shock Wave Therapy (ESWT) is now used to treat lameness associated with osteoarthritis in the equine patient. Researchers at the Equine Orthopaedic Research Center at Colorado State University published a study in the April 2009 edition of The American Journal of Veterinary Research on the efficacy of using ESWT for the equine patient diagnosed with osteoarthritis.

We know that osteoarthritis is caused by a degenerative process that slowly breaks down and destroys cartilage in the joint. Think of cartilage as the cushion between the two skeletal processes. Without it, we have a condition of “bone on bone” whenever the horse moves the joint; painful and often debilitating. Because there is no known trigger for osteoarthritis, it’s considered to be a condition of wear and tear.

ESWT is a non-invasive procedure that works by generating pulses of sound through the skin to treat pain in soft-tissue. The researchers at Colorado State University included 24 horses in the study, all diagnosed with osteoarthritis in the knee. The group was split into thirds with the first group receiving just ESWT, the second group receiving an ESWT placebo, and the third group, receiving ESWT and intramuscular injections of polysulfated glycosaminoglycan (PSGAG), a naturally occurring substance contained in healthy synovial fluid.    

The researchers studied degree of lameness and analyzed the synovial fluid on all 24 horses, as well as the cartilage and synovial membranes. According to this study, the horses receiving ESWT had a significant improvement when compared to the horses that received the placebo. Horses that received both ESWT and intramuscular injections of PSGAG showed the most improvement. It’s important to point out ESWT showed no disease-modifying capabilities, meaning, it doesn’t seem to change or alter the course of the disease process in any way, although it did decrease lameness considerably. No adverse events were reported from any of the treatment modalities.

Based on this study, researchers conclude that ESWT is a viable treatment option when used in conjunction with a disease-modifying drug, like a PSGAG (trade name, Adequan®).

Interleukin 1 Receptor Antagonist Protein (IRAP)

If you think IRAP sounds like something from The X-Files, well…you’re not far off. IRAP is an exciting new gene therapy meant to wage battle against osteoarthritis in your horse. Interleukin 1 is a type of cytokine, a chemical that is secreted by healthy cells to attack infection or in the case of osteoarthritis, an inflammatory response. In a horse with osteoarthritis, Interleukin 1 is the enemy. Its war-like behavior actually accelerates the degeneration of cartilage.

Enter Interleukin 1 Receptor Antagonist Protein or IRAP. IRAP is designed to stop the damaging effects of Interleukin 1 in its tracks. Treatment is relatively simple. Your veterinarian will collect blood from your horse’s jugular vein. The syringe used to collect the blood contains tiny glass beads that encourage production of the antagonist protein and an anticoagulant. Once the blood is harvested, it’s incubated and centrifuged to separate the plasma from the blood. Plasma is teeming with IRAP, just the thing to combat osteoarthritis. Treatments usually consist of injections once a week for three weeks. IRAP is exciting because unlike other modalities, it appears to have the ability to stop cartilage from degrading any further and may even promote healing.

Stem Cell Treatment

While stem cell treatment already exists in both equine and canine therapy, its use is still very limited. Current treatment consists of aspirating fat cells, most often harvested from bone marrow, directly from the injured animal. Cells are then sent to a lab and cultured into the desired tissue cells. Because aspiration of the fat cells can lead to infection, researchers like Dr. Paul Verma of the Monash Institute of Medical Research in Australia are determined to find less invasive ways to collect and grow stem cells. Verma has partnered with the U.S. based company, Viagen, to develop equine embryonic stem cell lines, with the goal of creating a “bank” of stem cells preserved for individual horses. They’ve already developed techniques to harvest stem cells from equine embryos. The goal is to coax the embryonic stem cells to become the desired tissue cells, including ligament, tendon, cartilage, or even bone. The research is exciting and new discoveries may ultimately benefit human medicine as well.

There have been several major advances in equine medicine in recent years. If your horse suffers from joint disease, don’t let him suffer in silence. Ask your veterinarian about some of these innovative treatment options today.