Just as a human athlete can develop cartilage loss, so, too can equine athletes.
The condition can result from repetitive exertion or trauma, but it might also be biological in its origins, according to Dr. Eric Carlson, DVM, Rood & Riddle Equine Hospital.
Dr. Carlson, a surgical resident with the world-renowned Kentucky practice, offers his opinion on treatments and causes of cartilage loss in a Veterinary Answers Q&A with Off-TrackThoroughbreds.com.
Q: I recently wrote about a transitioning OTTB who was found to have cartilage loss in his ankles. What factors determine a future career for an animal with this condition?
Ultimately the horse will determine what degree of exercise they can comfortably perform.
There is not always a correlation between degree of cartilage loss, radiographic changes and comfort level.
As a result, we depend on the horse’s comfort level to determine what type/degree of exercise they are best suited for.
In general, the larger the area of cartilage loss and the more severe the radiographic changes, the less likely the horse will be able to perform as a high level athlete.
Q: How does cartilage break down in the ankles? Is genetics thought to be a major cause, or is it strictly a wear-and-tear issue?
Osteoarthritis (OA) in the horse usually occurs secondary to trauma, but it can also be developmental in origin.
When a joint is traumatized, both physical (cartilage or bone fragments) and biological (inflammatory mediators) debris are released.
This debris damages the hyaline cartilage that lines the joint surface.
Unfortunately, hyaline cartilage cannot be regenerated. The damaged hyaline cartilage is replaced by fibrocartilage, which contains scar tissue and is inferior for lining the joint surface.
Q: What are the treatment options available for a horse with this condition? And, what are the price points?
Treatment for OA can be classified as disease modifying or symptom-modifying.
Symptom-modifying treatments are aimed at decreasing or resolving the clinical signs (lameness, swelling) that accompany OA, while disease-modifying treatments are aimed at preventing additional destruction of hyaline cartilage and disease progression.
Disease-modifying treatments options available for patient use include stem cells, platelet rich plasma, IL-1ra (IRAP), PSGAG, and Hyaluronan.
Unfortunately these treatment options are not able to substantially regenerate damaged hyaline cartilage, but they may help prevent further damage from occurring.
Symptom-modifying medications include nonsteroidal anti-inflammatory drugs (phenylbutazone, flunixin, firocoxib, etc.), and corticosteroids (methylprednisolone, triamcinolone, etc.).
Symptom-modifying drugs are useful because they reduce inflammation and provide pain relief.
However, while these drugs relieve pain and inflammation in the joint, they may not prevent further damage from occurring.
Typically, if OA is severe, symptom-modifying medications will not provide long-term improvement. Prices vary significantly from a few dollars per treatment for phenylbutazone to several thousand dollars for stem cell treatment.
Q: Is there anything new on the horizon, in terms of nutritional additives or surgical intervention, to alleviate the discomfort of this condition?
While there are many nutritional additives on the market, very few have controlled scientific research supporting their beneficial use in the horse.
There is significant ongoing research involving the use of stem cells and other biological products for the prevention and treatment of OA.
Additional time and research will influence our future treatment options.
Q: How can a race owner avoid or prevent cartilage loss in his horse?
There is no way to completely prevent cartilage loss in the athletic horse.
Any athlete, horse or human, has the potential to develop OA over time.
Appropriate preventative veterinary care, feeding, shoeing and conditioning are beneficial to ensure the horse is fit and healthy.
If the horse becomes lame, develops joint swelling, or changes in level of performance, then a veterinarian should be consulted immediately.
Prompt evaluation is important so that a diagnosis and treatment can be pursued before additional damage occurs in the affected joint.