At some point in many athletic horses’ career, they will develop osteoarthritis. Osteoarthritis is inflammation in a joint that leads to cartilage damage and eventually bony changes. The inflammation and resulting changes in the joint are painful, causing lameness or stiffness and sometimes heat, swelling, or extra fluid in the joint. The most common joints affected by osteoarthritis are the lower joints of the hock, also known as bone spavin, but any joint can be affected.
Unfortunately, there is no cure for osteoarthritis. Due to the chronicity of the disease, long term therapies are often required and can have side effects. Treatments of OA are divided in two categories- treating just the signs of the disease (pain/ lameness) and treating the disease process. Often a combination of therapies is used to get the best results. The ultimate goal is to prevent further progression of the disease while improving function and comfort of the affected joint(s).
For successful management of osteoarthritis, an accurate diagnosis is needed. A complete lameness exam, performed by a veterinarian, is necessary to make this diagnosis.
There are many available therapies for OA and many make claims that seem too good to be true. With this blog, we will sift through some available products and direct you to the ones with research behind them. In part one, we will discuss non-steroidal anti-inflammatory drugs and joint supplements; part two will cover systemic and intra-articular therapies, as well as future directions in treatments.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
Symptomatic treatments of this disease include non-steroidal anti-inflammatory drugs (NSAIDs). The most common are phenylbutazone (bute) and firocoxib (Equioxx). These drugs do a very good job of treating the pain and lameness associated with the disease and immediate results will be seen. However, while the anti-inflammatory action does help with the inflammation caused by this disease, it does not address the underlying disease process. Use of these drugs at competitions is also regulated by the FEI, USEF, and other horse show organizations. These drugs are often used for a short period of time to improve flare-ups of the disease. Long term use of these medications can have unwanted gastrointestinal (stomach and colon ulcers) and kidney side effects.
Oral Joint Supplements
The goal of oral joint supplements is to decrease the need or dose of other medications (and their side-effects) while slowing the progression of the disease. Joint supplements are classified as nutraceuticals and are not regulated by the Food and Drug Administration. There is no requirement to prove safety or efficacy. Joint supplements vary tremendously in ingredients, amount of active ingredients, and consistency from batch to batch. Even products with a “guaranteed analysis” on the package many not meet that label claim. The products that have the most inconsistency tend to state they are a “complex,” formula,” or “blend” with no amount of each ingredient on the package. Lot numbers and expiration dates also give some evidence that the product is reputable (but no guarantee).
However, many horse owners and trainers have noticed a response to treatment with these supplements. The goal of these compounds is to provide the precursors for cartilage in excess so they are readily available if repair is needed. Glucosamine and chondroitin, under the brand name Cosequin, is the only product that has undergone scientific testing. In some studies, Cosequin did improve lameness. Another study of glucosamine, chondroitin, and MSM combined showed some improvement in range of motion. No scientific studies have found MSM, on its own, to improve the signs of OA. Fatty acids have been beneficial in humans, but no published studies have proved efficacy in horses. There are many herbal, vitamin, and mineral supplements purported to treat OA, though no studies have proven their effectiveness or safety. Often, we recommend Cosequin or Cosequin ASU as a starting point for treating cases of mild osteoarthritis. Other brands may also be effective, but keep in mind the lack of regulation and consistency with these products. Your pocketbook will thank you!
Join us next month for our discussion of systemic and intra-articular therapies.