Although not usually life-threatening, arthritis causes your horse pain and can be career-ending. In fact, a research report from Michigan State University's McPhail Equine Performance Center calls degenerative joint disease the single most common cause of early retirement for sport horses.
Scientists are working hard on several studies that might eventually present realistic solutions for actually reversing the arthritis process–regenerating cartilage and synovial fluid through modern miracles such as gene therapy. While awaiting such exciting developments, you don't have to sit back and watch your horse suffer. Arthritis can be managed now. Using a multi-pronged approach, you can improve the affected joint's range of motion, reduce pain and inflammation, and significantly slow the degeneration process, resulting in a comfortable horse with a prolonged performance career.
Early, Accurate Diagnosis Is Key
"The most important thing is to get a diagnosis," says David Frisbie, DVM, PhD, Dipl. ACVS, a Colorado State University assistant professor and researcher with the school's Equine Orthopaedic Research Center (EORC). By doing so, you wil learn not only which joint is arthritic, but also how severe the damage is, which of course affects the treatment decisions.
It's important to achieve an accurate diagnosis as early as possible, since arthritis does irreparable damage if left to its own devices too long. Unfortunately, the signs of the disease are subtle, ranging from performance problems (resisting lead changes, refusing jumps, etc.) to minor heat or swelling of the joint. If you suspect trouble, call your veterinarian. He or she will perform diagnostic nerve blocks to pinpoint the affected joint, followed by X rays to assess severity and rule out other problems.
Your veterinarian can also help you determine the best course of management for your horse. In particular, Frisbie recommends finding someone who works in orthopedics or musculoskeletal disorders. "They have experience using a variety of medications," he notes, adding that this will make the treatment choices less of a guessing game than if you were to visit the local tack shop seeking solutions.
In general, the primary goals of arthritis management are three-fold–maintaining or improving range of motion, reducing pain and inflammation, and stopping–or at least slowing–cartilage degeneration. It makes sense, then, that most management plans are multifaceted, relying on a number of strategies to keep the horse comfortable and the disease process under control.
Preserve Range of Motion
Once upon a time, humans with arthritis were coached to take it easy and not stress their already worn joints. Then research revealed that exercise and activity actually helped reduce the pain of arthritis and improve the sufferer's ability to function. The same is true with horses. Although rest is useful for an acute onset of arthritis, chronic cases typically benefit from exercise, whether it's turnout or riding.
Berkley Chesen, DVM, a practitioner with Hagyard-Davidson-McGee Associates in Lexington, Ky., notes that exercise should be controlled. "Turnout may be okay for some horses, while others will actually do little walking or trotting and may need to be encouraged to work a bit," she says.
Activity can yield numerous benefits for the arthritic horse, including strengthening the soft tissues that support the joints and helping lubricate joints by promoting circulation of synovial fluid. Conversely, inactivity compromises joint health. Just as you tend to stiffen up after sitting still for long periods of time, so will your horse stiffen up when he's been confined to a stall day after day.
All this said, it should be noted that in some cases, a veterinarian will recommend stall rest for an arthritic horse. This is particularly true if the veterinarian is concerned that discomfort will cause the horse to place excess stress on unaffected limbs, potentially leading to secondary soundness issues. Full rest, though, is usually a temporary solution that will eventually lead to an exercise program.
Of course, you might need to make concessions in your riding program for your arthritic horse. As Frisbie says, "The more you ask of the horse, the more cognizant you need to be of warming up, cooling down, and building your horse's condition level up."
Along these lines, stretching and passive range-of-motion exercises act in the joint's favor. They help keep the supporting soft tissues limber and supple, have been shown to reduce scar tissue buildup, and might even help heal damaged cartilage.
Topical products such as liniments can also be useful, says Frisbie. "With arthritis, you often see a little swelling. If you put on some liniment and wrap it, it usually tightens up, and the horse seems to feel better," he explains. "It's like putting (mentholatum rub) on yourself." In fact, a study conducted by Alicia Bertone, DVM, PhD, and colleagues at The Ohio State University found that topical application of dimethyl sulfoxide (DMSO) decreased joint inflammation.
Traditional heat/ice therapies are also useful in remedying the aches of arthritis. There's even validity to the use of alternative therapies such as chiropractic, acupuncture, and shockwave, says Frisbie. Although they might not act on the arthritis itself, they can help ease secondary discomfort. For instance, says Frisbie, "Say a horse has arthritis in the hocks. He may subsequently get lumbar (back) pain associated with that. You can do chiropractic, acupuncture, or even shockwave therapy on the lumbar region, and the horse will ride and travel better."
Kathy Ott, DVM, a practitioner with Equine/Small Animal Medical Center in Lakeville, Minn., believes that acupuncture is also a beneficial treatment. In comments at the clinic's web site, Ott notes that acupuncture can increase circulation, relieve muscle spasm, and even relieve pain by spurring the release of endorphins and cortisol into the body.
The drawback to any of these therapies, says Frisbie, is that pain will return because you've only provided a temporary bandage, not a solution to the underlying problem.
Reduce Pain and Inflammation
Inflammation is perhaps the most important culprit to address in managing arthritis, says Frisbie. "We know that inflammation drives the arthritis process," he explains. "You can drop the process from third to first gear by stopping the inflammation."
While many anti-inflammatory medications exist, there isn't much useful information comparing the flood of products to each other, or dictating which are best suited for specific applications. Based on research at EORC, Frisbie has put together a subjective ranking system based on the ability of a product to reduce clinical signs of pain and slow the arthritic process.
Topping this tower of power are corticosteroids. Also known as steroidal anti-inflammatory drugs (SAIDs), these medications–administered by intra-articular injection–are widely considered the gold standard when it comes to quickly reducing pain and inflammation. Frisbie says there are three corticosteroids commonly used in managing equine arthritis– triamcinolone, methylprednisolone, and betamethasone. Of these, Chesen uses only the first two, and Frisbie ranks triamcinolone first in effectiveness, noting that one study showed the product reduced pain and was protective to cartilage metabolism. (Frisbie acknowledges that the study didn't test all dosage levels or the effect of frequency of use.)
While SAIDs are the most powerful anti-inflammatories, NSAIDs–non-steroidal anti-inflammatory drugs–are next in line and are probably used more than any other drug to combat the pain and inflammation associated with equine joint (and soft tissue) troubles. The NSAIDs most popular in the horse world include phenylbutazone (Bute), flunixin meglumine (Banamine), ketoprofen, and aspirin.
Effective or not, both NSAIDs and steroids have come under fire in recent years because of side effects. For instance, some studies have indicated that corticosteroids can actually inhibit cartilage metabolism.
Meanwhile, some people believe that NSAIDs simply mask pain without addressing underlying problems. This would allow the horse to remain active on an injured limb, leading to further degradation of the cartilage and pushing the arthritic process forward. Both Frisbie and Chesen dispute this theory. After all, notes Chesen, NSAIDs do reduce inflammation, thus reducing the impact of a known driver of the arthritis process. Furthermore, Frisbie says that no conclusive evidence has been presented to support the notion that NSAIDs cause joint degeneration.
For now, the bottom line, Frisbie says, is that, "NSAIDs have been shown to be more potent at reducing inflammation than at damaging cartilage." And to avoid the one known danger of extended NSAID use–gastric trouble, such as ulcers–he recommends using the drugs only for short periods of time.
While corticosteroids and NSAIDs can be used alone, veterinarians usually recommend pairing them with hyaluronic acid (HA) or polysulfated glycosaminoglycans (PSGAGs). HA and PSGAGs are more commonly known by the commercial names Legend (an HA product) and Adequan (a PSGAG product). Both are particularly useful in managing arthritis because they have the ability to improve the health of cartilage and joints.
HA is found naturally in healthy joints as part of the synovial fluid that helps lubricate the joints, cushion the cartilage, and protect the synovial membrane. In arthritic horses, levels and quality of HA are low, resulting in thinned synovial fluid that is less effective at protecting and lubricating the joints. Research has shown that HA injected into the joint or into the vein (IV) works like naturally occurring HA, reducing inflammation and catalyzing increased production of HA in the horse, thus helping an arthritic joint improve. In fact, a study conducted at Colorado State University, in which Frisbie participated, showed that IV injections of Legend decreased the concentrations of inflammation-causing proteins in arthritic joints, lowered inflammation, and lessened lameness.
Also, studies have shown the effectiveness of PSGAGs in not only reducing inflammation and discomfort, but also improving the overall health of the joints. PSGAGs can help increase HA production, assist with joint lubrication, and help repair cartilage. According to Adequan manufacturer Luitpold Pharmaceuticals, PSGAGs accomplish this last feat by binding to damaged cartilage and suppressing enzymes that damage cartilage and dilute synovial fluid. The product can be administered either directly into the joint or by intramuscular injection.
One More Ally
Frisbie places oral treatment products–such as glucosamine sulfate (a basic building block of connective tissue and joints) and chondroitin sulfate (a component of cartilage)–at the bottom of the potency ladder. "Oral products certainly work and are quite safe," he notes, "but it's my belief that they are not as potent as injectables, although they often cost just as much." Still, he says, "They can be useful when used in addition to injectables, if economics allow."
A Management Protocol
It's one thing to know all the possible medications available to help your horse live comfortably with arthritis. But how do you put them all together into an actionable plan? While different veterinarians have different opinions, and different situations call for slight adjustments, Frisbie does have a standard protocol he uses as a guideline for his arthritis cases.
"After an accurate diagnosis establishes that (the condition) dictates medical management, I typically inject the joint first with a corticosteroid–specifically, Vetalog (triamcinolone)–plus an HA product," he explains, adding that his initial treatment also includes seven to 10 days of Bute. "That treats the arthritis aggressively at the start, stopping the inflammation. Then I'll give two IV injections of HA a week apart, and I continue using monthly injections of IV Legend as a prophylactic, for maintenance."
Chesen's general protocol calls for four to six weeks of Adequan and Legend injections, coupled with oral supplements, which she says generally require a "loading phase" before they really start to make a difference. "That way, by six to eight weeks, the oral supplements are usually at a level to clinically help the horse without costly injections," she says.
Of course, severity of the individual horse's arthritis affects the maintenance program, and Frisbie believes in letting the horse's condition–not a rigid schedule–dictate when the next treatment is due. "For instance, a horse with a mild case may not need another treatment for a year, while one with more severe damage may need injections every three to six months," he explains.
Regardless of severity, he believes it's vital to stop the cartilage degeneration as quickly as possible, which is why he opts for the intra-articular injection as a first treatment. However, Frisbie prefers IV administration for ongoing treatment. "Any time you stick a needle in a joint, there is the risk of infection. Although the risk is quite low–probably less than 1%–if you don't have to take a risk, why do it?" he says. "Plus, we feel that the IV injection may work just as well as injecting into the joint and also be effective at getting to other pains and aches that maybe haven't been identified yet. That systemic approach appeals to me after the first treatment or once the inflammation is under control."
In order to make your management plan truly systemic, you should combine medication treatments with the basic elements mentioned earlier–including appropriate exercise, stretching, and therapies (from ice and heat to massage and acupuncture) as needed. You'll likely find that your efforts will pay off not only in a longer active life for your horse, but a more comfortable life, as well.