Think of them as the silent sufferers: the millions of dogs who hobble among us, creaking away on swollen joints and dwindling cartilage. Most are older, but the years didn’t make them that way. Arthritis did.
Osteoarthritis is the biggest cause of chronic pain in U.S. dogs. According to most estimates, it affects more than 20 percent (that’s 10 to 12 million animals).
Technically speaking, osteoarthritis, or OA, is a degenerative disease involving one or more joints in a dog’s body. It most often shows up in middle-aged or older dogs, although there’s no standard age of onset, explains Jamie Gaynor, DVM, MS, director of the Animal Anesthesia and Pain Management Center in Colorado Springs, Colo.
But OA isn’t just an old dog’s disease, nor is every dog destined to be arthritic. OA is generally triggered by excessive wear in one or more joints, but dogs who have joint irregularities are more likely to develop arthritis in the affected joint. These irregularities can be caused by trauma—an accident or injury—or by a developmental deformity, such as hip or elbow dysplasia, which is a genetic condition that develops in a dog after birth.
Other factors that can contribute to OA are obesity (see sidebar) and overuse. This is a problem for racing dogs as well as for many working breeds; they may not be herding sheep or pointing at birds for a living, but many still feel compelled to run around as though they were.
Osteoarthritis is tough to manage, in part because it’s cyclical: Inflammation creates pain as well as physical changes that force the joint to move in an unnatural way, creating more pain and inflammation. Once it gets started, arthritis is difficult, if not impossible, to stop.
What’s more, just controlling the pain of arthritis is anything but simple. Researchers have found that arthritis pain follows several different pathways and creates changes in the dog’s central nervous system, which means that keeping an arthritic dog comfortable most often requires more than one type of pain relief.
There’s no cure for OA—treatment generally focuses on treating the discomfort and slowing the loss of cartilage and damage to the joints.And vets agree that there’s no silver bullet: No drug or therapy or supplement works on every dog, and no two dogs respond in exactly the same way to any treatment.
But there are steps that you can take to slow the progression of arthritis and keep your dog as happy and active as possible.
Veterinarians’ offices, pet supply stores and Internet shopping sites are brimming with supplements, all promising to have your creaky old dog prancing like a puppy. But while there’s plenty of snake oil out there, some supplements do seem to work: some on the pain, others on the inflammation and still others on the cartilage itself.
This last group, known as diseasemodifying agents, can create changes in the dog’s body that have a direct impact on the progression of a disease, explains Dawn Boothe, DVM, PhD, professor and director of the clinical pharmacology laboratory at Auburn University’s College of Veterinary Medicine in Auburn, Ala. In a dog with arthritis, these supplements can make the cartilage healthier and better able to fight off the damaging effects of OA.
The supplements listed here can be combined with other remedies, but check with your vet before adding them to your dog’s diet. Give any supplement at least four weeks to work, says Carvel G. Tiekert, DVM, executive director of the American Holistic Veterinary Medical Association.“If you don’t see any changes after six weeks,try something else,”he says. (For another cautionary note, see the final page.)
Glucosamine and Chondroitin Sulfate. These substances provide the building blocks for polysulfated glycosaminoglycans, or PSGAGs, which are long-chain molecules that hold water and give cartilage its cushion. Research shows they can be very effective in both animals and humans. A recent study (Grainne McCarthy, James O’Donovan, et al., published in The Veterinary Journal 2007; 174:54–61) found that arthritic dogs given a supplement of glucosamine and chondroitin for 10 weeks had significantly less pain than dogs who didn’t get the supplement.
However, not all glucosamine is created equal. “There’s a huge range in quality of these supplements,” says Dr. Boothe. To be sure you’re getting your money’s worth, stick with products that have been proven effective in studies. Both Dr. Gaynor and Dr. Boothe recommend products from NutraMax Labs, which manufactures Cosequin and Dasuquin. Glyco-Flex III, from Vetri- Science Labs, is also well researched, says Dr. Gaynor.
Supplemental MSM appears to act as an analgesic (like aspirin). In a few small studies, it has improved pain and physical function in people with OA.
DLPA is a synthetic amino acid that seems to relieve pain. One component of DLPA, D-phenylalanine (DPA), has been shown to decrease chronic pain and boost the pain-relieving benefits of some medications (and of acupuncture) in animals and humans.
Extracts from cold-water fish contain omega-3 fatty acids, which reduce inflammation. Human studies show that fish oil helps alleviate pain, and a 2008 study found that fish oil improves the synovial fluid in dogs with inflammatory joint disease following a ligament injury.
Avocado/Soybean Unsaponifiables (ASUs).
ASUs (the leftovers from soap production) act as anti-inflammatories, and can inhibit the breakdown of cartilage and promote its repair.
Perna canaliculus (Green-lipped Mussel).
Extracts from this New Zealand mollusk have been shown to reduce joint pain and swelling in arthritic dogs.
Nonsteroidal Anti-inflammatory Drugs, or NSAIDs. The go-to pain medications in nearly every vet’s arsenal are NSAIDs (NSAIDs for humans include aspirin and ibuprofen). The NSAIDs approved for use in dogs include Rimadyl,Metacam, Deramaxx, Previcox and Zubrin.
Of these, the first four are COX inhibitors (they target the cyclooxygenase, or COX, enzymes responsible for inflammation and pain). “Some dogs respond better to one, but they all have essentially the same mechanism,” says Dennis Caywood, DVM, MS, a diplomate with the American College of Veterinary Surgeons in Minneapolis.
The drug Zubrin blocks the COX enzymes as well as a second type of chemicals, called leukotrienes, meaning it addresses two different inflammation pathways. This could make it more powerful than the others, says Dr. Boothe. While NSAIDs can be very effective, they also carry the risk of side effects, including damage to the dog’s gastrointestinal tract. They require careful dosing, and can’t be combined with other NSAIDs.
Corticosteroids, or Glucocorticoids. Veterinary glucocorticoids, including prednisolone and methylated prednisolone (Cortisate-20, Depo-Medrol and Medrol), are steroidal medicines that attack inflammation. Unfortunately, they also attack the dog’s tissues.
“As a pharmacologist, I have a real bias against using steroids to treat chronic pain,” says Dr. Boothe. Glucocorticoids can cause weight gain, incontinence and lethargy. Long-term, they’ve been linked to compromised immunity,muscle and bone loss, and a potentially fatal shutdown of the adrenal glands. Moreover, glucocorticoids actually damage cartilage. “Veterinarians have used them in older animals with the idea that they were the only thing that would relieve the dog’s pain,” says Dr. Boothe. “But now there are better options.” However, she says, glucocorticoids might be used in a one-time, direct-tothe- joint injection (see hyaluronic acid, following).
Tramadol (Ultram) is a synthetic opiate. It’s strictly a pain reliever, says Dr.Gaynor, not an anti-inflammatory, so it can be safely combined with NSAIDs and many other drugs.
Medicines for Neuropathic Pain.
Two drugs for humans, gabapentin and amantadine, also address the neurologic components of dogs’ pain—how the pain messages are carried to the dog’s spinal cord and brain. These drugs also reduce “windup,” a phenomenon in which a dog’s nerves become overly sensitized, leading her to feel pain from things that otherwise wouldn’t hurt at all.
Adequan is a prescription PSGAG that works like glucosamine and chondroitin, only faster, says Dr. Boothe.
Hyaluronic acid, or HLA, is a natural source of PSGAGs (it’s found in connective tissue and synovial fluid).“We’ve had very good luck with HLA,” says James Cook, DVM, director of the Comparative Orthopedic Laboratory at the University of Missouri–Columbia College of Veterinary Medicine. “We do a series of three joint injections, the first with HLA and Depo-Medrol, and the last two with just HLA. It’s been very effective, even in dogs with advanced OA.”
HLA is also given orally, but there’s no evidence that it’s effective that way, says Dr. Boothe.
Physical therapy can be very helpful, says Dr. Caywood.“Strengthening exercises and activities like swimming or using an underwater treadmill build the muscles in and around the joint, making it easier for the dog to get around,” he explains.“Rehab” swimming is done under controlled circumstances, with the dog wearing a safety vest, the water at optimum temperature and constant monitoring. A vet trained in veterinary physical rehabilitation may be able to offer other options as well.
Low-level lasers have been shown to reduce pain and inflammation and to stimulate healing in humans and animals.
Extracorporeal shock wave therapy (ESWT) uses powerful, high-energy sound waves to treat OA (it’s painful, so dogs are typically sedated for this treatment). Pulsed signal therapy (PST) delivers small, imperceptible pulses of electromagnetic energy. A handful of studies have shown that both therapies can be effective in animals as well as humans.
Acupuncture and Heat.
Studies suggest that this ancient Chinese treatment can reduce stress, pain and inflammation. “We’ve seen some great results in dogs with arthritis,” says Dr. Gaynor, who is also certified in veterinary acupuncture.Another chi stimulator, far infrared or radiant heat, has been used to reduce discomfort as well.
Regenerative Stem Cell Therapy.
Arthritic dogs can be treated with stem cells harvested from the dog’s own fat stores (cells are harvested, re-engineered, then injected into the arthritic joint). A recent study found that treated dogs had significantly less lameness and pain and better range of motion. The stem cells seem to help regenerate cartilage and other tissue, providing pain relief in the process, says Dr. Gaynor.
Arguably the last choice in any menu of treatments, surgery can offer an arthritic dog a chance at real relief. Veterinary surgeons can remove painful bony growths and other problems arthroscopically, and can partially or completely replace a dog’s hip joint, all with generally good results. Total elbow replacement is available as well, although the success rate in elbows isn’t as high as that in hips, says Dr. Caywood. Right now, hips and elbows are the only joints that can be surgically replaced.
Canine OA has probably been around as long as canines. The difference now, says Dr. Cook, is that we’re better at recognizing it. And we’re more concerned with treating it than dog owners of the past might have been.
“Now, we’re looking at ways to spot arthritis before it gets too advanced,” he says. Researchers are also looking for genetic biomarkers—factors in the dog’s blood or joint fluid that would show the likelihood of his developing OA in the future. He encourages owners to know their dog’s predisposition for inherited joint diseases (the Orthopedic Foundation for Animals [offa.org] publishes dysplasia statistics for various breeds), then talk to a vet about ways to minimize the OA that might occur. “Anything that you do early in the dog’s life will have much more impact than what you do after the problem has developed,” he says.
The supplement industry is not monitored by the FDA, and studies have shown that the quality and amount of a supplement are sometimes less than indicated on the label. The adages “do your homework” and “you get what you pay for” apply.