Osteoarthritis is a common issue for joint health for pets that can be derived from weight management issues, genetic predispositions, or a combination of the two. Using a multi-modal approach with early attention to nutrition, ongoing weight management, and joint supplements, a veterinary practitioner can learn to prevent and successfully manage the osteoarthritic canine patient.

Osteoarthritis in Pets

Osteoarthritis (OA) is a common problem for pets, particularly in older dogs, but there are some misconceptions about osteoarthritis in dogs. Owners often think of OA as an old dog problem, in part because OA is most often diagnosed in middle-aged and older humans. In contrast to humans, though, in dogs the majority of OA cases are caused by genetically driven developmental problems during the puppy years; this is called developmental orthopedic disease (DOD).

Developmental orthopedic disease (DOD) refers to a genetic tendency for skeletal abnormalities that affect primarily large- and giant-breed dogs as well as dog breeds with chondrodysplasia or “short-leggedness” i.e. Basset Hound, Pembroke Welsh Corgi, and Dachshunds. DOD in the young, growing dog may result in:

• Hip dysplasia
• Elbow dysplasia
• Osteochondritis dissecans (OCD) of the humeral head, femoral condyles, and ridges of the talus, cranial, and cruciate ligament (CCL) disease and injuries
• Intervertebral disc disease
• Patellar luxation (1-5)

The role of nutrition in development of musculoskeletal disease in growing dogs has been recognized for decades. Nutrient excesses of calcium from diet or supplements as well as high calorie intake are risk factors for the DOD-prone breeds. Calorie-dense pet foods and overfeeding should also be avoided. Currently practitioners should be recommending feeding at-risk puppies pet foods that are labelled with the following Association of American Feed Control Officials (AAFCO) statement:

“[Pet Food Name] is formulated to meet the nutritional levels established by the AAFCO Dog Food Nutrient Profiles for growth/all life stages including growth of large-size dogs (70 lbs or more as an adult). (1-6)

Weight Management for Osteoarthritis in Pets

Overweight/obesity not only results in excess forces on joints and articular cartilage, but adipose tissue is also metabolically active and pro-inflammatory. Mechanical “wear and tear” and inflammation in an overweight canine patient may have a negative impact on joint health for pets, causing pain and inactivity, which results in further weight gain; therefore, a vicious cycle ensues. (7-12) Practitioners need to identify the patient who is “at risk” for osteoarthritis, i.e. one who is becoming overweight. Using body weight and assigning a body condition score, a measurement of body fat, is essential for managing these patients to prevent the comorbidities associated with obesity and osteoarthritis.

Practitioners should educate clients about keeping young, at-risk dogs at an ideal body condition score to extend lifespan and delay the development of osteoarthritis. A long-term study was performed with 48 Labrador Retriever puppies genetically at risk for hip dysplasia. They were divided into two dietary groups:

1. Group 1 fed an adult maintenance dog food at 0.2700 kJ of metabolizable energy per kilogram of body weight per day
2. Group 2 fed an adult maintenance dog food at 0.2025 kJ of metabolizable energy per kilogram of body weight per day (75 percent of the amount fed to Group 1)

Restricted fed dogs (Group 2) compared to non-restricted fed dogs (Group 1) lived an average of 1.8 years longer, weighed less, had better body condition scores, and had longer delays to development of chronic disease, including osteoarthritis. Maintaining optimal or slightly lean body condition in the canine patients can be challenging, but as this study demonstrates it can decrease the development of osteoarthritis and/or delay of onset of clinical signs of osteoarthritis. (13-16)

If an osteoarthritic dog is already overweight or obese, studies support the idea that weight reduction can improve quality of life and osteoarthritis management. (17-19) In a study of 14 client-owned dogs with clinical and radiographic signs of osteoarthritis, body weight reduction of at least 6.1 percent resulted in a significant decrease in lameness, and a loss of at least 8.9 percent body weight resulted in improvement in kinetic gait analysis.₂₀

These results confirm that weight loss is an important treatment modality of obese dogs with osteoarthritis and that noticeable improvement may be seen after modest weight loss of at least 6 percent. (20) Practitioners should educate owners about the pain and debilitating effects of obesity in a dog with osteoarthritis followed by recommending a safe and effective weight loss program.

Common Supplements for Osteoarthritis in Dogs

Besides nutrition and weight management, specific joint support supplements can be used to manage joint health for pets, specifically osteoarthritis in dogs. Understanding the ingredients found in joint support supplements will enable the practitioner to utilize these to manage osteoarthritic patients.

Omega-3 fatty acids

Fish oil supplements that contain omega 3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to help resolve inflammation in disease states such as osteoarthritis. (21-25) Other lipid components like pro-resolving lipid mediators, bioactive peptides, and other fatty acids may also play a role in some of the beneficial effects that have been demonstrated in the literature.

Glucosamine and chondroitin sulfate

Other common ingredients found in joint support supplements include glucosamine and chondroitin sulfate, which are purported to slow or alter the progression of osteoarthritis. Glucosamine and chondroitin are precursors for glycosaminoglycans, which are a major component of joint cartilage; therefore, supplemental glucosamine and chondroitin may help to maintain or rebuild cartilage. (26-31)

Green-lipped mussel

Perhaps a less familiar ingredient used in supplements for joint support is the New Zealand green-lipped mussel (Perna canaliculus; GLM). How did the GLM become an “active ingredient” in both human and animal joint supplements? The GLM is endemic in the coastal waters of New Zealand and has been a part of the staple diet of the indigenous Maori people for hundreds of years. Interestingly, the benefits of the GLM stemmed from the observation that these coastal communities consuming GLM had a lower incidence of arthritis than their European or inland counterparts. (32-34) The GLM is not only a rich source of glycosaminoglycans, but it also has anti-inflammatory effects most likely derived from omega-3 polyunsaturated fatty acid content.

Early studies of GLM found no significant benefits of GLM, but at the time, the extracts were not well preserved. In 1986, dried mussel extracts became available that were stabilized with a preservative. These stabilized lipid extracts used in more recent studies have been shown to be more effective than a non-stabilized extract at inhibiting inflammation. Today there are over 150 publications on the benefits of GSM with many in vitro and in vivo trials using GLM extracts to evaluate its effectiveness in alleviating the symptoms of inflammation and osteoarthritis in rodents, humans, dogs, cats, and horses. (32-34)

Several studies indicate that GLM extracts are a safe, logical supplement for the veterinary patient with osteoarthritis:

In a randomized controlled clinical study of 31 dogs with arthritis, GLM powder was added to a test diet. When compared to control groups, dogs on the GLM test diet had significant improvement in subjective arthritis scores, joint swelling, and joint pain. (35) Another randomized-controlled study of 45 dogs with osteoarthritis reported dogs receiving GLM had improvement in mobility when compared with placebo.(36)  A study of 81 dogs with presumptive osteoarthritis reported improved clinical signs on day 56 of the study in dogs receiving GLM. (37) An uncontrolled study of 85 dogs fed a GLM supplemented diet for 50 days showed reduction of a composite arthritic score when compared with baseline scores on various diets dogs were consuming.(38)

Boswellia serrata

Another ingredient that has found its way into joint supplements are extracts from Boswellia serrata, a medicinal plant found in the mountainous regions of India, Northern Africa and the Middle East. B. serrata is also commonly known as guggul, Indian olibanum, loban, or kundru. Since ancient times, Boswellia has been an important traditional medicinal plant used for the treatment of various ailments. More recent in vitro and in vivo studies have demonstrated the immense therapeutic potential against several conditions especially those involving inflammation. (39-40)

Extracts of the gum resins of Boswellia contain numerous pentacyclic triterpenic acids, with acetyl-11-keto–boswellic acid (AKBA) and 11-keto-β-boswellic acid (KBA) being primarily responsible for its anti-inflammatory effects. Studies in vitro and in vivo suggest these active components in Boswellia extracts (BSE) may inhibit the 5-lipoxygenase pathways as well as microsomal prostaglandin E2 synthase to reduce inflammation in body tissues. (39-40) Studies in humans with osteoarthritis in the knee have reported some beneficial effects in mobility and pain management. (41-42) A non-placebo-controlled study demonstrated a reduction in clinical signs of naturally occurring osteoarthritis in dogs supplemented with an oral BSE formulation.(43) Another study evaluated two BSE containing supplements compared to placebo in a random, controlled clinical study of 32 client owned dogs with osteoarthritis. This study demonstrated an improvement in clinical signs.(44) These studies in osteoarthritis as well as other studies in other chronic disease states demonstrate BSE can have some efficacy,  seems safe, and well tolerated. (44-47)

Practitioners should be recommending appropriate diets for puppies at risk of developmental orthopedic disease, ensuring they grow slowly and maintain an appropriate body condition score. For joint health for pets, especially overweight dogs with osteoarthritis, even a small amount of weight loss can make an impact on quality of life. Joint support supplements with common ingredients such as EPA, DHA, glucosamine, chondroitin, and newer ingredients such as the New Zealand green lipped mussel (Perna canaliculus) and Boswellia serrata extracts may also benefit dogs with osteoarthritis.