By: Sherman O. Canapp Jr., DVM, MS, CCRT, and Lisa M. Fair, VT, CCRA, CMT

Osteoarthritis (OA) is the most common joint disease in dogs. It is reported that one in every five dogs greater than a year old is affected. Incidents increase as dogs age with one in every two dogs ten years or older affected.

Multiple etiologies are suspected to contribute to the formation of OA, including congenital and developmental abnormalities, joint instability, joint trauma, defective articular cartilage structure and biosynthesis, and inflammatory conditions. In our experience, congenital and developmental abnormalities and joint instability are the leading cause of OA.

Early intervention offers the best prognosis for minimizing OA. Early intervention includes screening for developmental orthopedic diseases, especially in breeds with known risk, and thorough investigation of seemingly indistinct clinical signs in young dogs. Too often presenting complaints such as slow moving, clumsy gait, less playful or lazy and even intermittent lameness are attributed to "growing pains" when in reality these are often early signs of underlying joint disease. This is the most often missed opportunity for early identification and treatment of joint diseases that could have a profound impact on the dog's longevity and quality of life.

In some cases an orthopedic examination and radiographs can provide diagnosis (i.e. hip dysplasia), however more advanced diagnostics such as CT, MRI or arthroscopy may be needed (i.e fragmented coronoid processes (FCP) of the elbow may not be evident on routine radiographs). Depending on findings, surgical intervention may be warranted. Early intervention is also imperative for traumatic injuries including those that leave joints unstable. This can include cruciate ligament insufficiency, traumatic FCP, medial shoulder syndrome/instability (MSS/MSI) and carpal and tarsal sprain/ strain injuries. Although these injures can occur acutely, joint instability can also result from repetitive activities and these types of injuries are common in sporting and working dogs. Early and appropriate management of these injuries can greatly reduce development and advancement of OA.

Regardless of whether surgical or conservative management is pursued, a complete management program should be multifaceted. 

Components of a comprehensive program may include: * Diet, nutrition and supplements * Weight management and exercise * Assistive devices * Acupuncture and physical manipulation (chiropractic) * Regenerative medicine therapy * Rehabilitation therapy * NSAIDs and adjunct medications * Disease modifying agents and corticosteriods

The role of diet and supplements

Diet and nutrition have significant impact on health and disease. Nutrition has been shown to play a role in developmental skeletal disease. An excess of specific nutrients can exacerbate musculoskeletal disorders, and fast-growing, large breed puppies are at particular risk. For these dogs, controlled growth, optimum levels of calcium and phosphorus and essential fatty acids as well as specific natural ingredients to enhance development are all essential elements to reduce the risk of developmental skeletal disease. In all dogs, providing proper nutrition during growth and maintaining a healthy weight throughout life can help minimize the development of OA.

Beyond providing age-appropriate nutrition, diets that include or are supplemented with certain nutritional factors may reduce inflammation, slow degradation, enhance cartilage repair and provide relief from the associated discomfort.

* Omega 3 fatty acids are essential fatty acids. Two components of Omega 3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, better known as EPA and DHA, found in cold water fi sh have been shown to reduce inflammation and reduce pain associated with OA. EPA specifically has been shown to suppress the degradative enzymens associated with cartilage destruction.

* Glucosamine is a precursor for glycosaminoglycans (GAGS), which are a primary component of joint cartilage. Supplemental glucosamine may influence cartilage structure and restore synovial fluid. GAGs may also aid in the prevention of OA.

* Chondrotin sulfate is an important structural component of cartilage and provides resistance of cartilage to compression. Supplemental chondrotin sulfate may reduce inflammation, stimulate synthesis of proteoglycans and hyaluronic acid as well as decrease catabolic activity.

* ASU (avocado/soybean unsaponifiables) has been demonstrated to help protect cartilage from degradation. Studies have shown a synergy when glucosamine hydrochloride, chondrotin sulfate and AUS are combined. Together they provide improved inhibition in expression of agents involved in cartilage breakdown.

* MSM (methylsulfonylmethane) is an organosulfur compound and although the biochemical effects of supplemental MSM are poorly understood, some research has suggested that MSM has anti-inflammatory effects. Research suggests there may be increased benefit when it is combined with glucosamine and chondrotin.

* SAM-e (S-Adenosyl methionine) is naturally made by the body and plays an important role in normal bodily functions. Often used as a supplement for liver support, studies have demonstrated that supplemental SAM-e can also reduce discomfort associated with OA. Some studies even found SAM-e to be as effective for relieving pain as NSAIDs.

* Vitamin E is the primary lipid-soluble antioxidant present in plasma, erythrocytes and tissues. Oxidative damage to essential cell components caused by oxygen free radicals is a mechanism in the pathobiology of degenerative joint disease. Vitamin E inhibits lipid oxidation. Research indicates that levels of Vitamin E must be higher than minimal requirements to achieve biologic benefits. Further, supplementation with Vitamin E is needed when supplementing with fatty acids as these fatty acids can deplete Vitamin E in the body.

* Vitamin C (ascorbic acid) is an essential nutrient well known for its antioxidant activity. Although dogs can synthesize enough vitamin C to meet minimal requirements, supplementation may improve antioxidant performance. However, it is important to note that vitamin C supplementation can contribute to calcium oxalate crystal formation in susceptible dogs. In addition, over supplementation can cause loose stools.

* DLPA (DL-phenylalanine) is a natural amino acid used to treat chronic pain. DLPA inhibits several enzymes that are responsible for the destruction of endorphins. Endorphins are pain-killing hormones and by inhibiting their destruction, pain relief is prolonged. It can also potentiate opiate analgesia and prolong the effects of acupuncture. DLPA can be used as an alternative to NSAIDs. DLPA cannot be used with any MAOI drugs such as Anipryl (used for treatment of Pituitary-Dependent Hyperadrenocorticism (PDH)/Cushing's Disease and Canine Cognitive Dysfunction) or Amitraz (used in tick collars).

* Traumeel is a homeopathic formulation of 12 botanical substances and one mineral substance. It has been diluted beyond the molecular level, probably with nonoparticle effects as the MOA. It is purported to have anti-inflammatory, anti-edematous and anti-exudative properties. Although the exact mechanism of action is not well understood, it appears to be the result of modulation of the release of oxygen radicals from activated neutrophils, and inhibition of the release of inflammatory mediators (possibly interleukin-1 from activated macrophages) and neuropeptides (2). Traumeel is often used as an alternative to NSAIDs.

* GLM (Green-Lipped Mussels) has been shown to contain anti-inflammatory components and other nutrients that may benefit joint health. Exact mechanisms of action are unknown, however, clinical studies of GLM powder added to diets either by way of incorporating into food using low-temperature processing (heat processing of GLM has been shown to destroy its activity) or sprinkling on top of food showed GLM to be effective in reducing symptoms.

* Herbs - There are several herbs that have anti-inflammatory and analgesic properties, as well as various herbal formulations purported to aid dogs suffering with OA. Commonly used herbs include: * Boswellia * Yucca root * Turmeric * Hawthorn * Nettle leaf * Licorice * Meadowsweet * Willow bark

It is important to note that herbs can have side effects as with any drug. In addition, herbs may have interactions with other herbs, supplements and medications. Consultation with a qualified botanical medicine professional can be beneficial in determining which herbs and at what doses those herbs can offer benefit to your pet.

When considering supplementation, it is important to consider the whole dog and any concurrent diseases or conditions. Many dogs being treated for OA are geriatric and may have impaired organ function. Prior to adding any supplementation, especially in the geriatric dog, a physical examination, baseline urinalysis, complete blood count and blood chemistry is recommended. Research potential contraindications, drug interactions and appropriate dosing of any supplement considered prior to administration. Many dog foods formulated specifically for OA contain several of these supplements; therefore additional supplementation may require dosing adjustments.

Weight management and exercise

Obesity is a known risk factor for OA in dogs. Owners must be educated on the importance of maintaining their dogs at a healthy weight and each visit should include evaluation of weight and body condition score (BCS). Dogs with excess weight should be placed on a diet management program, which may include food restriction, change in diet, exercise and behavior modification. As discussed above, many owners give treats without thought to caloric implications. Compliance to weight management programs is often a challenge so be sure to discuss and include treats when formulating weight management programs. Weight management alone may result in significant clinical improvement.

Light to moderate low impact exercise is recommended to reduce stiffness and maintain joint mobility. Specific exercise requirements can vary based on the individual dog, however short walks (15 to 20 minutes) performed two to three times daily are typically recommended. Swimming is an excellent low impact activity that can improve muscle mass and joint range of motion. The most critical aspect is consistency. Exercise should be performed on a routine basis and excessive and/or high impact exercise should be avoided.

Assistive devices

These provide assistance with mobility for walking, rising and maneuvering. Booties can provide traction for slippery surfaces. Orthotics can provide support to joints which can also improve comfort. Slings and harnesses can be used to assist pets when rising, walking, performing stairs and during eliminations. Carts can provide independent mobility for dogs that have difficulty walking.

Canine osteoarthritis is an incurable condition, however, with early intervention, when possible, and a multimodal approach we can extend the longevity and quality of life for our canine companions.