One in five dogs over the age of 1 year has osteoarthritis. It’s also the number 1 cause of chronic pain in dogs
What is osteoarthritis?
Put 'osteo' (bone), 'arthro' (joint) and 'itis' (inflammation) together and you get osteoarthritis (OA), a term that describes a form of chronic joint inflammation caused by deterioration of joint cartilage and the underlying bone. Because of this, it's often also called degenerative joint disease (DJD).
Mostly, we just call it arthritis.
There are two main types of OA: primary, which has no underlying cause (rare in dogs, possibly common in cats); and secondary, which occurs because of something else such as abnormal wear on normal cartilage due to injury. The wearing of the cartilage causes persistent inflammation, which in turn, causes sensitisation of pain receptors and pain pathways.... and chronic pain.
Osteoarthritis can range in severity from a mild, intermittent condition causing slight discomfort to an advanced clinical state characterised by constant pain and severe disability.
What causes arthritis?
Common causes in dogs include:
abnormal development of the hip (hip dysplasia) or elbow (elbow dysplasia)
abnormal development of bone and cartilage that results in a loose flap of cartilage within the joint (called osteochondrosis dissecans or OCD)
dislocation of the kneecap (called patella luxation)
congenital shoulder dislocation (called shoulder luxation)
necrosis (death) of the tissue of the ball of the hip joint (known as Legg-Calve-Perthes disease)
There are several factors that increase the risk of developing arthritis. Genetics play a big role, for example, conditions such as hip dysplasia, patella luxation and cruciate rupture occur much more commonly in certain breeds. Obesity is another risk factor as it places more stress on joints, as does some athletic activity (eg frisbee/ball chasing, racing in Greyhounds).
Medical conditions and treatments that affect collagen or cartilage also increase the risk of arthritis. These include Cushing's disease (hyperadrenocorticism), diabetes, hypothyroidism and prolonged treatment with corticosteroids.
What are the signs of arthritis?
In dogs, the main signs of OA are:
decreased activity levels
unwillingness to do certain things like jumping into the car, going up or down stairs
intermittent lameness or stiff gait that slowly progresses
lagging behind on walks
difficulty in rising from rest
lameness or abnormal gait that may become worse with exercise, long periods of lying down or resting and/or cold weather
stiff-legged or altered gait such as bunny hopping in hip dysplasia
soreness when touched
withdrawn or aggressive behaviour
Not every dog will have all signs. Surprising to most people, dogs with arthritis don't tend to yelp or whine. Making distressed noises is more common with acute pain than with chronic pain syndromes.
How is arthritis diagnosed?
Arthritis is mainly diagnosed on history and physical examination. In the history, we're looking at age, signs (as above) and previous reports of injury/trauma.
On physical examination, we're looking for:
visible joint deformity
decreased range of motion of the affected joint
grating detected with joint movement (known as crepitus)
increased fluid in the joint (effusion)
thickened joint capsule
We make suggest taking some X-rays. These help rule of other causes of joint pain and assess the degree of bony changes in the joint. It should be noted that the severity of changes on X-ray doesn't necessarily match the severity of clinical disease. We may see lots of degenerative change on X-ray but have a cat that's walking around pretty well.
Blood and urine tests are not usually needed to diagnose or investigate arthritis. But we may recommend them if we're concerned about other conditions (eg diabetes) or to check for contraindications before starting medications.
How is arthritis treated?
The goal of OA treatment is to alleviate pain and improve (or maintain) function. There is no cure. We may have to try several different treatments to find what works for your dog. Usually, we'll end up using a combination of the therapies (ie multimodal therapy).
Here are the main treatments.
Keeping mobile is really important. Lack of use of affected joints will cause surrounding muscles to weaken and ligaments and tendons to stiffen, which just makes things worse.
Walking and swimming are great options. How much exercise depends on your dog's situation. It should be done regularly (preferably daily) but you want to limit the amount activity to a level that minimises aggravation of symptoms.
It can be very helpful to see a physio who can tailor an exercise program for your dog. We recommend Dogs in Motion, who also do hydrotherapy, which is great non-weight bearing exercise (for dogs that don't hate water!)
If your dog is overweight, try and get some weight off to reduce stress on joints. This may just mean feeding less of what you're feeding now or trying a different food. Just about every pet food manufacturer makes a 'light' version of their food. We stock the Hill's® and Royal Canin® veterinary prescription diets, but there are plenty of different options. If you'd like to make your own, it's worth having a look at BalanceIT®, which can help you make sure you're getting the nutrients right.
There are also special 'joint diets' such as Royal Canin® Mobility C2P+ and Hill's Science Diet® J/D. These contain supplements that may reduce inflammation and support/protect joint cartilage. Most supplements can be purchased separately if preferred.
There are lots available. Not all of them have scientific evidence of benefit (or at least not yet). Here are some that do:
omega 3 fatty acids found in fish oils (docosahexaenoic acid or DHA and eicosapentaenoic acid or EPA) – these have been found to reduce production of inflammatory chemicals and help with the symptoms of OA in dogs. Their evidence of benefit in people with OA is less clear, but they do seem to help relieve symptoms of rheumatoid arthritis
green-lipped mussels – there are several products containing green-lipped mussel extracts that have been around for a while but a newer product called Antinol® appears to have some pretty impressive evidence of benefit
chondroitin sulphate and glucosamine – are widely used to slow down the progression of arthritis and protect joint cartilage in people and pets. There is some evidence that they work, but not all products are equal and it can be hard to know if you're getting a high-quality version when it comes to pet products
methylsulfonylmethane (MSM) – this seems to have a positive effect in people with OA (when used in combination with other things), but there isn't much in the way of good evidence in dogs
There are several supplement blends available for pets (eg Glyde®, Paw Osteocare®). Some people swear they help with their pets' arthritis. Some people don't notice much change with their use. They don't appear to cause harm and it's possible that even if you're not seeing things improving, perhaps things aren't progressing either.
Injectable joint protectants
These work like chondroitin and glucosamines – they stimulate cartilage repair and inhibit ongoing damage. The most common one is pentosan, of which there are several different versions. We use one called Zydax® because it has the highest quality evidence. It is given as a course of four injections over 4 weeks. Some dogs do well with regular injections after the initial course.
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs are the most commonly used pain-relieving medications. There are several safe, very effective NSAIDs formulated for veterinary patients (eg meloxicam, carprofen). These drugs are metabolised and excreted by the liver and kidneys, which may be compromised in older dogs, so before we start NSAIDs or if we're using them long term, we may recommend blood and urine testing.
Other pain-relieving medication
In addition to or in place of NSAIDs, we may prescribe pain-relieving medications such as amantadine, tramadol and gabapentin. We don't prescribe opioids for chronic conditions such as OA.
There are now multiple studies showing that acupuncture can reduce pain and improve the quality of life in dogs with various musculoskeletal conditions, including OA. It can be a good option for dogs that have conditions (eg kidney disease) that prevent us using NSAIDS.
Newer therapies: stem cells and platelet rich plasma
There are some general practices offering these sorts of joint injections. We think these are best done (with the fewest complications) in the specialist setting. They involve harvesting tissue from the patient, manipulating it (under strictly controlled conditions) to extract cells and then injecting those cells into the affected joints.
While people often have joint replacement surgery for arthritis, we rarely perform it in dogs. When we do, it's usually to fix the underlying cause of OA such as patella luxation or cranial cruciate ligament rupture.