Dog Osteoarthritis Explained: What Causes It, How to Spot It, and What You Can Actually Do

Roughly one in five adult dogs has osteoarthritis. By the time they hit eight, that number climbs closer to four out of five. And here is the part most owners do not realise: a meaningful share of dogs living with osteoarthritis are never formally diagnosed by a vet. They get labelled "slowing down" or "just getting old", and they live with daily joint pain that they cannot tell anyone about.

This article is for the owner who has noticed something is off, or who wants to get ahead of a problem before it becomes one. We will cover what osteoarthritis is, how to spot it early, what your vet can actually do, and what changes the long-term trajectory more than most owners realise.

What is osteoarthritis, really?

Osteoarthritis (OA) is a progressive joint disease. Three things happen inside an affected joint, and they feed each other.

First, the cartilage that cushions the bone ends starts to break down. Cartilage has no nerve supply and no blood supply, so it cannot heal itself the way other tissues can. Once it starts wearing thin, the damage tends to accumulate.

Second, the synovial membrane (the inner lining of the joint) becomes inflamed. This is what produces a lot of the chronic pain. The inflammation also releases chemical signals that make the cartilage damage worse over time.

Third, the bone underneath the cartilage starts to remodel. Small bony outgrowths called osteophytes form around the edges of the joint, and the bone surface beneath the worn cartilage thickens. These changes are what shows up on X-rays.

Two important corrections to common assumptions.

OA is not a natural part of ageing. A lot of older dogs have it because they have had years for joint wear to accumulate, but plenty of senior dogs do not develop OA, and plenty of younger dogs do. Treating it as inevitable means letting a treatable condition progress further than it has to.

It is much more common than diagnosed numbers suggest. A 2018 UK primary care study published in Scientific Reports, drawing on the VetCompass database of nearly half a million dogs, found that formally diagnosed canine OA in general practice was only a small percentage of the total. Radiographic studies have found OA evidence in around 80 per cent of dogs over eight years old. The gap between "diagnosed" and "actually has it" is enormous, and that gap is the single biggest reason owners come to this article in the first place.

How to spot it: the symptoms

The frustrating thing about osteoarthritis is that the early signs do not look like pain. They look like a slightly slower, slightly less interested dog.

The earliest things to watch for are behavioural, not physical:

• Hesitating before jumping onto the bed or couch
• Slower to stand up after lying down
• Stiffness for the first few minutes of a walk, then loosening up
• Choosing the shorter route on walks
• Less interested in stairs, especially going up
• Sleeping more, playing less
• A bit grumpier than usual, particularly when touched on the back or hips
• Stopping the usual grooming routine (a dog with sore joints stops cleaning paws or licking certain spots)

These signs are easy to miss because they are gradual. They drift in over months. Owners attribute the change to age, and the dog adapts to compensate, which makes detection even harder.

The more obvious signs appear later:

• Visible limping, especially after rest
• Difficulty getting up from a lying position
• Visible muscle loss on the back legs or shoulders
• Trembling in the hind legs after exercise
• Yelping when getting up or being lifted
• Reluctance to walk on smooth floors (because slipping hurts)

A useful exercise: think about what your dog could do easily a year ago. Walking longer, jumping more confidently, lasting through longer play. If you notice even small drops in those everyday things, it is worth a vet visit.

A practical step is video. Phone-record a thirty-second clip of your dog getting up from rest, walking on a flat surface, and doing one set of stairs. Keep them on file. If you have to make a case to the vet six months later, you will have evidence of change rather than memory of change.

The 2024 review by Pye and colleagues in the Journal of Small Animal Practice noted that early identification of mobility decline is one of the biggest open challenges in primary care, partly because owners and vets both underestimate it.

What causes it

There are two broad ways a dog ends up with OA.

Primary OA is when genetics and joint structure mean the joints are predisposed to wear faster than they should. This is most common in dogs with breed-related hip or elbow dysplasia.

Large breeds carry the highest baseline risk: data from the Orthopedic Foundation for Animals (OFA) puts hip dysplasia rates around 22 per cent in German shepherds, 20 per cent in golden retrievers, and 12 per cent in Labradors, with much higher rates in some giant breeds. For these dogs, the underlying joint anatomy means OA can show up much earlier than the typical senior years.

Secondary OA is when a specific event or condition triggers joint damage that then progresses to arthritis. Common causes:

• Cranial cruciate ligament (CCL) injury. A torn CCL, even after surgical repair, often leads to OA in the affected knee within a few years.
• Joint trauma. Fractures, dislocations, or significant impact injuries that involve a joint can trigger OA at that site.
• Obesity. Excess body weight is one of the largest controllable risk factors. Every extra kilogram is daily mechanical load on every joint. Body fat is also metabolically active and contributes to systemic inflammation that worsens joint damage.
• Repetitive high-impact activity without proper conditioning, especially in young or unsupported dogs.
• Other developmental conditions like osteochondritis dissecans (OCD) or patellar luxation.

The honest summary is that osteoarthritis is rarely caused by one thing. Most dogs who develop it have several factors stacked together: genetics, body weight, age, and the inflammatory load that comes with modern indoor life. Identifying which of those you can change is the practical starting point.

How vets diagnose it

A proper diagnosis usually involves three layers.

1. Clinical exam. Your vet will watch your dog walk, palpate the joints (feeling for swelling, warmth, range-of-motion limits), and observe how the dog responds when joints are flexed. An experienced vet can detect mobility changes that imaging cannot.

2. Radiographs (X-rays).This is the standard imaging for OA. Radiographs show osteophytes, narrowed joint space, and bone changes. The honest limitation is that X-ray findings do not match symptom severity well. A dog with mild radiographic changes can be in serious pain, and a dog with dramatic-looking X-rays can be moving comfortably.

3. Modern staging tools. The 2023 international consensus guidelines published by the COAST Development Group in Frontiers in Veterinary Science introduced a clinical staging tool called COASTeR (Canine OsteoArthritis Staging Tool excluding Radiography).

It combines an owner questionnaire, the vet's clinical assessment, and orthopaedic examination to produce a stage (0 to 4) that guides treatment more usefully than X-rays alone. If your vet uses or knows COASTeR staging, that is a good sign that they are practising current best-evidence medicine.

When advanced imaging is needed. CT and MRI are usually reserved for cases where the diagnosis is unclear, or where surgery is being considered and the vet needs to see exactly what is going on inside the joint.

For most dogs, the combination of a thorough clinical exam plus radiographs is enough to make the diagnosis and stage the disease. Diagnostic perfection is not the bottleneck. The bottleneck is owners noticing early enough to bring the dog in.

Treatment: what actually works

There is no cure for osteoarthritis. The treatment goal is to slow progression, manage pain, and keep the dog moving comfortably for as long as possible. The international consensus published by the COAST group in 2023 is that this requires a "multimodal approach": a combination of strategies that each contribute something different. Single-bullet thinking does not work for this disease.

Pharmaceuticals

Non-steroidal anti-inflammatory drugs (NSAIDs) like carprofen and meloxicam are the most common first-line medications. They reduce inflammation and pain effectively for many dogs. The honest trade-off is that long-term use can affect the kidneys, liver, and gastrointestinal system.

A 2013 systematic review by Monteiro-Steagall and colleagues in the Journal of Veterinary Internal Medicine reviewed 64 studies covering 14 different NSAIDs and found adverse effects were detected in 55 per cent of studies, with rates varying widely depending on the population and follow-up. Most dogs tolerate NSAIDs well, but they require periodic blood monitoring on long-term use.

Newer options expanding the toolkit:

Grapiprant is a newer NSAID that targets a more specific inflammation pathway (the EP4 receptor) and tends to have a gentler gastrointestinal profile.

Bedinvetmab (sold as Librela in Australia) is a monoclonal antibody given as a monthly injection. It binds nerve growth factor and reduces pain signalling. The Australian Veterinary Pain Advisory Committee (VPAC) guidelines, sponsored by Zoetis (who makes the product), list it as a first-line option for canine OA pain.

Gabapentin is often added for chronic pain that is not fully controlled by NSAIDs alone.

Pentosan polysulfate injections (Cartrophen in Australia) are disease-modifying agents that support joint metabolism. Given as a course of injections rather than daily medication.

Your vet will choose based on your dog's COASTeR stage, any other health conditions they have, and what you can realistically spend long-term.

Nutritional and supplement support

The 2024 Pye review in the Journal of Small Animal Practice looked across the non-pharmaceutical evidence for canine OA and identified a small number of supplement ingredients with reasonable canine clinical data: green-lipped mussel, omega-3 fatty acids (especially marine sources), and undenatured Type II collagen combined with Boswellia.

Green-lipped mussel has the strongest published canine evidence base. A 2009 randomised double-blind trial published in Evidence-Based Complementary and Alternative Medicine found dogs on green-lipped mussel showed statistically significant improvements in mobility (P=0.012) and owner-reported pain (P=0.004) over placebo. Earlier work in the Journal of Nutrition in 2002 reached the same direction of conclusion.

The COAST 2023 guidelines explicitly recommend nutraceutical support as part of the "foundational base" applicable across all OA stages, alongside weight management, exercise, and rehabilitation. The point is not that one supplement fixes anything. The point is that consistent daily nutritional support is one of several inputs that, together, change the long-term trajectory.

Surgical options

For severe cases, surgery is sometimes the right call. Options include arthroscopic joint debridement, joint stabilisation procedures, and (in extreme hip cases) total hip replacement. Surgery is usually reserved for younger dogs with structural issues or for older dogs whose pain is no longer controllable with medication and supportive care.

At-home support: the ordinary things that matter most

This is the part most owners skim and the part that has the largest long-term impact. The ordinary daily things matter more than the impressive drugs.

1. Weight management. This is the single biggest lever. The COAST 2023 international consensus lists weight management as foundational at every OA stage, including stage zero (no OA yet). If your dog is overweight, the most important thing you can do is fix that. Talk to your vet about a realistic weight-loss plan.

2. Controlled exercise. Movement is good. Pounding the pavement is not. The right kind of exercise for an OA-prone dog is regular, low-impact, and consistent:

- Short, frequent walks rather than one long weekend session
- Swimming (formal hydrotherapy is excellent if available)
- Walking on grass or sand rather than concrete
- Avoiding sudden direction changes (sharp-turn fetch games are hard on knees)

3. Environmental modifications. mall home changes have outsized impact:

- Non-slip flooring or runners on slippery surfaces (slipping hurts arthritic joints and increases injury risk)
- A ramp or low steps for getting onto the bed or into the car
- A supportive bed (orthopaedic foam or memory foam helps; thin mattresses do not)
- Raised food and water bowls so the dog does not bend down to eat
- Keeping the house warm in winter

4. Physical rehabilitation. Veterinary physiotherapy, hydrotherapy, and structured rehab exercises have growing evidence behind them. The Pye 2024 review highlighted physiotherapy and hydrotherapy as among the strongest non-pharmaceutical interventions available. If you have a rehab vet in your area, it is worth the visit, especially early in the disease.

5. Daily nutritional support. Joint supplements, omega-3 fatty acids, and a high-quality diet contribute steady, low-key support. 

The boring stuff carries the long game.

Can osteoarthritis be prevented?

The honest answer is: not fully, but the trajectory can absolutely be changed.

For genetically predisposed breeds, OA risk is partly baked into the structure. A Labrador with hip dysplasia and a sedentary lifestyle will likely develop OA. A Labrador with hip dysplasia who maintains a lean body weight, has consistent low-impact exercise, and starts joint nutritional support before symptoms appear will likely develop less severe OA, and develop it later. Both end up with OA. Only one ends up severely affected.

For young dogs (especially large breeds):

- Start joint nutritional support between 12 and 18 months of age. This is where the most evidence-backed prevention happens. The OFA breed data showing 22 per cent hip dysplasia in German shepherds, 20 per cent in golden retrievers, and 12 per cent in Labradors is reason enough to take preventive action seriously.
- Keep them lean from puppyhood onward. Overweight puppies become arthritic adults.
- Avoid forced repetitive impact (long jogging sessions, agility competition for young dogs) before skeletal maturity.

For all dogs, regardless of breed:

- Lean body weight throughout life is the single most powerful preventive lever
- Regular consistent activity rather than weekend-warrior patterns
- Periodic vet checks, especially after age six
- Quick action on injuries (a soft-tissue strain ignored becomes a chronic problem)

Prevention is not glamorous. It is the quiet daily things done consistently. That is also why it works.

About My Little Tails

My Little Tails started because of a corgi named Kiki, who was diagnosed with congenital hip dysplasia at just eighteen months old. Surgery was considered too risky at her age, so we went looking for something gentler. The search led to New Zealand green-lipped mussel and krill oil. It did not cure Kiki, but it made a real difference. Her condition stabilised, her mobility improved, and she was able to enjoy daily life without surgery. That story became this brand.

For joint support specifically, we make three products:

Mega Mussel : concentrated single-ingredient capsules. 90 per bottle, each a 28:1 New Zealand green-lipped mussel extract (equivalent to 19,000 mg fresh GLM per serve) plus freeze-dried rosemary. For dogs with diagnosed OA, post-surgery recovery, large breeds, and seniors.

My Little Mussels : daily meal-topper. 120 g loose powder of green-lipped mussel, organic turmeric, and shark cartilage. Sprinkled on food, dosed by body weight. For younger dogs and preventive use.

Mega Krill: omega-3 for joint inflammation. 60 softgel capsules of Antarctic krill oil with naturally occurring astaxanthin. Often added alongside Mega Mussel for dogs with diagnosed arthritis.

References

Anderson, K. L., O'Neill, D. G., Brodbelt, D. C., Church, D. B., Meeson, R. L., Sargan, D., Summers, J. F., Zulch, H., & Collins, L. M. (2018). Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care. Scientific Reports, 8(1), 5641. https://www.nature.com/articles/s41598-018-23940-z

Bierer, T. L., & Bui, L. M. (2002). Improvement of arthritic signs in dogs fed green-lipped mussel (*Perna canaliculus*). Journal of Nutrition, 132(6 Suppl), 1634S-1636S. https://pubmed.ncbi.nlm.nih.gov/12042487/

Cachon, T., Frykman, O., Innes, J. F., Lascelles, B. D. X., Okumura, M., Sousa, P., Staffieri, F., Steagall, P. V., & Van Ryssen, B. (2023). COAST Development Group's international consensus guidelines for the treatment of canine osteoarthritis. Frontiers in Veterinary Science. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2023.1137888/full

Hielm-Björkman, A., Tulamo, R. M., Salonen, H., & Raekallio, M. (2009). Evaluating complementary therapies for canine osteoarthritis Part I: Green-lipped mussel (Perna canaliculus). Evidence-Based Complementary and Alternative Medicine, 6(3), 365-373. https://pubmed.ncbi.nlm.nih.gov/18955269/

Monteiro-Steagall, B. P., Steagall, P. V., & Lascelles, B. D. X. (2013). Systematic review of nonsteroidal anti-inflammatory drug-induced adverse effects in dogs. Journal of Veterinary Internal Medicine, 27(5), 1011-1019. https://onlinelibrary.wiley.com/doi/10.1111/jvim.12127

Pye, C., Clark, N., Bruniges, N., Peffers, M., & Comerford, E. (2024). Current evidence for non-pharmaceutical, non-surgical treatments of canine osteoarthritis. Journal of Small Animal Practice. https://pubmed.ncbi.nlm.nih.gov/37776028/

Orthopedic Foundation for Animals (OFA). Hip dysplasia statistics by breed. https://ofa.org/

Veterinary Pain Advisory Committee (VPAC). Australian Guidelines for OA Pain Management in Companion Animals. (Sponsored by Zoetis.)