What is osteoarthritis in dogs and how does it develop?
Osteoarthritis is a disease that affects your dog’s joints. In joints with osteoarthritis, the cartilage, which normally cushions the joint and lets it move freely, is damaged. This damage results in inflammation of the joint and surrounding tissue.
This damage to the cartilage is often a result of wear and tear over time, which is why osteoarthritis is so common in older dogs. However, osteoarthritis can occur at any age and is seen earlier in:
- Dogs born with joint problems such as dysplasia (where the joint is not properly formed)
- Dogs who put a lot of strain through their joints, such as sporting dogs
- Dogs who have had their joints operated on for any reason, or had any other kind of joint trauma
- Larger dogs
The damage is irreversible, and while there are many ways to slow down the progression of osteoarthritis and ease the impact of symptoms, osteoarthritis is an incurable condition that will worsen over time.
What causes osteoarthritis in my dog’s joints?
Osteoarthritis is caused by damage to the cartilage in the joint, which then leads to a cascade of other problems associated with the inflammation resulting from the initial injury.
This cartilage damage can happen at any stage in a dog’s life.
Early-onset osteoarthritis can be diagnosed in dogs, even at the puppy stage. A 2024 study concluded that 40% of dogs aged 8 months to 4 years old have signs of osteoarthritis in at least one joint, which demonstrated the staggering prevalence of arthritis in younger dogs even from puppyhood.
The damage to cartilage, leading to osteoarthritis, can be caused by many things, such as:
- Impact and twisting movements during exercise
- Developmental joint problems (dysplasia)
- Strain on joints from being overweight, or a large breed
- Trauma to the joint or surrounding soft tissue, including having a the area operated on
- Natural wear and tear over time
How common is osteoarthritis in dogs, and which breeds are more prone?
Osteoarthritis is incredibly common in dogs. A recent 2024 study showed that 40% of dogs aged 8 months to 4 years old have osteoarthritis in at least one joint. By age 7-8 this prevalence rises to 80%, meaning that 4 out of 5 older dogs have the condition.
Unfortunately, osteoarthritis is chronically underdiagnosed, with the numbers visiting veterinary clinics and receiving support much lower than the actual number of dogs with the condition. Many owners see their dog as simply ‘slowing down’ as they age, or ‘getting older’, when actually there is a lot that can be done to make dogs with arthritis more comfortable if they have been properly diagnosed.
Larger breed dogs are more likely to develop osteoarthritis earlier in their lives, due to the additional weight through their joints and a higher likelihood of developmental joint disease in these breeds. This is why being overweight is a significant risk factor for all breeds of dog.
Breeds that are commonly diagnosed include rottweilers, Labradors, golden retrievers, German shepherds and springer spaniels, although any dog can develop osteoarthritis.
How does osteoarthritis affect a dog’s mobility and quality of life?
Osteoarthritis leads to problems with mobility and quality of life. As the damaged cartilage fails to cushion the joint adequately, movement becomes stiff and the joint becomes inflamed. This means that it is not simply a cartilage issue; it rapidly becomes a whole joint issue.
As the tissues around the joint stiffen and become painful, your dog may want to exercise less, have a change in how they walk (their gait), and take longer rising after rest.
Changes in their exercise levels and desire to move can lead to changes in muscle mass, with muscles around the affected joint becoming smaller and weaker (atrophy).
As the disease progresses, these changes worsen, meaning your dog will experience more pain and stiffness, and find it harder to do the things that bring them joy. Speaking with your vet and other professionals, such as hydrotherapists and physiotherapists, can help provide many ways to support your dog. Having the right sleep surface can support joints while your dog is resting, and other changes such as making sure they are a healthy weight, and managing their exercise, can be pivotal to maintaining quality of life.
Is osteoarthritis the same as rheumatoid arthritis in dogs?
No, osteoarthritis and rheumatoid arthritis are different conditions in dogs. Osteoarthritis is a degenerative condition where the cartilage in the joint is damaged, leading to inflammation and stiffness. Osteoarthritis is very common, affecting 80% of dogs over 8 years old, and 40% of dogs over 8 months old.
In rheumatoid arthritis the dog’s own immune system attacks their joints, causing inflammation and pain. This is a much rarer condition than osteoarthritis, and is treated using drugs that suppress the immune system.
Can young dogs develop osteoarthritis, or is it only in older dogs?
Yes, younger dogs can, and often do, develop osteoarthritis. In fact, osteoarthritis in younger dogs is heavily underdiagnosed, perhaps because osteoarthritis is perceived as an ‘old age’ disease.
In reality, 40% of dogs aged 8 months to 4 years have osteoarthritis in at least one joint on X-rays, and 25% have osteoarthritis that has progressed to the level of showing clinical signs, such as stiffness or limping.
Therefore, it is important we rethink the idea that osteoarthritis is purely an ‘old dog’ problem, or is only associated with ageing.
What role does cartilage play in dog joint health?
Cartilage is a critical part of joint health. It grows over the ends of bones, creating a low-friction surface so the bones can move freely against each other within articular joints. It is also slightly cushioned, meaning it absorbs some of the impact from actions such as jumping.
Without this cartilage, the ends of the bone are exposed and rub against each other. Fragments of cartilage can also come loose within the joint capsule and cause aggravation, and a lack of cushioning means that bones and joints are more susceptible to injury from shock.
This critical role for cartilage means that damage leads to painful osteoarthritis, which is sadly irreversible. The lack of blood supply to cartilaginous tissue means it repairs very poorly. Therefore, in dogs with cartilage damage, working with your vet and other pet health professionals is the best way to manage their condition and minimise impact on their quality of life.
How does osteoarthritis progress over time in dogs?
Osteoarthritis is a degenerative condition, which means it worsens over time. However, the level of changes within the joint do not always correlate with the severity of the signs your dog displays. While the joint itself will slowly worsen, you may see your dog’s symptoms wax and wane, as your dog experiences more managed periods, and periods where they get flare-ups of the condition.
There are four stages to the development of osteoarthritis:
- Early stage – joint changes without any physical symptoms
- Mild – early symptoms such as slowing down, thinking twice about jumping into the boot of the car, and mild loss of muscle mass start to occur. This is often when diagnosis occurs. Flare-ups can be severe, but your dog can have periods of time with very low impact on their day-to-day life, especially with careful management.
- Moderate – Signs become more constant, with clearer pain behaviours, more obvious muscle loss, reduced range of motion in joints, increased stiffness and much slower exercising alongside reluctance to exercise.
- Severe – Mobility is greatly impaired, and dogs may be unable to exercise, clearly limping, and with a poor quality of life. Dogs at this stage require intensive management for their pain, and euthanasia discussions may be had at this point.
It is important to remember that osteoarthritis is a disease with good and bad days throughout its progression.
What are the primary risk factors for canine osteoarthritis?
The major risk factors for osteoarthritis in dogs are:
- Age – as your dog ages, natural wear and tear on the joint damages cartilage, causing osteoarthritis
- Exercise – The more impact and turning forces that go through your dog’s joints, the more susceptible they are to joint damage, including ligament tears, muscle damage, and joint capsule damage. All these lead to secondary damage to the cartilage, both as a result of the injury itself, and exacerbated in cases where surgical repair was required. Even for dogs who do not suffer a specific injury, high-impact exercise causes microtraumas within the joints, which also predispose the development of osteoarthritis.
- Breed – Larger breed dogs, or breeds more likely to develop developmental joint disease, are both at additional risk of developing osteoarthritis. Certain breeds are more likely to have inherited joint abnormalities (joint dysplasia), and the additional weight through the joints of larger breed dogs also puts more pressure on cartilage.
- Weight – If your dog is overweight, this additional strain on joints can have huge impact on joint health. In fact, for overweight pets, weight loss is a cornerstone of management of osteoarthritis and should be one of the earliest interventions if your dog has been diagnosed.
Can obesity or diet increase my dog’s chances of developing osteoarthritis
Yes, being overweight or obese is a significant risk factor for your dog to develop osteoarthritis. In fact, being even 10% overweight can be enough to influence the incidence, development, progression and management of osteoarthritis in your dog.
Becoming overweight is a common challenge for domesticated dogs, especially in those that are neutered (as calorie requirement drops but diet is often unchanged), in dogs living with children or people with dementia (who may find it more difficult to restrict human food/treats), or in those on higher fat content diets.
Maintaining a healthy body weight for your dog is a really important part of reducing the risk of osteoarthritis developing, and is critical in cases where osteoarthritis has already been diagnosed.
