One of the most common conditions encountered in practice is arthritis, otherwise known as osteoarthritis, or degenerative joint disease (DJD). It may be underdiagnosed because many owners may see their older dogs ‘slowing down’ or ‘becoming stiff’ and consider it part of getting old. It’s often only picked up at routine examinations, such as during vaccinations. While common (thought to affect 20% of adult dogs) it is not normal and can significantly impair our ageing pets’ quality of life.
While dogs are the main topic here, cats also suffer arthritis, although they tend not to appear stiff or sore because of their evolutionary tendency to hide pain. In one study, evidence of DJD was seen on X-rays in up to 90% of cats, with 50% of them having clinical signs of impairment due to joint pain.
What exactly is DJD?
It’s where the function of a joint is reduced due to deterioration of the ‘shock absorber’ articular cartilage. Once damaged, it has limited ability to repair. There is little nerve supply to the cartilage so pain is often not felt early on. The pet continues to weight-bear on the leg, creating more damage. This leads to the creation and remodelling of bone around the joint, thickening of surrounding soft tissues, and pain. Inflammation within the joint triggers further destructive changes so the cycle leading to non-reversible changes continues.
Why do our pets get this?
The cause of the initial damage is often unknown. It may simply be wear and tear of a normal joint, most common in humans and maybe cats. In dogs it’s more likely to be due to abnormal loading of a normal joint from obesity or excessive stop-start type exercise as a young dog, or normal loading of an abnormal joint arising from developmental problems in certain popular breeds. For example, Labradors are prone to hip abnormalities (dysplasia) leading to uneven loading within the joint and eventually arthritic changes. Breeds with bowed legs will also bear weight unevenly through certain joints. An overweight Labrador, for example, could suffer the double whammy of abnormal weight bearing through an abnormal joint.
What are the signs?
As alluded to, dogs may be stiff or sore, especially after rest or excessive exercise. However, signs can be more subtle including: reluctance to go for walks, being slow on walks, avoiding stairs/steps, struggling to do things they used to find easy like getting in the car, being more grumpy, showing aggression if you touch a sore spot, and licking a sore joint to the point of making the skin red and sore.
Cats usually show subtle behavioural changes such as: aggression, hiding, sleeping more, reluctance to jump, reduced grooming, reduced playing/hunting, and reduced interaction.
Your vet may be able to feel changes in the joint, if severe, or feel a reduced range of movement and pain. This, alongside your pet’s age, may be enough for a tentative diagnosis. If in doubt, x-rays may be advised, although the (small) risk of anaesthetic must be considered.
Can anything be done?
There’s been huge amounts of research in both human and veterinary fields, but no way to halt this progressive disease process has been found. It’s not all doom and gloom, however. Although your pet will never be ‘cured’ there are ways to slow the progression and ease the signs. It’s important to attack this problem from many angles and, as all our pets are individuals, there’s no one-size-fits-all plan.
There’s a wealth of treatments on the market, some not as proven as others (for effectiveness but also safety). Always talk to your vet before implementing any treatments.
We normally start with what some vets call the ‘holy trinity’ of management.
- Weight management. It is estimated that around 60% of dogs in the UK are overweight. Simple mechanics mean a dog weighing 20kg that should weigh 15kg will place 33% more force through each limb. Aim for the lowest healthy body weight. This can be hard to achieve when exercise is limited, but your vet practice can support you with diet advice. Even a small weight reduction can make a huge difference to signs and quality of life. When considering diet there is some evidence that a diet with a high ratio of omega 3:omega 6 fatty acids in the diet (or as a supplement) may improve signs of DJD.
- Exercise. Depending on how severe your dog’s arthritis is, your vet may recommend they be walked on the lead, as we know stop-start chasing movements stress joints more. As the disease progresses, walks should be short and frequent. If long, rambling walks with a dog are your thing, this lifestyle change can be hard to come to terms with. Hydrotherapy offers a lower risk exercise route.
- Pain relief. Non-steroidal anti-inflammatories (NSAIDs) are the mainstay of pain relief for pets with DJD. Although there are risks and side effects with every medication, these medications are well tested and effective and can vastly improve an arthritic pet’s quality of life. Your vet can discuss the pros and cons with you. Additional pain killing medications can be added in but as none are licensed for this condition, and many have a weak evidence base, these should only really be used when the tried and tested methods have failed or can’t be used, and after discussion with your vet.
Surgery for joint replacement may be recommended in some situations but the cost and risks can be prohibitive.
Some vets use injections of pentosan polysulfate sodium which is marketed to preserve joint health. New treatments such as injection of joints with platelet-rich plasma, or stem cells are available, but it is early days for these treatments and more evidence is needed.
Nutraceuticals such as chondroitin and glucosamine, turmeric extract, and treatments such as acupuncture, shockwave therapy and low-level laser light therapy are also available out there. They are low risk risk but little supporting evidence exists as yet, so your money and time may be best spent elsewhere first.