Arthritis is a common condition in dogs and cats (and yes, cats do get arthritis — they’re just better at hiding it!). Osteoarthritis is a degenerative condition of the joints that causes stiffness, loss of mobility and discomfort.
In the early stages, arthritis causes inflammation in the joints. An unfortunate consequence is that new bone is laid down.
This remodels the joint, but not for the better — new bone deposits get in the way of movement and restrict how far the joint can bend and flex.
Typically, the first signs of arthritis are stiffness when getting up after a long rest, such as first thing in the morning after a night’s sleep. You may notice this when your pet stretches in a tentative manner and takes stiff, stilted steps when he first rises.
In the early stages, this stiffness eases within a few minutes as he gets moving and the joints warm up. In more advanced cases, either pain or physical changes in the joints mean the stiffness becomes permanent.
Other signs include long-term lameness or limping on a particular leg. The affected joint(s) may be bigger than the same joint on the other leg and may feel hot to the touch. Some pets lick at a sore joint in an attempt to ease the aching discomfort. A giveaway clue of this is if your white-coated pet has brown saliva staining a joint.
The initial inflammation that is the start of arthritis often happens because of damage to the joint where bone rubs against bone. This could be because of an accident in earlier life or as part of the aging process, where the joint lining cracks and chips.
Joint surfaces are meant to move smoothly over one another. Slippery fluid lubricates the joint, and the joint surfaces are lined with smooth cartilage so the bones slide over one another without catching or knocking.
When damage occurs to the cartilage lining or the amount of joint fluid decreases, bone rubs against bone, causing inflammation that makes arthritis painful. In an attempt to repair itself, new bony spurs are laid down, but this limits the range of joint movement and results in permanent stiffness.
The history of long-term stiffness, which gets steadily worse, is a clue to arthritis, although other conditions can also cause similar signs. To reach a diagnosis, your veterinarian watches your dog or cat walking and examines each limb, looking for telltale signs of pain, heat or swelling of the joints.
To confirm the suspicion and to rule out other problems, such as a joint infection or cancer, the next step is to take radiographs of the sore joints to look for changes associated with osteoarthritis. Based on those results, it may be necessary to take a sample of joint fluid to look for bacteria and rule out infection.
The mainstay of arthritis treatment is pain relief, of which drugs most commonly used belong to the non-steroidal anti-inflammatory drugs (NSAIDs). These are effective and have a high safety margin, although — like any medication — side effects may occur in some individuals.
Opinions vary about the use of neutraceuticals (food supplements), such as chondroitin and glucosamine (affiliate link). The theory is that they provide the joints with the building blocks of repair, but researchers point out that the molecules are too large to filter into the joints where they are needed.
Where possible, encourage your arthritic pet to exercise, albeit gently. This helps keep the muscles toned, which support the joints.
However, never over-exert the pet — if the muscles become over-tired, they offer little support, and the arthritic joint is likely to be damaged even more.
X-rays can show how pets’ joints develop arthritis, as seen in this video:
It is crucial to keep an arthritic pet slim and trim. Carrying extra weight places more strain on those struggling joints, which causes more pain.
Overweight animals are also less likely to move around, which leads to muscle wastage and further loss of support to those sore joints.
- “Non-steroidal anti-inflammatory drugs and corticosteroids for the management of canine osteoarthritis.” Johnston & Budsberg. Vet Clin North Am Small Anim Pract, 27: 841–862.
- “Pathophysiology of osteoarthritis.” Martel-Pelletier. Osteoarthritis Cartilage, 6(6): 374–376.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Oct. 11, 2018.