Pets can suffer from aches and pains in the joints just as we humans do. You may have noticed that your cat may not be quite so enthusiastic about jumping onto the sofa as it once was, or your dog may seem reluctant to be taken for a long walk. This could be due to arthritis, or the more appropriately named degenerative joint disease (DJD).

"DJD is a common problem in dogs and cats, and not necessarily just old pets," says veterinarian Lloyd Kenda, of Valley Veterinary Centre www.valleyvetcentre.com.hk.

Many people, he says, have heard of hip dysplasia in dogs, especially in breeds such as Labradors and golden retrievers, but what they may not realise is that this condition is one of the most common causes of DJD. "Dogs suffering from hip dysplasia are born with the potential for the problem. The hips are malaligned and there is very poor congruity of the two surfaces of the hip joint. When the leg moves, the two surfaces of the joint rub and cause abnormal wear on the cartilage of the joint surface. This causes inflammation and thus pain," he explains.

The more they rub, the more the inflammation progresses. Therefore, arthritis tends to be more of a problem in older animals. However, if the joint malalignment is severe, arthritis can occur even in quite young animals, the vet says. "This is seen commonly in small-breed dogs, such as Pomeranians and chihuahuas, with a condition known as medially luxating patellas. In this case, the knee joint is so malformed that the kneecap slips out of place and the whole knee joint is rotated, thus causing severe DJD in very young dogs."

The most obvious sign of DJD is lameness - the pet does not want to use the affected joints, and there may be cries of pain when a joint is moved. In more mild cases, an astute owner may notice that the animal's gait is a little strange. For example, dogs with mild or early hip DJD tend to sway their rear end as they walk. And cat owners may notice that their pet's coat is looking unkempt, as the cat may have difficulty in stretching and bending to groom itself.

"As vets we are trained to observe subtle changes in an animal's walk, which will often give telltale signs of where the problem is, and there are particular ways to stress the joint to determine any malalignment and laxity," Kenda says. Generally, X-rays are required to diagnose the problem.

If poor joints are detected in young animals before severe DJD develops, surgery is often needed to help realign the joint to reduce the likelihood of DJD developing later. In older animals with severe DJD, Kenda says surgery is needed to alleviate pain and restore normal use to the joint, such as with a total hip replacement.

Other important factors are weight and exercise. Kenda says: "Weight loss is very important to reduce the load on the joints, and gentle, low-impact exercise such as swimming helps to keep the joint moving and strengthens the muscles that support the joint."

If surgery is not an option, medication and management can still be helpful. "Anti-inflammatory medications are very useful to reduce the inflammation and consequently the pain in the joint, but it must be remembered that this is by no means a cure for the problem, but merely reduces the pain and thus makes the pet feel better." He adds that the efficacy of such drugs is constantly being improved while their side effects are being reduced. However, there is a drug that does actually help to repair the joint, by basically rejuvenating the joint capsule and the cartilage lining. "Pentosan is administered as a weekly injection for four weeks. The results are a little unpredictable. However, for the animals that it works well for, it seems to work really well," Kenda says.

Supplements added to the pet's food, usually glycosaminoglycan-based, also have unpredictable results, according to the vet, but, he adds, many owners report that they do help their arthritic pet considerably. "So, if you feel your pet has lost its spring in its step, then get it checked by a vet, as treatment ranging from injections to surgery to food supplements might help." 

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