Animals – Osteoarthritis in dogs

The colder months of the year are fast approaching and the physical stiffness that we see with osteoarthritis is exacerbated by the cold, as well as prolonged periods of inactivity.

Osteoarthritis is degenerative and is also known as degenerative joint disease (DJD). The degeneration affects all tissues that form the joint: the cartilage, the capsule and the underlying bone. The cartilage shows changes in the metabolism of its cells. These go along with changes in the actual make-up of the cartilage as its protein matrix changes.

The fluid retention in the joint surface is reduced, which in turn leads to the loss of its elasticity. In the end, patches of cartilage disappear and the integrity of the joint surface is lost, the underlying bone becomes sclerotic (hardened) and the joint capsule thickens. All joints of the body can be affected, but it is more obvious in the knees, ankles, elbows and shoulders. Predispositions for the condition range from joint injury to hip and elbow dysplasias (abnormal growth).

Anything that influences the normal structure of the joint will lead to osteoarthritis over time, and the ageing process itself leads to degeneration of the joint tissue. The onset of lameness is gradual and not sudden as with an acute injury. Stiffness when getting up from resting, difficulties with jumping into the car or onto the couch, as well as reluctance to walk up stairs are the most common symptoms. Therapy is aimed at slowing down the degenerative process by reducing inflammation and helping the cartilage to stay healthy for longer. The mainstay to reducing pain and inflammation are NSAIDS, or non-steroidal, ant-inflammatory drugs. These are painkillers that reduce inflammation as well as pain, by blocking specific chemical pathways of the inflammatory process. This markedly improves the animal’s motivation to be active and with it the use of its joints. The cartilage gets compressed and decompressed again, like a sponge which in turn helps its nutrition.

Weight control is another important tool to manage the physiologically appropriate loading of the joint. The diet itself can be enriched with anti-inflammatory nutrients like omega-3 fatty acids or chemicals that are found in the joint cartilage itself, like chondroitin sulphate and glucosamine sulphate. There are a lot of nutraceuticals on the market that claim to have the magic ingredient in the right concentration and the appropriate chemical form. Research on the subject is ongoing, and there are reputable dog food manufacturers that have formulated motility diets that show merit. What is certain, though, is if you do not move, you seize up. Exercise (physiotherapy) and adequate nutrition provide a good way out of this Catch-22.

Olaf Klein, Wellsford Vet Clinic
www.vetsonline.co.nz/wellsfordvet