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(207) 846-6515 H

(207) 846-6515



Osteoarthritis is inflammation and progressive deterioration of a joint or joints. It is sometimes also called arthritis, degenerative joint disease (DJD), and, if it occurs in the spine, spondylosis.

Osteoarthritis (OA) in dogs is a common and complex problem. Simultaneous degenerative and repair processes occur in the affected joints, and secondary inflammation provokes more degeneration and repair, creating a vicious cycle. Unfortunately, the repair processes are not helpful. The patient’s body deposits new bone (osteophytes) along and around the joint surfaces in an attempt to create a new, stable joint surface. But this new bone does not stabilize the joint. Instead, it just inflames it further. The joint capsule (the heavy fibrous sleeve of the joint) thickens, decreasing the patient’s range of motion. Ultimately weakness and pain are the end results of these changes.


Osteoarthritis is inflammation and progressive deterioration of a joint or joints. It is sometimes also called arthritis, degenerative joint disease, and, if it occurs in the spine, spondylosis.

There are two basic types of OA, primary and secondary. Primary OA occurs when normal stresses (for example, walking, running) act upon abnormal joint tissues.

Secondary OA occurs when abnormal stresses (for example, excessive athletic activity, trauma) act upon normal joint tissues, or as a consequence of another recognizable joint problem (infection, immune-mediated disease, hip dysplasia, elbow dysplasia, cruciate disease, osteochondrosis, etc.). Secondary OA is much more common than primary, and, in our practice, cruciate disease is the single most common cause of secondary OA.

Some of the problems that lead to secondary OA have established or suspected genetic components (eg, hip dysplasia, cruciate disease), and genetic factors indirectly and directly play a role in the progress of both secondary and primary OA.

Once they begin both primary and secondary OA progress in the same way.


Osteoarthritis is, therefore, a progressive problem. For individual patients the speed at which OA progresses varies over time for a number of reasons, some of which are diagnosable and manageable, and some of which are not. For example, the progress of OA in an obese patient is faster than it is in a patient with a relatively lean body weight. If the obese patient loses weight the progress of OA slows down. In subsequent articles we will consider the various treatment options but it is important to note here that there is no treatment option that will stop OA dead in its tracks or reverse it. We can significantly help most patients with OA, but we can never cure them.


The degeneration and inflammation of OA always results in three things:

  • joint stiffness - loss of flexibility

  • limitation of the range of motion of affected joints

  • pain

We have found that many owners of dogs with OA, including even the most alert owners, fail to appreciate that the third item - pain - always accompanies the first two. If a dog with OA cannot hop into the car, or is slow to rise from lying down, or cannot go for as long as walk as it used to, it is never just stiff or lacking range of motion; it is also in pain.

This last point has great implications for how we design our treatment protocols for OA patients. Many of the treatments are primarily targeted at relieving stiffness and improving the range of motion, but they are of no value at all if we do not simultaneously use medicine to effectively manage the patient’s pain.

Peter Smith, DVM

Yarmouth Veterinary Center


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