Animal Joint Care 101: Osteoarthritis

Patty Khuly, DVM
Written by:
Published: April 11, 2010
Animal Joint Care 101: Osteoarthritis

Here’s a dramatic observation for you: I think the  most commonly under-treated disease in canine and feline medicine has got to be osteoarthritis (arthritis for short).

I got to thinking about this after getting a job offer from The Bark. Would I write a 750-word essay on the most commonly misdiagnosed ailments in the dog world?  After researching the subject by polling you, my readers, and compiling a lengthy list of candidates for the top slots, I kept coming back around to arthritis.

Problem is, arthritis is very commonly adequately diagnosed. Hence, it can’t possibly hold sway on my "missed diagnoses" list alongside tough nuts like Addison’s disease. Arthritis does, however, suffer from very poor management. In general, it’s my observation that dogs and cats are inadequately treated — as in, "there’s not much we can do for arthritis."

For that reason this subject deserves at least a couple of posts of lively discussion. In this first entry, I’ll keep it at the 35,000 feet level. After all, you need to know your enemy before you can fight it. In the second post (tomorrow’s) I plan to offer you a thorough prescription — generalized though it’ll have to be since I don’t know most of your pets personally.

So let’s meet our adversary:

Osteoarthritis is a complex process, which any of us lucky to live long enough will inevitably experience. Biologically complicated though it may be, its basics are pretty easy to convey.

Normal joints have ultra-smooth surfaces that accumulate tiny changes over time. These imperfections mar the slippery texture of the surface with bumps, ridges and grooves that result in a grating and grinding motion instead of a gliding one. The body responds to these changes by initiating an inflammatory process, the ultimate goal of which is to stabilize the joints (stable joints may not work well, but at least they don’t hurt, right?). To stabilize the joints the body lays down little bony bits in the joint, which leads to more painful grinding and grating … and lots of stiffening.

The tiny changes that accumulate over time come about for a variety of reasons. In pets, osteoarthritis typically comes down to these five simple factors:

1. Age

Every single one of us is headed there. Like it or not, arthritis is inevitable in normal aging. Each day beyond our prime means more and more of these changes to our joints (microscopic though they may be), until eventually we’ve got more lesions than we can handle without feeling pain or stiffness. In pets, this process is so gradual — and our pets so stoic — that it’s nearly imperceptible to owners who don’t know exactly what to look for. Here are the signs in case you don’t know:

  • He’s slower upon rising. (When you call him maybe he thinks about it for a beat before getting up.)
  • Her exercise intolerance is starting to show. (She gets tired more easily and wants to turn around earlier on your morning walk.)
  • The light and easy spring in his step is missing. (Not sure? Take a look at an old video of him at 1-2 years of age for comparison.)
  • Jumping up to the couch or the counter isn’t something she’s excited about any more. (She may still do it, but not without contemplating it for a second or two.)

Note: Rarely will dogs and cats exhibit obvious pain. If they do, it’s usually because the pain is sudden, or because they’re stressed or frightened. Chronic pain, however, the kind they’ve come to live with over time, is something they’ve already learned to accept.

2. Size

Generally speaking, the larger the pet the worse the arthritis. This is a truism, but it’s important to note that it typically holds true only within a species. In other words, a well-proportioned (non-obese, but undeniably large) fifteen-pound cat is much more likely to get arthritis — especially early on — than a thirty-pound dog.

Though the dog weighs twice what the cat does in this example, the dog is normal for her species. This cat, however, is a big ‘un for her kin. Like a mastiff, or a Great Dane, she’s ripe for the early osteoarthritis pickings. By the time she’s five she’s likely to have accumulated some clinically significant osteoarthritis.

3. Weight

Different than size (since size isn’t always a predictor of arthritis, as I noted above), weight is nonetheless a crucial issue in the development of early onset osteoarthritis. Dogs and cats that carry excess poundage, even during the years before they develop clinically significant osteoarthritis, are contributing mightily to the amount of wear and tear their joints receive.

Think of it this way: Just as greater than average size (for the species) means more joint damage and more eventual arthritis, a greater than average amount of weight to carry (for the frame) means more joint damage and more eventual arthritis.

4. Joint conformation

This is a huge issue for the development of arthritis, early-onset or otherwise. How well-made the joints are (for lack of a more succinct description), determines much in the development of osteoarthritis. When joints aren’t well formed, as when dog breeds are dwarfed, or abnormal hip conformation is inherited, the unhappy angles at which the bones converge mean extra rubbing in all kinds of abnormal ways. This problem serves to magnify the twin issues of size and weight described above.

5. Muscle mass

Consider this: If your pets lie around a lot when they could be exercising, what do you suppose will happen to the amount of muscle they’ll have on hand to work their bones with? It’ll diminish, right? When pets have pain or stiffness, they move around less … much less. This, too, means less muscle mass. Inevitably, less muscle mass leads to weakness … and less movement. This downward "death spiral" (as I call it) is typical of osteoarthritis. But it doesn’t have to be (not if we work hard at outsmarting the adversary).

OK, so now that we better understand the enemy, next up is the meat of the issue: An examination of what YOU can do to ensure your pet isn’t one of those pets we chronically under-treat.


Dr. Patty Khuly

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