Can You Wear Out Your Joints?

There's a joke I heard when I first started studying arthritis: A 90 year-old man sees his doctor complaining of pain in his knee. His doctor asks him, "What do you expect? You're 90 years-old." The old man replies, "Yes, but my other knee is also 90 and it feels fine."

That pretty much sums up why "wear and tear" arthritis is not an accurate description of osteoarthritis (OA), or degenerative joint disease. Just because you live a long time, doesn't mean you'll inevitably wear out your joints.

Why Your Joints Aren't Like Tires

Degenerative joint disease is more common with aging, so it may seem logical to assume osteoarthritis is due to "wear and tear." It's also true that extreme or unusual stress on joints can cause damage that leads to osteoarthritis. But for most people, arthritis due to normal wear and tear is a myth. Your joints aren't like a car's tires or a light bulb that inevitably wears out over time with enough use.

Osteoarthritis occurs when the smooth, shiny cartilage that lines the joint deteriorates. In some cases, this can happen after an injury but for most people it's a result of aging and genetics. The most common locations for osteoarthritis are the:

• Knees

• Hips

• Finger and toe joints

• Upper and lower spine.

One thing we know for sure about osteoarthritis — it's very common. An estimated 21 million people in the United States alone have OA. If you're fortunate enough to live to age 75 or older, chances are perhaps as high as 70% to 90% that you'll have OA in at least some joints. With these numbers staring at you, it's reasonable to wonder if there's something you can do to prevent it. Specifically, should you limit your activities so you don't "wear out" your joints?