Osteoarthritis, and a Post-Industrial Era Mystery

The latest issue of Harvard Magazine looks at a curious mystery.

Two biology researchers from Harvard University discovered the mystery after visiting medical institutes across the country and examining skeletons over the centuries.

They were searching for evidence of knee osteoarthritis (bone-on-bone rubbing in places where the cartilage has completely eroded, which leads to polished bone surfaces that are a telltale sign of the disease).

When they compared the skeletons from the prehistoric and industrial eras to those from the postindustrial, they found that the prevalence of knee OA has more than doubled since World War II.

You might think: Sure, of course it’s higher. People live longer. More people today are obese.

But controlling for age and body mass index didn’t make the difference go away. To be sure, obesity contributes hugely to knee OA. But it wasn’t causing the spike in cases.

The researchers still aren’t sure what’s going on, but they’re testing a hypothesis that I think will yield their answer.

Physical inactivity, they speculate, may be what’s to blame. The mid-twentieth-century shift to service-sector jobs put more people in workplaces where they got less movement. The modern desk rat was born.

We sit, and sit, and sit, and sit, and then wonder one day why our knees hurt.

Because our knees weren’t designed to do nothing at all for long stretches?

Or, as the article says, in more prolix language: there’s a “suspicion that OA is a case of human physiology being partly maladaptive to modern environments.”

Healthy, joint-nourishing motion IS important.

This, I believe, is the key to preventing knee pain, or once you have it, recovering your pain-free knees once again.

The Difficulty of Taking a Step Backwards to Move Forward

With New Year’s resolutions thick in the air, I thought this might be a good time to talk about what might be the hardest thing to do when trying to heal aching knees.

A lot of people, especially fit people, quickly take to heart my message of “motion” when it comes to healing. After all, living things that stay at rest gradually become weak and begin to fall apart.

So athletic people immediately want to go outside and start walking 5,000 steps a day to recover their knee health.

But the motion imperative can be very dangerous, as too much motion just leads to more knee pain. The key, I strongly believe, lies in figuring out the “proper amount” of appropriate motion. And, as I've said many times before, determining the “proper amount” can be very, very hard, especially initially.

What’s sometimes needed is a willingness to go backwards to go forward.

For me, that involved scaling my program way, way back. I went from walking thousands of steps a day to simply walking once around a pool and resting for ten minutes, then repeating the sequence. Talk about boring! This also represented a kind of “rock bottom” moment for me – if that’s all the movement my knees could tolerate, they must be much weaker than I imagined.

As it turned out, hitting rock bottom was one of the best things that happened to me. I needed to accept where I was – where I really was, and not where I thought I was – to start improving. Those simple pool walkarounds made my knees feel consistently good, and I needed that. I needed to escape the frustrating swings of emotion, where my knees felt good for a few days, then bad for a few, and my progress seemed to stall.

Going too fast, too aggressively, can leave you baffled and frustrated. Sometimes it pays off to go backwards – figure out the least strain you can put on your joints, while having them consistently feel better.

Once you establish that baseline, then you can start to move forward.