StemCell Therapy

The methodology of the study was fascinating. One of the researchers traveled around the country to examine collections of old and new skeletons, looking for signs of eburnation, which is a polished surface on the bones of the knee joint that occurs when the bones rub against each other because of the loss of cartilage associated with osteoarthritis.

RELATED: Marathon Training Doesnt Harm Knees, Even in Beginners

In total, he examined almost 2,500 skeletons from three distinct time periods:

The results showed that knee osteoarthritis occurred with roughly similar frequency in the prehistoric and early industrial skeletons, but was much more common in the postindustrial skeletons.

Of course, thats exactly what youd expect if you subscribe to the old-age-and-obesity theory. Fortunately, in many of the early industrial and postindustrial skeletons, age and body mass index (BMI) at death were recorded, which allowed the researchers include those factors in their analysis. The surprising result: Even accounting for age and BMI, knee osteoarthritis was still roughly twice as common for people born after World War II than it was for people born before it.

RW IN YOUR INBOX: Have the latest news, advice, and inspiration sent to you every day with our Runners World Newsletters.

So if its not obesity or age, what explains the apparent rise in osteoarthritis rates? This study cant answer that, but the researchers do float a few hypotheses in their discussion.

One possibility is that walking around on hard, paved surfaces all the time isnt good for our knees. In support of that possibility, they cite a 1982 paper in which sheep spent 2.5 years living either on concrete and tarmac or on wood chips and pastures. The sheep in the concrete jungle had noticeable changes in the cartilage and bone of their knee joints, and maybe we do too.

Another possibility is shoesand theyre not talking about trainers. They cite a 1998 study showing that high-heeled shoes generate abnormally high forces on the knee joint, and note that, in their analysis, women were about 50 percent more likely to have knee osteoarthritis than men.

But the biggest factor, they suspect, may be physical inactivity. Joints, like muscles, have a use-it-or-lose-it aspect. If you sit at a desk all day, you end up with thinner, lower-quality cartilage in your joints, and weakness in the muscles that would otherwise take some of the load off your joints. The problem, in other words, isnt too much running; its not enough running.

In real life, of course, things are never that neat and tidy. As the authors are careful to point out, theres lots of work remaining to explore some of these hypotheses. And even if the theories are confirmed, the fact remains that some runners, despite doing everything right, will still get osteoarthritis.

Still, the results are significant because they join a growing body of evidence that argues against osteoarthritis as a wear-and-tear disease, in which your knee are delicate instruments that will wear out if you use them too much. Your knees were made to be used, and are healthiest when used regularly. So use them!

***

Discuss this post on the Sweat Science Facebook page or on Twitter, get the latest posts via email digest, and check out the Sweat Science book!

Read more:
Knee Arthritis Has Doubled... And It's Not Because of Running - Runner's World

This entry was posted on August 19, 2017 at 7:43 am and is filed under Arthritis. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |