As a lifelong knuckle cracker, I've heard the spiel dozens of times-you know, keep popping and you'll end up with arthritis. Because of this, I've always kept an eye out for any proof that'll prove my naggers wrong. Unfortunately, all I've figured out over the years is that there's a lot of conflicting information out there when it comes to the harm that popping our joints causes.
More than a few times, annoyed parents and teachers have told me I'll end up with old, arthritic hands if I continue cracking my knuckles-but so far, my fingers look no worse for the wear. Is it really a bad choice for our joint health? Does it actually (crossing my crackable fingers) help us? Is repetitive cracking risky? In an attempt to get to the bottom of the situation, I consulted medical authorities for their take on cracking.
"The jury is still out on whether cracking joints is a harmful or benign process," says Lindsay Segal, a graduate practitioner in Samuel Merritt University's physician assistant program. But as it turns out, studies have shown a few reliable connections between knuckle cracking and some particular joint-related problems.
What's in a Pop?
First, I figured I should find out a little more about my knuckles. Like all joints, they're the place where two bones come together to allow movement-we have them in our wrists, knees, and everywhere else we can bend. Tough, flexible tissues called ligaments hold them together. Joints are covered with a capsule filled with a special kind of liquid, called synovial fluid, that acts as a lubricant as we move around; they also contain small amounts of dissolved gas, which is what causes that pop when we crack them.
"The noise you hear with the cracking of a joint is due to a sudden release in joint pressure," says Segal. "This releases the dissolved gases in the joint fluid." This explains why we can't pop and pop and pop-the gas has to build up again before it can be released, which takes about twenty minutes.
So why, then, can some of us crack more than others?
"It's speculated that the laxity, or looseness, of the joint itself increases the more you crack it," says Segal. It makes sense, therefore, that it's very easy for me to crack my knuckles every twenty minutes, while some of my friends are unable to get even one pop out of theirs.
Joints might also make cracking sounds when our smooth cartilage breaks down, creating a rough joint surface (this is typical in arthritic joints). Another cause for cracking is when a tendon moves slightly out of place and then snaps back-this occurrence is common in knees and shoulders. Knees and ankles can also make cracking sounds when the ligaments tighten as we move our joints.
Back to the whole reason I care about all this in the first place: are all those cautionary remarks actually based on facts, or are the people who make them just annoyed by my constant cracking? Is this release of built-up gas harmless? There are two arguments against cracking that I always hear: one, my knuckles are going to get bigger if I keep cracking, and two, I'm going to end up with arthritis. Well, neither of these scenarios is actually likely (take that, naysayers!), but there is some truth to the idea that joint cracking can cause some harm.
As for the knuckles and arthritis? "Studies have concluded that cracking a joint doesn't lead to arthritic changes," says Segal. "But it is associated with joint swelling and decreased joint strength." A Vanderbilt University write-up on the topic agrees, stating that there isn't any direct scientific evidence to support this rumor. Studies show no change in the likelihood of getting arthritis between people who habitually crack and people who don't. They have, however, found that people who already have arthritis or weakened joints could make their condition worse by cracking their knuckles.
Another study, this one by Snajiv Naidu, a Penn State professor of orthopedics, agrees, stating that cracking doesn't strain or overextend ligaments and tissues to a point that would cause arthritis. Naidu asserts that we'd have to literally disrupt our joints with injury-causing excessive force to cause any chronic or long-term harm.
The Real Risks
In another study, published in the Annals of Rheumatic Diseases, researchers looked a little deeper to figure out just what kind of harm, if not arthritis, we're actually looking at. Unfortunately (for us poppers, at least), they found that 84 percent of long-term knuckle crackers experienced hand swelling later in life, while only 6 percent of noncrackers did. Another interesting finding: habitual crackers are more likely to be manual laborers and frequently drink, smoke, and bite their nails. Gateway habit? Or does manual labor just compound stress on hands, making people more likely to have issues? This topic is clearly still open for debate, but this study's finding about impaired hand function later in life is strong-so maybe cracking our bones is something we should try to limit after all.
The good news: there isn't any scientific evidence that suggests knuckle cracking is harmful (or beneficial) to our joints and overall health. The not-so-great news, of course, is that it has been linked pretty clearly to swelling and decreased hand strength later in life.
Old or young, swelling or no swelling, habitual cracker or not, if you're feeling pain when any of your joints pop, you should definitely consult a doctor to rule out any underlying abnormalities, says Segal.
The next time I get that urge (twenty minutes from now), I'll at least think twice about it. Although cracking doesn't bother me now-and won't give me arthritis-in thirty or forty years, I'd like to be able to uncork my own wine bottle, thank you very much.