Knuckle-cracking’s effects: The Jury’s out

Odds are, you’ve heard a wives’ tale or two. Some wives’ tales are quickly dismissed (if you swallow a watermelon seed, a watermelon will grow in your stomach). Some are just confusing (Feed a cold, starve a fever — or is it the other way around?)

But other wives’ tales are less obviously accepted or dismissed. A common belief is that cracking knuckles causes them to become enlarged and can even lead to arthritis. But is there any truth to this tale?

Though there has been conflicting research, the current accepted belief is that knuckle popping has no immediate negative effects on one’s joints, nor does it cause any long-term damage, says Carol Ryan, occupational therapist at Lawrence Orthopedic Surgery. However, no conclusive evidence proving this belief exists.

“The jury’s still out on it,” Ryan says.

Even though the link hasn’t been firmly disproven, ongoing research on the topic is slim, if any, Ryan says.

So if knuckle cracking doesn’t cause arthritis, what does?

Several different types and causes of arthritis exist. The most common form of arthritis occurs because of degenerative joint problems, or normal wear and tear, says Ryan.

Pain from arthritis can be combated with medication and/or aerobic exercise. Because knuckles cracking doesn’t cause arthritis, quitting cracking won’t make arthritis go away, either.

The noise that follows knuckle cracking is why some people believe the practice is harmful to joints.

“It just sounds like it would be a deforming kind of thing, hearing the popping or cracking,” Ryan says.

However, the popping sound doesn’t indicate damage to the joints. When people crack their knuckles, the bones in their fingers are being pulled apart. The pressure inside the joint is lowered, and a gas mixes with the fluid in the joints. This creates a gas bubble, and when the bubble bursts, it makes the popping sound, says Ryan.

Are you addicted to popping?

A common reason for cracking knuckles is to decrease pressure in one’s joints. Though it might feel good, it is unusual for a person to become addicted to knuckle cracking. Instead, it becomes more of a habit or mindless activity. Ryan compares the practice to fingernail chewing.

And despite the common belief linking cracking knuckles to arthritis, Ryan says she’s never encountered any patients who thought their joint pains were caused by their knuckle-cracking habit.