Ask a Doc: Is Knuckle Cracking Bad?

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Have you ever heard the myth that cracking your knuckles breaks the bones of your deceased loved ones? Or that the number of noises you hear when you twist, pull, and bend your fingers reveals how many people are in love with you?

“The noise of cracking or popping in our joints is actually nitrogen bubbles bursting in our synovial fluid.”

There’s a long list of myths and superstitions about knuckle cracking, but the one you probably heard most often was delivered by irritated parents or teachers when you were a kid: Cracking your knuckles will give you arthritis.

What’s cracking

We asked Dr. Robert Klapper, orthopaedic surgeon and co-director of the Joint Replacement Program, to explain what actually happens when you hear your joints snap, crack, and pop.

“The noise of cracking or popping in our joints is actually nitrogen bubbles bursting in our synovial fluid,” says Dr. Klapper.

According to Dr. Klapper, synovial fluid lubricates your joints like motor oil in a car’s engine, reducing friction and preserving our cartilage. The nitrogen bubbles within the synovial fluid usually take 20 minutes to re-form in your joints before they can crack again.

Part of the appeal of knuckle cracking could be that 20-minute lull, when gas bubbles are re-forming in the synovial fluid. You might feel looser during that period, as if you’ve relieved pressure from your joints.

But the satisfaction is mostly in your head.

“Feeling good after cracking your knuckles is a psychological experience,” says Dr. Klapper.

Were your parents right about arthritis?

Maybe it’s the fun sound of cracking joints, or maybe it’s the perceived sense of relief: For some people, knuckle cracking becomes a daily habit. Does repeated knuckle cracking then lead to arthritis like the superstition says?

“Cracking your knuckles does no harm at all to our joints,” says Dr. Klapper. “It does not lead to arthritis.”

'Cracking your knuckles does no harm at all to our joints. It does not lead to arthritis,' says Dr. Klapper. Click To Tweet

According to Dr. Klapper, knuckle cracking itself does no harm to your fingers, neck, ankles, or other joints that pop and crack throughout the day—whether from normal day-to-day motions or compulsive habits like pressing our knuckles or twisting your neck until you hear that familiar crack.

However, if you experience discomfort while cracking, then there could be a pre-existing condition that is aggravated by twisting and pressing the joint.

If you don’t experience pain while knuckle cracking, then you’re free to indulge yourself.

“Pain, swelling, or limited motion are signs that the joint has damage—possibly from arthritis, trauma, or gout,” says Dr. Klapper.

If you don’t experience pain while knuckle cracking, then you’re free to indulge yourself, even if your occasional snapping, cracking, and popping sometimes startles those around you.

“Some of us are just noisier than others when our joints crack,” says Dr. Klapper. “It’s all good.”

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