Cedars-Sinai Blog
Ask a Doc: Is Knuckle Cracking Bad?
Have you ever heard the myth that cracking your knuckles breaks the bones of your deceased loved ones? Or were you told 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 from irritated parents or teachers when you were a kid is that knuckle cracking leads to arthritis.
What’s Cracking?
We asked Robert Klapper, MD, an orthopedic surgeon and co-director of the Joint Replacement Program at Cedars-Sinai, 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,” said Klapper.
According to 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 reform 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 reforming 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,” said Klapper.
Does Cracking Your Knuckles Cause 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 lead to arthritis like the superstition says?
“Cracking your knuckles does not lead to arthritis,” said Klapper. “It does no harm at all to our joints.”
According to Klapper, repetitive cracking does not harm your joints, including the fingers, neck and ankles. That’s true whether the cracking is 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 preexisting 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."
You may wish to speak with a doctor who specializes in joint health if you experience any of the following:
- Pain when moving the joint
- Swelling around the joint
- Limited range of motion in the joint, including stiffness
- Persistent discomfort, even when not cracking the joint
“These are signs that the joint has damage—possibly from arthritis, trauma or gout,” said Klapper.
If you don’t experience pain while cracking your knuckles or other joints, 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,” said Klapper. “It’s all good.”
Frequently Asked Questions
Does knuckle cracking cause arthritis?
No, knuckle cracking does not cause arthritis or joint disorders, according to experts.
What causes the cracking sound in knuckles?
The sound occurs when nitrogen bubbles in synovial fluid burst during joint movement.
Is knuckle cracking harmful to joints?
It is generally safe if no pain or discomfort is experienced during cracking.
What are the signs of preexisting joint problems that could be aggravated by cracking?
Signs include pain during movement, swelling, limited range of motion and persistent discomfort in the joint.
