Does cracking your knuckles really cause arthritis?
I've been cracking my knuckles for 20 years and my mom keeps telling me I'm going to get arthritis. Is there any scientific evidence for this? My hands feel fine but I'm in my 40s now.
Expert Answer
Dr. Karen Wright, DPT — Physical Therapy & Rehabilitation
Good news — this is one of the most persistent health myths, and the science is firmly on your side. Cracking your knuckles does not cause arthritis.
What the Research Says
- The famous self-experiment: Dr. Donald Unger cracked the knuckles on his left hand every day for 60 years while leaving his right hand alone. After six decades, neither hand showed arthritis. He published his findings and won an Ig Nobel Prize for it.
- Larger studies confirm it: A 2011 study in the Journal of the American Board of Family Medicine examined 215 people aged 50–89 and found no difference in arthritis rates between habitual knuckle crackers and non-crackers.
- Multiple reviews: No published study has ever found a link between knuckle cracking and osteoarthritis.
What's Actually Happening When You Crack
The popping sound comes from gas bubbles (mostly carbon dioxide) rapidly forming or collapsing in the synovial fluid that lubricates your joints. It's called cavitation. A 2015 MRI study in PLOS ONE confirmed this mechanism in real-time. It's a normal physical phenomenon, not joint damage.
Any Risks at All?
While arthritis isn't a concern, some studies suggest that very frequent, forceful cracking over decades may be associated with slightly reduced grip strength or mild hand swelling — but even this evidence is weak and inconsistent.
Bottom line: Tell your mom the science says she can relax. Crack away — your knuckles are fine.
This is general health information. Consult your physician if you experience joint pain or swelling.