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A myth. One doctor cracked one hand for 60 years. No arthritis in either.
Where it came from
The sound is alarming, and generations of grandparents have warned that it will ruin your joints.
What’s actually true
The crack is a bubble forming in the fluid that lubricates the joint as its surfaces are pulled apart; MRI films have caught the cavity appearing. Studies comparing habitual crackers with non-crackers find no difference in rates of arthritis.
The physician Donald Unger cracked the knuckles of his left hand, and only his left, at least twice a day for some sixty years, keeping the right as a control. Neither hand developed arthritis, and his one-man experiment won an Ig Nobel Prize in 2009.
Further reading
- Unger, “Does knuckle cracking lead to arthritis of the fingers?”, Arthritis & Rheumatism (1998)
- Kawchuk et al., PLOS ONE (2015)