Cracking knuckles causes arthritis
Multiple studies, including a widely cited self-experiment conducted over decades, have found no link between habitual knuckle cracking and osteoarthritis or joint damage. The sound is produced by gas bubble formation or collapse in the synovial fluid.
What we know
Knuckle cracking is a common habit that has long been associated in popular belief with arthritis. The sound is caused by the rapid formation or collapse of gas bubbles (primarily nitrogen and carbon dioxide) within the synovial fluid of the joint, not by bone-on-bone contact or damage.
A study published in the Annals of the Rheumatic Diseases and data from the Johns Hopkins Arthritis Center found no association between habitual knuckle cracking and the development of hand osteoarthritis. One frequently referenced study involved a physician who cracked the knuckles of one hand for over 60 years while leaving the other as a control, and found no difference in arthritis development.
A 2011 study in the Journal of the American Board of Family Medicine also found no significant association between knuckle cracking and hand osteoarthritis across a sample of 215 subjects. Harvard Health has noted that while some studies found a possible association between cracking and hand swelling or reduced grip strength over long periods, the overall evidence against an arthritis link is strong.
While habitual knuckle cracking is not known to cause arthritis, it can occasionally cause minor soft-tissue irritation if done forcefully or very frequently. The consensus among rheumatologists is that the arthritis claim is not supported by evidence.
Common claims
- Cracking knuckles leads to arthritis over timeNo evidence found
- The cracking sound means bones are grinding togetherFalse - it is gas bubbles
- Habitual crackers have weaker grip strengthInconclusive, limited evidence
- Doctors advise against knuckle cracking for joint healthNot supported by guidelines