Is Knuckle Cracking Harmful?
Habitual knuckle cracking does not cause osteoarthritis or significant joint damage, though it may be associated with minor hand swelling and reduced grip strength in some individuals.
Evidence on Osteoarthritis Risk
The most robust evidence demonstrates no causal relationship between knuckle cracking and osteoarthritis:
Multiple observational studies have failed to show an association between habitual knuckle cracking and osteoarthritis 1, 2. A comprehensive review confirms that decades of habitual knuckle cracking is not associated with clinical or radiographic evidence of osteoarthritis 2.
A prospective study of 400 metacarpophalangeal joints in 40 subjects found no differences in QuickDASH scores, joint laxity, or grip strength between habitual knuckle crackers and non-crackers 3. No swelling was observed in any subjects, even immediately after documented cracking events 3.
Potential Minor Effects
While osteoarthritis risk is not increased, some studies suggest minor associations:
One older study of 300 patients found habitual knuckle crackers were more likely to have hand swelling and lower grip strength, though no increased prevalence of hand arthritis was detected 4. This study also noted associations with manual labor, nail biting, smoking, and alcohol use, suggesting potential confounding factors 4.
Immediately after cracking, joints demonstrate small increases in range of motion (passive total ROM increased by 7.7°), which may explain why some individuals find the practice satisfying 3.
Acute Injury Risk
The primary concern is not chronic damage but acute injury:
- Forceful manipulation to achieve knuckle cracking can result in acute injuries, including ligamentous or capsular damage 5. These injuries typically respond well to conservative treatment but represent a real, if uncommon, risk 5.
Clinical Recommendation
Reassure patients that habitual knuckle cracking does not cause arthritis or long-term joint damage 1, 2. However, counsel them that: