With varying frequency it appears that up to 54% of people crack their knuckles, with men being more likely to have this bad habit than women.
As Physiotherapists, we have all at some point been asked, “Does cracking knuckles really cause arthritis in the hands?”
Here is the evidence-based answer. From a 2011 study (reference 1), they analyzed individual’s knuckle cracking habits (frequency and duration) and their hand radiographs.
20% of subjects admitted to quite frequently cracking their knuckles. The prevalence of hand osteoarthritis among those who cracked their knuckles was 18%, but for those who didn’t crack their knuckles, it was actually higher at 21%.
Basically, it appears that a history of habitual knuckle cracking may not be a risk factor for developing hand osteoarthritis. So it is clearly an old wives’ tale.
However, the established risk factors for developing hand osteoarthritis are:
• age
• a family history of hand osteoarthritis
• previous hand injury (e.g. fracture)
• a lifetime of heavy labour with the hands
Is Knuckle Cracking then “Bad”?
Even though it doesn’t cause osteoarthritis, habitual knuckle cracking may still be harmful. Another study (reference 2) looked at 300 adults and of them, 25% were habitual knuckle crackers.
The habitual knuckle crackers were more likely to:
• have swelling of the hands
• have lower grip strength
• smoke, drink alcohol and have a nail biting habit
What does all this mean? Since there was no direct association, we cannot scientifically say that habitual knuckle cracking necessarily causes nail biting, smoking and alcoholism.
Studies show that habitual knuckle cracking may not cause arthritis, but it may weaken grip strength. We hope this motivates others to stop or at least reduce their annoying bad habit.
The truth is that cracking joints can be very addictive. That’s why it’s so difficult for some to simply stop the habit. The same way it’s difficult for some to stop going for regular spinal manipulations. We have patients who admit to “needing” their neck or back “cracked” regularly even though the relief is at best temporary.
References
1. Deweber K, et al. “Knuckle Cracking and Hand Osteoarthritis.” J Am Board Fam Med. 2011 Mar-Apr; 24(2):169-74.
2. Castellanos J, Axelrod D. “Effect of Habitual Knuckle Cracking on Hand Function.” Ann Rheum Dis. 1990 May; 49(5):308-9.
