“Cracking joints” and “popping knuckles” are an interesting and poorly understood phenomenon. There are many theories as to why joints crack or pop, but the exact cause is unknown. Painless cracking of joints is – as a rule – not harmful, however common sense generally would suggest that the intentional and repetitive cracking of joints is not recommended.
Between 25 and 54 percent of all people crack their knuckles multiple times a day. This may indeed aggravate the people around you, but what evidence is there that it causes harm, and in particular arthritis?
There are a couple of studies looking into this. In 2011 a study of over 200 people found that 20% of the participants regularly cracked their knuckles. 18.1% of those who cracked their knuckles had hand osteoarthritis, and 21.5% of those who did not had hand osteoarthritis. This means that there is no statistical evidence to show that those who cracked their knuckles were more likely to develop arthritis.
In another study 300 patients were assessed. Here 25% of the participants regularly cracked their knuckles, and again there was no evidence of osteoarthritis. There was evidence of hand swelling and lower grip strength. They also found that knuckle cracking was associated with manual labour, nail biting, smoking and drinking alcohol and they concluded that habitual knuckle cracking results in functional hand impairment. The damage was likely the result of the repeated stretching and loosening of the ligaments during the activity.
So whilst the research shows you are unlikely to get arthritis from cracking your knuckles, you are damaging your hands so this is a habit that is well worth breaking.
You can find more information on these web pages (each will open in a new window)
Knuckle Cracking and Hand Osteoarthritis
Effect of habitual knuckle cracking on hand function