Cracking Knuckles May Cause Damage, but Not Arthritis
A review of studies on knuckle cracking has found that there isn't enough evidence that the habit causes arthritis, but it may damage the joints in other ways.
The 2018 review, which was published in Clinical Anatomy, looked at 26 studies on knuckle cracking — the habit where people pull or move the joints in their fingers to make a cracking sound.
When knuckles are cracked, it isn't the bones that make the sound, but instead bubbles of gas in the fluid around the joints. However, experts disagree on whether it's the creation of the bubbles or the popping of the bubbles that makes the cracking noise.
The review looked at several studies that had found that knuckle cracking wasn't associated with osteoarthritis, a type of arthritis that affects cartilage. However, some studies showed it may cause other damage.
A 2017 study looked at 35 people who cracked their knuckles and 35 people who didn't. It found that those who cracked their knuckles had increased thickness in their cartilage, which may be an early sign of osteoarthritis. However, as the study was on young people with an average age of about 24, researchers couldn't be sure.
Another study from 1990 on 300 people found that people who cracked their knuckles had more hand swelling and less grip strength than those who didn't.
The review authors said that the energy released by bubble pops may damage the joint, and the force someone uses to crack their knuckles may also damage their ligaments and soft tissue over time.
"Knuckle cracking over the years will cause repetitive trauma to the joints and cartilage," co-author Rod Oskouian, from the Swedish Medical Center in Seattle, told The Washington Post. However, he also said that the habit is probably harmless for most people.
It's thought that 25% to 54% of people crack their knuckles, however, not all experts agree that it's harmless. Some say there are good reasons to not crack your knuckles at all, while others say it's okay, as long as there's no pain.
