Cracking Your Knuckles: Myths and Facts

Fact: There is no strong scientific evidence to suggest that people who crack their knuckles regularly are more likely to develop arthritis than those who don’t.

“The idea that cracking your knuckles leads to arthritis is one of the most common misconceptions we hear,” says Kalpit Shah, MD, a hand and upper extremity orthopedic surgeon at Scripps Clinic Jefferson in Oceanside. “Multiple long-term studies have found no clear link between habitual knuckle cracking and the development of osteoarthritis in the hands or fingers.”

While it may sound like the joints are being damaged, arthritis is caused by other factors such as age, genetics, wear and tear, previous injuries and inflammation.

Fact: The sound of knuckles cracking can be alarming, but it isn’t caused by bones rubbing against each other. Instead, it’s likely coming from bubbles in your joint fluid.

When you crack your knuckles, you pull the surfaces of your joints apart slightly. Each joint is lubricated with synovial fluid, which contains dissolved gases like nitrogen and carbon dioxide. As the joint stretches, pressure inside of it drops, allowing gas to quickly form a bubble. When that bubble breaks, it creates a popping sound.

“Healthy joints are designed to move and shift slightly,” says Dr. Shah. “The pop is part of normal function inside a fluid-filled space.”

Moreover, once a joint has cracked, it takes about 15 to 30 minutes for the gas to dissolve into the fluid and create more bubbles. This is why you cannot crack the same knuckle multiple times in a row. 

Another source of noise around a joint may be from the tendons that connect muscles to the bones. Some people may have bones that protrude more than others. When the tendons move over the bony protrusions, they can create a snapping sound.

Fact: For most people, simply cracking their knuckles does not significantly affect their hand strength. However, forceful manipulation of the hands or fingers, especially repeated twisting beyond a joint’s normal range, could potentially irritate soft tissues over time.

Gentle joint popping is one thing; vigorous or aggressive wrenching is a different story and should be avoided.

Fact: Habitual cracking does not cause knuckle enlargement.

While forceful twisting may cause swelling around the knuckle that causes it to appear larger, typical non-aggressive knuckle cracking should not lead to swelling. 

For most people, knuckle cracking is generally harmless, as long as you don’t experience pain, swelling or instability in your fingers or hands.

“If you feel pain, swelling, stiffness or warmth in the joint when you crack your knuckles, or you notice a decreased range of motion, it may be a symptom of an underlying problem,” says Dr. Shah. “It could indicate ligament strain or joint inflammation, and you should have it checked out by your doctor.”