Is Cracking Your Knuckles Bad For You? Here's What Science Says

Cracking your knuckles is a habit many people find oddly satisfying — but is it harmful? This long-standing debate has sparked concern, warnings, and even myths. Let’s look at what the science says.

What’s behind the pop?

The cracking sound doesn’t come from bone rubbing or joint damage. It’s caused by gas bubbles rapidly collapsing in the synovial fluid — the lubricant within your joints. This phenomenon is known as cavitation. 

Why do people crack their knuckles?

The habit can stem from:

• Stress relief

• Tension release

• A self-soothing ritual

• Simply a habitual behaviour

Cracking your knuckles does not cause arthritis and is generally harmless if done in moderation.

The Potential Risks

While cracking your knuckles isn’t harmful in itself, frequent or forceful cracking may sometimes lead to:

• Joint instability and swelling

• Soft tissue irritation, if done excessively or with abnormal joint mechanics
  

Some experts warn of possible soft tissue irritation or joint laxity, but no strong evidence links it directly to osteoarthritis.

The Arthritis Question: Myth or Reality

For generations, parents and grandparents have cautioned against this habit, fearing it would lead to a lifetime of stiff and painful joints.
The most cited experiment is by Dr. Donald Unger, who cracked the knuckles of one hand for over 60 years and left the other untouched. He found no difference in arthritis development between the two hands.
Multiple studies since then — including one published in The Journal of the American Board of Family Medicine in 2011 by Castellanos and Axelrod — have supported this conclusion: knuckle cracking does not increase your risk of arthritis.

Did you know?

Once a joint is cracked, it typically takes 15–30 minutes before it can be cracked again. That’s the time needed for the gases in the synovial fluid to re-dissolve and reset the joint for another cavitation. 

When to see a doctor?

If you experience pain, swelling, joint issues, or ligament injury while doing it, consult a healthcare provider to rule out other conditions.

What if you want to stop?

If you’re trying to break the habit:

• Engage in exercises that strengthen your hand muscles.

• Try stretching your hands and fingers to release tension.
  

• Keep your hands busy with a stress ball or fidget toy.
  

• Identify triggers (e.g., stress or boredom).
  

• Practice mindfulness techniques to reduce the urge.
  

In short, cracking your knuckles might annoy others, but it likely won’t harm you — unless it starts to hurt. Know your body, and pop wisely. 

Reference: 

1. Deweber, K., Olszewski, M., & Ortolano, R. (2011). Knuckle cracking and hand osteoarthritis. The Journal of the American Board of Family Medicine, 24(2), 169–174. https://doi.org/10.3122/jabfm.2011.02.100156

By Dr. Shreya Vohra, MBBS

_MSM/DP