What Causes Joints to Pop and Crack? Should You Worry?

Written by the Nuvirox Research Team

Short answer: it depends which kind of crack you mean. The pop you get from deliberately cracking your knuckles is a different physiological event than the grinding or clicking your knees make when you stand up from a chair, and the research on each tells a different story. One is essentially harmless. The other is worth paying attention to — not because it's dangerous by itself, but because it can be an early signal.

What actually makes a joint "pop"?

When you deliberately crack a knuckle, you're stretching the joint capsule beyond its resting range. That drop in pressure pulls dissolved gas — mostly nitrogen — out of the synovial fluid, and the gas rapidly forms a cavity. Real-time MRI work has shown the sound corresponds to that cavity forming, not (as long assumed) to a bubble collapsing. Either way, it takes roughly 20 minutes for enough gas to redissolve before you can crack the same knuckle again, which is why compulsive cracking has a natural rhythm to it.

Does cracking your knuckles cause arthritis?

No credible study has found that it does. This is one of the more thoroughly debunked pieces of joint folklore. Investigations comparing habitual knuckle-crackers to non-crackers — including one widely cited study following participants for decades — found no difference in the rate of hand osteoarthritis between the two groups. The mechanism doesn't line up with cartilage damage either: cavitation happens in fluid, not on the cartilage surface itself.

So why does "crepitus" get mentioned alongside arthritis at all?

Because there's a second, unrelated kind of joint noise researchers call subjective crepitus: the grating, clicking, or crunching sound and sensation that shows up on its own, without you doing anything to trigger it — most commonly in the knees when standing, squatting, or climbing stairs. This is thought to come from a rougher, less lubricated joint surface producing friction as the bones move, rather than a gas bubble.

What Human Studies Actually Show

The Osteoarthritis Initiative found a dose-response relationship. A 2018 analysis published in Arthritis Care & Research followed knees that had no symptomatic osteoarthritis at baseline, tracking self-reported crepitus alongside knee pain and X-rays over several years. Knees with frequent crepitus at baseline were more likely to go on to develop symptomatic knee osteoarthritis than knees with no crepitus, even after adjusting for other risk factors (PMID 28470832).

A separate long-term cohort of roughly 3,500 adults ages 50–70, reported in Arthritis Care and Research, found that the odds of developing symptomatic knee arthritis rose with how often crepitus was reported — rare crepitus carried moderately elevated risk, and frequent crepitus roughly doubled the odds compared with no crepitus at all.

Honest counterweight: these are association studies, not proof that crepitus causes anything. The exact mechanism connecting joint noise to future arthritis is still unclear, and plenty of people have noisy, painless knees for years without ever developing symptomatic disease. Researchers involved in this work have also noted there's currently no established treatment or intervention specifically for painless crepitus — it's a signal worth knowing about, not a diagnosis to act on unilaterally.

When is joint noise nothing to worry about?

Occasional, painless popping or clicking in any joint — knees, knuckles, ankles, neck — is extremely common and, on its own, not a reason for concern at any age. Joint hypermobility, which affects a meaningful share of the population, makes clicking more frequent simply because there's more room for gas cavities to form. This is a separate question from why joints get stiffer with age, which has more to do with cartilage and connective tissue changes over decades than with any single noise a joint makes.

What Warrants a Closer Look

The combination that matters is noise plus something else: pain, swelling, warmth, a joint that catches or locks, or noise that started suddenly after an injury. Bone-on-bone grating after trauma, or crackling under the skin around the neck or chest, are different situations entirely and warrant prompt evaluation. See a doctor if joint noise is new, painful, or paired with visible swelling — a standard X-ray is typically the first step, since it can reveal joint space narrowing or bone spurs that a clinician can act on.

Figure: two distinct mechanisms behind joint sounds — illustrative, not to scale.

Does Anything Help Reduce Joint Noise?

There's no proven way to eliminate normal cracking, and there's no medical reason you need to. For crepitus tied to early cartilage wear, the same strategies that support joint health generally — maintaining muscle strength around the joint, staying at a comfortable body weight, and staying active rather than avoiding movement — have the best evidence behind them, though none of these are marketed as a "cure" for noise itself. It's also worth knowing that some joints are simply more prone to this kind of wear than others; we cover why knees and hips wear out before other joints in a separate article. Weather is another common trigger people ask about — see why joints hurt more when it rains for what the research actually shows there.

FAQ

Frequently Asked Questions

Is it bad to crack my knuckles every day?
No study has linked habitual voluntary knuckle cracking to arthritis or joint damage. It may occasionally cause temporary reduced grip strength or minor swelling if done forcefully, but there's no evidence of long-term harm.

Why do my knees crack every time I stand up?
This is usually painless spontaneous crepitus from air in the joint or normal cartilage surface friction, and it's extremely common. It's worth mentioning to a doctor if it's new, painful, or accompanied by swelling.

Can supplements or exercise stop joints from cracking?
There's no clinical evidence that any supplement eliminates joint noise. Strengthening the muscles around a joint can improve stability and comfort, which some people notice reduces symptomatic clicking, but painless noise itself isn't something research shows can be reliably stopped.

Is knee crepitus the same as arthritis?
No. Crepitus is a symptom, not a diagnosis. Cohort data shows frequent crepitus is associated with higher odds of later developing symptomatic knee osteoarthritis, but many people with noisy knees never develop it, and a formal OA diagnosis requires clinical and often imaging evaluation.

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The bottom line: the crack from deliberately popping your knuckles and the grinding your knee makes standing up are different phenomena with different research behind them. The first has a long track record of being harmless. The second — frequent, spontaneous joint crepitus — is a modest but real signal worth mentioning to a doctor, especially if it's new or accompanied by pain, even though it's not proof of arthritis on its own.

References

1. Kalunian KC, et al. Subjective Crepitus as a Risk Factor for Incident Symptomatic Knee Osteoarthritis: Data From the Osteoarthritis Initiative. Arthritis Care Res. 2018;70(1):53-60. PMID: 28470832.
2. Lo GH, et al. Association Between Crepitus and Development of Symptomatic Knee Osteoarthritis. Arthritis Care Res. 2018. Baylor College of Medicine cohort analysis, n=3,495.
3. Deweber K, et al. Knuckle cracking and hand osteoarthritis. J Am Board Fam Med. 2011. No association found between habitual knuckle cracking and hand OA.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.