Does Cracking Your Knuckles Cause Arthritis? What the Evidence Shows

Ranked by how widely believed each claim is, with the verdict the evidence actually supports.

The useful distinction runs through the whole page. Sound on its own carries almost no information about joint health. Sound accompanied by pain, swelling, giving way or locking carries a great deal, and the two get lumped together constantly.

This is a documentary review of the published research on joint cracking rather than an assessment of your hands. Five claims were selected on how often they come up, and the verdict on each reflects the best available study rather than consensus opinion.

The sources read were the 2011 case-control study by DeWeber and colleagues, which compared 215 people aged 50 to 89 with and without radiographic hand osteoarthritis; the 2015 PLOS ONE study using real-time cine MRI to image what happens inside a joint at the moment it cracks; the 1990 study by Castellanos and Axelrod in the Annals of the Rheumatic Diseases, which examined 300 people; and a 2017 study using physical examination and ultrasound to look for detectable changes after cracking. Evidence checked in August 2026.

The honest limit is that the evidence base here is small. This is not a question that attracts research funding, so the entire literature amounts to a handful of studies, most of them observational and one of them a single doctor experimenting on himself for six decades. The consistency of the answer across those studies is what makes it convincing, rather than the weight of any one of them.

Ask whether it hurts. This is the question that does almost all the work. Painless noise in a joint that moves and functions normally is a mechanical curiosity.

Ask whether it is new. A joint that has clicked for twenty years is telling you nothing. A joint that started clicking last month, having been quiet before, is worth a thought.

Ask whether anything else changed. Swelling, giving way, locking, or loss of range alongside the noise moves this into a different category.

Ask whether you can reproduce it deliberately. A crack you can produce on demand and then not repeat for 20 minutes is the gas cavity mechanism. A click that happens every single time you move the joint through a particular arc is a structure catching, which is a different thing.

Ignore the volume. How loud it is bears no relationship to how significant it is, and loud painless cracks worry people far more than quiet painful ones.

The claim

Habitually cracking your knuckles damages the joint surfaces and leads to osteoarthritis of the hands in later life.

What the evidence supports

It does not support this. The 2011 case-control study assessed 215 people aged 50 to 89 for radiographic hand osteoarthritis and found no association with knuckle cracking, and no relationship with how often or how long people had done it. Total lifetime cracking made no difference either.

The single-subject experiment

Dr Donald Unger cracked the knuckles of his left hand at least twice a day for more than sixty years while deliberately leaving his right hand alone, giving an estimated 36,500 cracks on one side and none on the other. X-rays of both hands showed no difference and no arthritis on the cracked side. It is a sample of one, and it is an unusually well-controlled sample of one, since the comparison hand belonged to the same person.

Why the belief persists

Hand osteoarthritis is common, knuckle cracking is common, and both become more noticeable with age. Two things increasing together is exactly the pattern that generates a false causal belief, and this one has the additional advantage of sounding like it should be true.

Limits and cautions

These studies looked at osteoarthritis specifically. They did not test every conceivable long-term effect, and absence of an association in a study of 215 people is not the same as proof of complete harmlessness.

Why it ranks first

It is the most widely believed claim about joints in general circulation, and the evidence against it is the clearest on this page.

The claim

The crack is the sound of a gas bubble in the joint fluid collapsing under pressure.

What the evidence supports

This was the accepted explanation for decades and the imaging does not support it. The 2015 PLOS ONE study filmed finger joints with cine MRI at 3.2 frames per second while traction was applied, and found that the crack coincides with a cavity forming rather than collapsing. The cavity then remained visible after the sound.

What is actually happening

The process is tribonucleation. Two surfaces held together by fluid resist separation until a critical point, then separate suddenly, and dissolved gas comes out of solution into the space that opens. The sound is the joint surfaces parting and the cavity appearing.

Why it matters

It explains the refractory period. You cannot crack the same knuckle twice in a row because the gas takes around 20 minutes to redissolve before the mechanism can repeat. It also explains why nothing is being crushed or worn, which is the part relevant to claim one.

Limits and cautions

The 2015 study imaged ten joints in a small number of participants. The finding has been influential and the sample was not large.

Why it ranks second

It is the most commonly repeated explanation, including by clinicians, and it has been superseded.

The claim

Long-term knuckle cracking produces visibly swollen knuckles and measurably weaker grip, even if it does not cause arthritis.

What the evidence supports

This is the one claim with any supportive data, and it is weak. The 1990 study of 300 people found no excess of hand arthritis among habitual crackers, and did report more hand swelling and lower grip strength in that group.

Why it probably does not mean what it appears to

The knuckle-crackers in that study were also considerably more likely to be manual labourers, to smoke and to drink alcohol. Manual work alone plausibly explains both findings, and the study could not separate the habit from the occupation. A 2017 study using blinded physical examination and ultrasound found no detectable changes attributable to cracking.

What to take from it

The finding has not been replicated in 35 years and the better-controlled follow-up did not reproduce it. Treat it as an unresolved question rather than an established harm.

Limits and cautions

Genuinely swollen knuckles are worth attention regardless of what you blame them on, because soft symmetrical swelling across the knuckles is the pattern of inflammatory arthritis.

Why it ranks third

It is the only claim with a study pointing towards harm, and the confounding is severe enough that it cannot carry much weight.

The claim

Clicking, popping and grinding in knees, shoulders, hips or the neck indicates that something inside the joint is worn or damaged.

What the evidence supports

Painless joint noise is extremely common in joints that are structurally normal. Tendons flick over bony prominences, ligaments shift position, and gas cavitation occurs in joints throughout the body. Knees in particular are noisy in healthy young adults.

Why it matters

The belief that noise means damage changes behaviour. People stop squatting because their knees click, stop reaching overhead because a shoulder pops, and lose strength and range as a result. The avoidance does far more harm than the noise it was intended to prevent.

Where noise does carry information

A single loud pop at the moment of an injury is meaningful, particularly at the knee. Noise that appeared alongside new pain or swelling is meaningful. Noise that has been there for years and does not hurt is not.

Limits and cautions

Grinding that is felt as well as heard, accompanied by pain on load, is worth assessing, and it is the pain and the load response that make it worth assessing rather than the sound.

Why it ranks fourth

It is less specific than the claims above and it causes more day-to-day harm, because it makes people avoid the exact movements their joints need.

The claim

Since joint noise is harmless, clicking that hurts can also be ignored.

What the evidence supports

This is where the reassurance stops. Everything above concerns painless noise in a joint that works normally. Noise accompanied by pain, swelling, locking, catching or giving way is a symptom, and the noise is the least important part of it.

What to look for

A knee that clicks and then locks or gives way. A shoulder that clunks and is painful overhead. A hip that clicks with groin pain on rotation. A finger that catches and has to be straightened with the other hand, which is trigger finger and is treatable. Any joint that became noisy at the same moment it became painful.

What to do about it

Have it assessed rather than self-diagnosing from the sound. The assessment is about what provokes the pain, what range is lost and how the joint behaves under load, none of which the noise tells you.

Limits and cautions

The reverse mistake also happens. People with genuinely painful, mechanically catching joints delay getting seen because they have read that joint noise is normal, which is true and does not apply to them.

Why it ranks fifth

It is the least commonly stated claim on this page and the only one where believing it can cost you something.

Four of the five claims resolve to reassurance. The fifth is the reason this page does not simply end at "it is fine", because the reassurance in the first four is routinely applied to a joint it was never about.

If you crack your knuckles habitually and they do not hurt, there is no evidence you are causing arthritis, and no reason from the research to stop.

If someone has told you it will give you arthritis, the 2011 case-control study and Dr Unger’s sixty-year experiment on his own hands are the two things to cite.

If your knuckles look swollen, get that looked at on its own terms rather than blaming the habit, particularly if the swelling is soft, symmetrical and worse in the mornings.

If your knees click on the stairs without pain, keep using the stairs. Avoiding loaded knee bending because of the noise costs you strength you will want later.

If a joint clicks and also catches, locks or gives way, book an assessment. The mechanical symptom is what matters there, rather than the sound.

If a finger catches and has to be unlocked with your other hand, that is trigger finger rather than knuckle cracking, and it responds well to treatment.

The belief people arrive holding is that a noisy joint is a worn joint, and it changes what they do long before it changes what they feel. It is common to meet someone who stopped squatting in their thirties because their knees clicked, and who now, twenty years on, has a genuine problem going downstairs. The clicking was never the issue. Two decades of avoiding loaded knee bending was.

What testing separates is the sound from the mechanics. A joint is taken through range, loaded, and tested for what actually reproduces the symptom, and in most noisy joints the noise turns out to be unrelated to anything the person came in about. Where it is related, it is usually because the joint is catching at a specific point rather than because it is worn, and that is a mechanical finding with a mechanical answer.

Where a joint is noisy and you are not sure whether it warrants an appointment at all, a free discovery and triage call will sort that out in ten minutes.

Does cracking your knuckles cause arthritis?
No. A 2011 case-control study of 215 people aged 50 to 89 found no association between knuckle cracking and radiographic hand osteoarthritis, regardless of frequency or duration. A doctor who cracked only his left hand for over 60 years found no difference between his hands on X-ray.

What is the popping sound when you crack a knuckle?
It is a gas cavity forming inside the joint. Real-time MRI published in 2015 showed that the sound coincides with a cavity appearing as the joint surfaces separate, rather than with a bubble collapsing. The gas takes around 20 minutes to redissolve, which is why the same knuckle cannot be cracked twice in a row.

Is it bad to crack your knuckles every day?
There is no evidence that it damages the joints. The one study reporting more hand swelling and weaker grip in habitual crackers could not separate the habit from manual labour, smoking and alcohol use, and a later study using ultrasound found no detectable changes. If it is painless, it is not a health concern.

Why do my knuckles crack on their own?
Joints cavitate when the surfaces separate enough for dissolved gas to come out of solution, which happens during ordinary movement as well as deliberate cracking. Tendons also flick across bony edges as they move. Both are normal in a joint that is not painful.

Should I worry if my joints click a lot?
Not if the clicking is painless and the joint moves and functions normally, which describes most noisy joints. Clicking that comes with pain, swelling, locking, catching or the joint giving way is worth assessing, and it is those symptoms rather than the noise that make it worth assessing.

Can cracking your knuckles make your hands weaker?
The 1990 study that reported lower grip strength in habitual crackers also found that group did far more manual work and were more likely to smoke and drink, which plausibly explains the result. The finding has not been replicated in the decades since, and a 2017 study using blinded examination and ultrasound found no attributable change.

When does a clicking joint need to be checked?
When the noise started at the same time as pain, when the joint locks or gives way, when there is new swelling, or when the click happens every single time the joint passes through one particular position. A single loud pop at the moment of an injury also warrants assessment, especially at the knee.