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Why are comments enabled on that web page? What possible good could come from it?
For the same reason they're enabled on Hacker News: frequently, the comments are more informative than the original post.
What was troublesome enough to warrant suppressing them?
Well why do we have comments here either?
I’ve been an insatiable knuckle cracker my entire life. I remember being told all the time it would cause arthritis.

Glad to hear it probably doesn’t.

It does feel like a release to me, which if it is “similar to a popping balloon,” holds some merit.

I learned, to a lot of delight, to crack the “third” joint of my thumb, sometime in high school. It’s something I often spontaneously do.. anyone I’d be holding hands with. They invariably get a little creeped out. Then ask me to do the other one.

Heading incorrect, should be “mostly” harmless.

(Also, my wife specialises in helping a subset of the population for whom cracking the knuckles is far from harmless... i suspect she’d be furious at this headline.)

OCD I reckon?
Hypermobile (and hEDS) population and related connective tissue disorders.
What is that subset?
From the article:

> Cracking the knuckles is probably harmless. Although there have been occasional reports of dislocations or tendon injuries from overly vigorous knuckle cracking, such problems seem very much to be the exception and not the rule.

I'd guess that "overly vigorous knuckle cracking" manifests as a symptom in people with underlying mental health conditions.

> occasional reports of dislocations

(My wife treats hypermobile people... dislocations are prevalent there, in many many joints.)

> > occasional reports of dislocations

> (My wife treats hypermobile people... dislocations are prevalent there, in many many joints.)

I belong to a very different subset: my finger joints (typically the last joint, nearest the tip, as opposed to the knuckle near the palm) crack very easily, often involuntarily (particularly in cold weather), or with a minimal amount of opposing muscular 'flex' while curling my fingers.

The sound they make is a higher pitched click or snap, like a breaking twig, compared to the typical 'pop' of a cracked knuckle (which I can't actually do).

I haven't ever come across anyone else whose fingers do this, either voluntarily or involuntarily.

Is there a name for this?

You must be very special :). I don’t know why that would. My googling said it could be rheumatoid arthritis:

> Rheumatoid arthritis

Popping joints can also occur with forms of inflammatory arthritis, such as rheumatoid arthritis.

High-pitched popping sounds from joints are more likely to be from inflammatory arthritis. Lower sounds can be from either inflammatory or noninflammatory arthritis, although this may be hard to distinguish

From: https://www.medicalnewstoday.com/articles/325341#what-condit...

...but I don’t think this one symptom could be nearly enough to be evidence of that.

Could just be specific to the joint architecture. Everyone is a little different.

Thanks for the informative reply.

I wonder, the terms we're using to describe sounds are a bit subjective (especially as they are on a continuum). Is there any medical site that gives representative examples of the various joint sounds?

Hypermobile (and hEDS) population and related connective tissue disorders.
This is an article where the HN policy of using the actual article headline would be particularly helpful. The article does not state what its HN headline presently asserts, rather it says: "Cracking the knuckles is probably harmless."
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I also enjoy cracking my toe knuckles and ankles. I'm particular, popping my ankle is often the only way to relieve pain from standing for a long period of time.
Yikes - never heard about ankles before. Are you sure that’s not a relieve and the cause at the same time?
Give your body some more mileage, you will get there.
After I broke my ankle (crushed between trees), they had to re-attach part of one of the bones (the ball part that goes into the socket) with 3 temporary pins. Once the pins were removed and I started walking again (after lots of physio), my ankle would swell up to the point where it would literally not move without cracking it first. Cracking would also instantly relieve 90% of the pressure and pain in the ankle for at least an hour or two, it was marvellous.

I've regained all of the extension motion and probably 70% of my retraction motion (moving toes towards knee), but only about 30% of the muscle strength. Unfortunately it still swells up after long periods of standing or hiking but I'm rarely able to crack it anymore, and really wish I could on those bad days.

Toes, ankles, wrists, even my knees.
if i dont pop my kneecaps before running i get injured.
Knuckles, wrists, elbows, toes, ankles, knees. My wife hates it, I can't live without it.
I do all of them too. And sometimes, I crack whatever joints or bones are there in my neck and spine - every now and then, one of them locks up and makes the same kind of sound as knuckles when forced.
I can crack my jaw. What about when you bend your fingers at the joints, I can crack those too.
As a knuckle cracker myself, it's certainly relieving that there's no evidence of degenerative harm even though there are apparently a few cases we'd probably see it if it occurred. However, the reduced grip strength (admittedly small N) is notable. If that is a change that occurs on a relative short timescale (i.e., starts when you start cracking your knuckles and stops when you stop), it's potentially feasible to study with an RCT. I bet you could even estimate compliance with knuckle-cracking instructions using something like a FitBit.
does this paper account for the externalities?
Something that comes up every time I hear a discussion about this: Just cracking your knuckles is different from actually overextending your knuckles. The latter is definitely harmful.
Two studies supporting the claim of harmlessness are cited: the first analyzes a single subject; the second analyzes 28 subjects with no control group (it's looking at correlation). Doesn't seem very rigorous to me.
this is the "rigor" of the "larger study" of 28 was studied this way... :- "Twenty-eight patients (residents of a Jewish home for the aged) who were able to recall whether or not they cracked knuckles (and in the case of a positive response were able to demonstrate a KC maneuver) were examined clinically and by x-ray. "
Knuckle cracking can become a bit of an addiction, especially so in some circumstances. At some point I had grown an habit to crack my neck too, among other body parts, until I almost felt it "snap" once, with a numbing sensation following, and have never ever tried or attempted to do so again except the one off stressful moment without realizing it. It may be "harmless", but as with every other thing it can definitely grow to be a threat to one's health.
It's definitely addicting. I've found that once I know I can crack a knuckle I keep cracking it. I didn't used to crack the last (distal) knuckle on my fingers and I remember one time in high school a friend of mine grabbed my hand in class and cracked it. The first time it really hurt but ever since then I crack all those knuckles as part of my "routine".