Does cracking your knuckles cause arthritis?

Ever since I was a little kid, I have cracked my knuckles as a nervous habit. I’m not a nail biter, nor a hair twister; I push down on the joints of my fingers until I hear that satisfying “popping” sound that calms my nerves. Because of this habit, I have been told by everyone I know countless times that I will develop large knuckles or arthritis in my fingers later on in life. After several years of cracking my knuckles, I have yet to develop swollen fingers or any pain in my joints which leaves me to question whether there is a correlation between cracking your joints and developing arthritis.

Image result for cracking knuckles
Image found here.

The “popping” sound we hear when we crack our knuckles comes from the bursting of gas bubbles located in the synovial fluid which surrounds our joints. This occurs when we press on the joints or pull and stretch the bones apart (Harvard Health Publications). Research shows that anywhere between 25 and 54 percent of the population cracks their knuckles, the habit being more common among males than females. Because of this phenomenon, several studies have been done to find out whether this habit creates any risks to our bodies (Medical News Today).

One experiment was published in 1998 by Dr. Donald Unger. He reported that he used his right hand as the control while he cracked the knuckles on his left hand twice a day for 50 years. It is estimated that his left knuckles were cracked up to 36,500 times. After the 50 years it was found that neither hand had arthritis nor were there any significant differences between the two hands. This study concluded that knuckle cracking did not cause arthritis (Medical New Today).

However, while cracking your knuckles may not lead to arthritis in your hands, it may correlate with swollen fingers and a weak hand grip. Further studies conclude that 84 percent of chronic knuckle crackers develop swollen joints later on in life compared to a mear 6 percent of non- crackers (Samuel Merritt). Now, does this mean that cracking your knuckles directly causes swollen joints and decreased hand strength? Or is there another variable that creates these harmful effects? Perhaps many knuckle crackers are often people who use their hands a lot such as manual laborers, typists, writers, or painters. This would therefore mean they feel the need to stretch or “relieve” their fingers more often and so, they crack their knuckles. This wouldn’t mean that the knuckle cracking directly causes the swelling or weakness, it would be due to the confounding variable such as their occupations.

Another idea to consider would be the idea of reverse causation meaning that arthritis and swelling of the joints causes people to crack their knuckles. This idea obviously makes no sense and is impossible therefore, it can be ruled out. As always, chance is a possibility. It may be a complete coincidence that people who crack their knuckles do or don’t develop arthritis or swollen joints.

In conclusion, studies have reported that cracking your joints does not lead to the development of arthritis. It is still undecided whether it causes swelling and a weakness of grip in the hands but there is a correlation between the two. For now, I would say that cracking your knuckles creates no real harm to your body and may just be an annoyance to the people around you so, continue to “pop” away.




14 thoughts on “Does cracking your knuckles cause arthritis?

  1. Anna Josephine Wisniewski

    This is an awesome post. Cracking knuckles is actually one of my pet peeves just because the sound freaks me out a little. Personally, I am a huge nail biter and CAN NOT stop. It’s insane.

    I like how you had numerous studies on the topic. In particular, the one about the man cracking only his left knuckles for 50 year was so interesting! I also thought it was great how you pointed out possible confounding variables as to why someone would have a weak grip. I found an article on steps to take to stop cracking your knuckles:

    I think the next thing to look at here would be if cracking knuckles does not directly cause arthritis in our hands, what is the main source of the arthritis? Also, do people with arthritis tend to be people who cracked their knuckels? Just some things to think about! Overall great post.

  2. Liz Galante

    I really enjoyed reading this blog because cracking my knuckles is a habit that I want to break more than anything. The main reason is because I mainly do it when I either feel awkward in a situation or I am nervous- doing this I am giving away to whoever I am with a sign of nervousness which I hate. However, I have to admit I definitely think I have caused my fingers to have pain and swollen fingers from the amount I crack them so it was shocking to me to see that cracking your knuckles and arthritis didn’t have much correlation but thought it was interesting to do further research.

  3. Alexander Mark Schaefer

    When I was little I’d always crack my knuckles, and always my grandmother would yell at me to stop because she thought I’d get arthritis and have abnormal knuckles. I stopped up until about freshman year where I’d crack my knuckles before a match. I have felt no swollen fingers, aches at the joint, or change in size of my knuckles. I’m intrigued by the fact that this can lead to weaker grip strength. After reading this article I wanted to find out what actually caused arthritis, and the following article helped me understand more.

  4. Olivia Mei Zhang

    I always wondered if arthritis was caused by cracking knuckles! However, after reading this study, I’m surprised that there is little to no correlation between the two. Is it possible that this happened by chance? Are there multiple studies that have happened that support this conclusion? In this case, scientists would fail to reject the null hypothesis that there is no correlation between knuckle cracking and the development of arthritis. This article: also supports this conclusion, so maybe it is true.

  5. Mallory Dixon

    As I was reading this post I subconsciously started cracking my knuckles. My mom hates the “popping” sound every time my sister or I would crack any part of our body and she would always tell us that we would end up with arthritis and our hands would feel like an 80 year old’s when we are only in our 40’s. I always thought I was damaging something because I didn’t think it was normal to hear a cracking or popping sound every time I put pressure on my hands. Does this post also apply to cracking other parts of your body? Like your back, neck, or even ankles? Or does it only apply to the knuckles and joints in your hands? I’m happy to now know that all the times I cracked my knuckles I was never doing as much damage as I thought.

  6. Victor William Gregory

    Hey Avery!
    I really like this topic. I wish I had thought to blog about it. I found it interesting that Dr. Unger was able to only crack the knuckles on one of his hands for 50 years. I have to crack them on both hands. My mother has always told me the same thing, that it will cause my to have arthritis when i’m older. Around the age of 16 I began to develop pain in the joints of my hands and wrists. Subsequently, my mother blamed it on my knuckle cracking. However, Arthritis tends to run in my family so i’m almost certain that is the cause. Furthermore, at Thanksgiving i asked my uncle, who is a physical therapist, if he believed that cracking my knuckles would cause this. He told me and my mother that it would not cause arthritis, but he also said cracking my knuckles achieves nothing. We like to believe that it provides some feeling of pressure relief, but in reality it does nothing but satisfy our mental desire to hear the crack. I think knuckle cracking should be looked at deeper from a psychological view point. Something could be said about how a person feels before and after they have cracked their knuckles. I have attached a link to an article that discusses part of my thought.

  7. Rachel Sara Anton

    I really like this post! I was amazed by the study focusing on one man who cracked his left knuckles for fifty years…that’s insane and definitely proves something; however, to completely rule out the null hypothesis, you’d need much more evidence than just one man’s personal experiment. I think it’s helpful that you included a description of the physical occurrence that takes place when one cracks his/her knuckles. This takes away from the whole stigma of the word “cracking” considering it sounds painful and dangerous. I also had a revelation that maybe reverse causation could be possible in some cases. Could arthritis cause knuckle cracking through a confounding variable of stress? Considering that stress and anxiety are often a factor of knuckle cracking, this could be an interesting thing to study. Check out this study that actually goes as far to say that knuckle cracking is good for you.

  8. jgb5274

    I just recently started cracking my knuckles not thinking it would be habit forming, but it is. My parents get mad at me when I do it and tell me to stop because they think it will cause Arthritis so this article was very pleasing to read to find out it has yet to. I do not think their is anything wrong with it since it is so easily done. I feel like if it was extremely bad for you then it would hurt doing so. It does scare me that my fingers will permanently swell by cracking them. So far, it has done nothing to the size of my fingers and it could be a total myth just to get people to stop.

  9. Zachary Cope

    I loved this post because this debate has been ongoing ever since I can remember, so I was glad I got further insight about it. I’ve always been a knuckle cracker as well. Whenever I find my self in a boring situation, I always go right to the knuckles and start to crack them every which way: down, left to right, right to left… yeah as you can see it’s a bad habit, and probably really annoying to those around me. My dad used to tell me when I was younger that cracking my knuckles would give me arthritis, but that never seemed to phase me from doing it, I just figured that I was a kid and It would never happen to me. I’m also the kind of person who is very hard to persuade on many topics that haven’t been proven, so when people would mention the idea of me getting arthritis, I would give them my doubts and continue with my day, but I liked reading up on the different experiments these researchers conducted and how they came to conclusion that there was no correlation to cracking your knuckles and arthritis. However, they did find that most people experienced swollen knuckles later on in life, so that kind of irritates me on some level. Anyways, I’ve always wondered why it was that our knuckles cracked in the first place. Here’s an interesting article explaining the science of what happens when your knuckles crack.

  10. Anna Strahle

    I have always been the one in my friend group to constantly crack my knuckles. I took piano for several years, and whenever I was at my lesson and would even reach to push my knuckles down and hear them crack, my teacher would quickly grab my hand and yell at me to stop. She would say “do you want to have beautiful hands that you are able to play the piano with”. At the time I hated taking piano lessons so I wouldn’t answer, but my bad habit continued despite her efforts to try and scare me. Over the years, my friends and family would yell at me to stop every time they heard the “popping” sound, telling me that I would eventually have arthritis. One day someone told me that it was only the noise of gas bubbles in our bones, and I was overjoyed that I was no longer at risk for arthritis. Your blog opened my eyes that there still may be a few risks to my satisfying habit, so maybe I should reconsider trying to stop, but it will definitely be easier said than done.
    If you’re addicted to cracking your knuckles too, here’s an article that has some helpful tips on ways to stop:

  11. Jarrod T Skole

    I have been cracking my knuckles for so long now I can’t even remember when I first started. People have always told me that the more I crack my knuckles, the better chance I have of getting joint pains and arthritis, but I never listened to them. Its funny you put that study of the man who only cracked one hand and not that other because I found that study a few weeks ago online and was thrilled to see that there was no real problems with his knuckles after so long of cracking them. I agree with your confounding variable on how people could get arthritis while also cracking knuckles, but have you ever thought that maybe cracking knuckles might have the opposite effect. Maybe the more you crack your knuckles, the better chance it is for you to not get arthritis. I would be interested to see a study done testing that and see if cracking knuckles is actually beneficial for you.

  12. Julia R Martini

    This was a very interesting post! Growing up, I’ve heard the same false theory as you! I concluded that it was false since my one friend who cracks her knuckles at least 100 times a day still doesn’t have arthritis but I liked reading about the science behind why this is false. The reverse causation really makes sense! I think it could be a valid argument! I tried finding an article to see if arthritis does in fact cause knuckle cracking but I couldn’t find one. I did find this article from Harvard University. It’s basically a small review to what you stated but it includes why cracking your knuckles is still bad for you.

  13. Margaret Marchok

    Avery- as someone who cracks her knuckles all the time, I feel your pain with getting told a million times that I am giving myself arthritis. I always believed it, which is why I found the study you included to be very interesting. First of all, I find it so impressive that Dr. Unger was able to remember to crack his knuckles every day for 50 years. I don’t even remember to eat breakfast every day, yet he remembered to crack his knuckles. Anyway, it was shocking to see that even after cracking his knuckles so much he showed no signs of arthritis. I thought of another confounding variable that may be leading to arthritis in patients- genes. Arthritis can actually be hereditary. If someone’s parents has arthritis, they are actually at a greater risk for getting it as well. This article answers some good questions about arthritis and genetics- Enjoy!

  14. Valerie Lauren Murphy

    This is an interesting post. I’ve been cracking my knuckles since I was little. I started because I saw my dad always doing it (he owns a construction business and was typically using his hands while on a job). My other family members, however, told me that if I continued this habit, I would surely get swollen knuckles or develop arthritis. Initially, I was concerned and would stop temporarily, but my worries would pass and I would continue to go on cracking my knuckles. I’m glad that so far it’s been scientifically proven that my habit won’t cause arthritis. Although arthritis hasn’t been proven to be genetically passed down, a person related to someone with it would be at a greater risk of developing the disease. So maybe it’s possible that people who are predisposed to arthritis and crack their knuckles speed up the process causing an earlier onset of the disease, which could possibly account for the correlation you mentioned.

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