Cracked Knuckles

By: Austin Kunz

Background on Statement/Claim

                Robert L. Swezey, MD and Stuar E. Swezey of Los Angeles together on the topic of consequences of habitual knuckle cracking have made the claim: Habitual knuckle cracking in children has been considered a cause of arthritis. A survey of a geriatric patient population with a history of knuckle cracking failed to show a correlation between knuckle cracking and degenerative changes of the metacarpal phalangeal joints.

This statement can be found here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1129752/

                This is something that I have a habit of doing.  It may not be a bad habit but many people will tell you that they often are irritated by the sound.  To better understand what the consequences of this habit could be it is very important to briefly discuss and understand what results when cracking knuckles or other joints in our bodies.  A joint is somewhere where plural bones contact and pivot on one another.  Ligaments in these systems act as a type of rope or hold to keep these bones together.  The joints are lined with a specific type of tissue which is called synovium which has flued that acts as a type of lubricant in reducing friction much like how oil in a vehicles engine works to prevent wear.  Because this is a type of fluid it is possible for bubbles to form within the fluid.  When you are popping your fingers what you hear are those bubbles being forced to pop.  As the bubble is popped the liquid around it replaces where the air was and the synovium fluid becomes more concentrated fluid being a lesser part of air. 

What your joint looks like.

This statement is only one of many statements on the positive or negative effects that popping your knuckles may have both short term and long term.  The effects of this can be related to grip strength, usability of hands, or general deformation of your hands. Many argue that grip strength decays over time as habitual knuckle cracking continues in the lifetime.  General ability to use hands for everyday tasks has been said to be lessened while some would argue comfort is found from doing this and thus does not have an impact on them.  Another largely debated factor involved in this habit is that your hands may become deformed though there is no direct evidence to support this.  As time persists the claims one way or another on this topic seem to shift back and forth.

 Purpose of this blog article

                The purpose of this blog article is to discuss just a few of the many opinions that are had on the subject of cracking knuckles. This article will attempt to bring together some information, studies, and opinions on this subject in a way that will provide readers with a brief overview of the subject.

Evidence for and against the claims made

                One of the many studies that have been done on this subject include a test involving 28 adults living in an elderly home center (average age 78.5) and 28 school aged children (average age 11). Both of these groups are made of both male and female participants.  Those who were involved in this test were selected from large groups only if they were able to recall having a habit of cracking knuckles or not.  This was done to give the most accurate data in relation to this test.  The testing was done by putting participants through two tests: Clinically testing and x-ray examination.  The purpose of doing it this way was to determine both visual and self-aware effects (clinically determined) and those less noticeable (through x-ray imaging).  There have been a few studies involving the way that x-ray imaging was used in this test.  The data in this particular study was unable to find specific evidence that this habit leads to degeneration of important changes relating to joints in the hands. 

Cracking Knuckles is a widely seen habit

                One of the more interesting claims that has been one made by M.D. Dimitrios Pappas.  After having been asked if cracking knuckles can cause arthritis responded by explaining it is not possible for arthritis to be brought on by this.  He didn’t stop there in his explanation however.  He continued by saying that in theory if you were to continue cracking your knuckles when you have arthritis or similar problems relating to joints and ligaments continuing to pop them could lead you to have a higher potential to have ligament injury or creating problems in joints.  This is an interesting take on this often debated topic.  What he is implying is that it will not cause this problem but provided you already have it, it could lead to much worse problems.

                The last study I will mention is one published in Annals of Rheumatic Disease.  This test looked at a group of 300 individuals who had classified themselves as habitual knuckle crackers. The results of this test came our as another mixed test on the subject.  In this group it was found that those who popped their knuckles often were not any more likely to have osteoarthritis when compared to those who seldom did, or never did.  Now for the twist in this discovery.  It was concluded that those who had this habit for a long time were more likely to have hand swelling and reduced strength in their grip.  Though these two points appear to be conflicting it was never concluded one way or another.  The reason for this uncertainty is that they were unable to determine whether cracking knuckles leads to these results, or if those prone to having these issues crack their hands more to relieve pressure.

  

Conclusion

                Many will continue to argue whether or not habitually popping knuckles is bad for you, if it is good for you, or if it plays no significant role in long or short term durations.  This is a topic that often goes back and forth on whether it is good or bad.  In my lifetime I have seen, heard, and read many people arguing both positions on this topic.  As mentioned before it is difficult in many studies to determine whether cracking knuckles causes arthritis, or if those with early development joint and ligament issues are more prone to popping knuckles to release pressure.  Another view to this is that studies will show that while there is no pain or direct relation to issues in your hands there can be painless side effects such as swelling in many cases. In conclusion there will need to be much more studying done on this subject in order to determine the true effects of this in individuals.