Posts Tagged ‘Synovial fluid’

Have you ever had someone tell you that before? I get asked questions like this all the time in my practice. People who crack their hands, spine, knees, feet etc ask me if they are causing damage to themselves by cracking their joints. I always ask them if there is any pain/numbness/tingling associated with the crack. If they say no, I tell them not to worry about it as there is no evidence that says cracking is bad for you or will give you arthritis. (Authors note: The studies I am referring to were only conducted on the hands and I don’t know of any literature that addresses this question for any other part of the body).

In short, there are a few reasons why joints “crack”. It could be because of a tendon snapping over a bone (snapping hip syndrome). Or it could be a bone moving over another bone (snapping scapula syndrome). A true joint crack occurs when joint surfaces of an encapsulated joint (say a facet joint in the spine) are separated. This in turn creates a reduction in pressure within the joint cavity. In this low-pressure environment, some of the gases that are dissolved in the synovial fluid (which are naturally found in all bodily fluids) leave the solution, making a bubble,,which rapidly collapses upon itself, resulting in a “clicking” sound. This process is known as a cavitation and is the same sound you hear when a physiotherapist, chiropractor etc manipulates your spine.

The common advice that “cracking your knuckles gives you arthritis is not supported by any evidence to date. A 2011 study from the Journal of the American Board of family Physicians examined the hand X-rays of 215 people (aged 50 to 89) and compared the joints of those who regularly cracked their knuckles to those who did not. The study concluded that knuckle-cracking did not cause hand osteoarthritis, no matter how many years or how often a person cracked their knuckles. “The prevalence of OA in any joint was similar among those who crack knuckles and those who do not”

In 2009 a doctor by the name of Donald Unger won a Nobel Prize for a study of one participant…HIMSELF! He cracked the knuckles of his left hand every day for more than sixty years (that’s dedication), but he did not crack the knuckles of his right hand. In the end, no arthritis or other ailments formed in either hand after 60 years of cracking his left hand.

So all in all, cracking the hands is not a problem, and there is nothing that would lead me to say stop doing it. However (and it’s a big one)…If you have ANY pain or limitation with joint cracking, it is best to seek consultation with a health care professional. You may have a joint instability or hypermobility which may cause you problems down the road if not properly addressed.

Have a great week!

Jesse Awenus B.A Hons (Kin), MSc.PT
Registered Physiotherapist

DeWeber, Kevin, and Rebecca Ortolano. “The Journal of the American Board of Family Medicine.” Knuckle Cracking and Hand Osteoarthritis (2011): n. pag. Knuckle Cracking and Hand Osteoarthritis. Web. 22 July 2012. <http://www.jabfm.org/content/24/2/169&gt;.