As I was reading through your last column, my knuckles started hurting and became restricted in motion. To me, these symptoms, which I've had my whole life, tell me I need to crack my knuckles. I've also been told my whole life that one day my knuckle cracking habit would lead to bigger problems, namely arthritis (which I now have). So, here's my question: Is there a direct correlation between knuckle cracking and arthritis? If so, is there a 12-step program for knuckle crackers like myself who bask in the relief of arthritic pain when our knuckles are cracked?
It would be too easy to make a joke about you being a crack addict (even I have standards), and since I share your habit, it would be hypocritical as well. We are not alone; somewhere close to a quarter of us crack our knuckles on a regular basis, and the percentage rises to nearly 100 percent among those sitting down to pianos on bad television shows. As you probably know, my own chiropractic profession most commonly manipulates joints with a resounding pop, so at the risk of investigating myself out of a job, I've researched your question in depth.
First, it is important to understand the anatomy of the joint itself. Each set of finger bones comes together and is securely strapped by ligaments, which act like industrial strength rubber bands. The inside lining of this flexible package consists of a small sac, or joint capsule, containing the ends of each bone. The capsule is filled with a syrupy lubricating fluid that contains, among other things, dissolved carbon dioxide and nitrogen gasesthink lightly carbonated honey (think, too, of the fortune to be made with this ingeniously sparkling new food product).
Pulling on or bending a joint beyond its normal range of motion causes the popping sound that is as annoying to adults as it is fascinating to children. As the joint capsule is rapidly stretched, the pressure inside drops and the dissolved gas instantly comes out of the lubricating fluid. Similar to popping the top of a soda bottle, this escaping gas creates a bubble inside the joint. As fast as the bubble appears, it collapses upon itself. The snapping sound is made when the thick fluid is sucked into the vacuum left by the suddenly disappearing bubble. A small bit of gas is left floating freely and it takes about 20 minutes to dissolve back into the joint fluid, resulting in the inevitable delay before aggravating someone else.
Arthritis, by definition, is the inflammation of a joint. It includes scores of different conditions and can be caused or worsened by a number of factors including degeneration, infection and your own personal genetics. The worry for knuckle-poppers is that the repeated trauma will result in stiffness, swelling and enlarged joints. The research, as it stands, shows that worry is mostly unfounded.
The small amount of inquiry completed on the subject does not indicate significant arthritic tendencies in the chronic cracker. Not conclusive--but interesting--is a report published in Arthritis and Rheumatism by an allergist who had cracked the knuckles on his left hand at least twice a day for 50 years, but rarely cracked those on his right. Both hands were examined for arthritic changes and none were found. It should be pointed out, however, that more common case studies of overzealous joint jockeys document injuries ranging from dislocations to ligament damage. After reviewing the handful of available studies (pun intended), my conclusion is that over time, aggressive constant knuckle cracking can lead to joint stretching, chronic inflammation and possible hand weakness. But in most cases, the worst outcome may be difficulty removing the childproof cap from that sorely needed bottle of ibuprofen.
You won't need a 12-step program for your type of crack addiction, but if you experience pain from either the joint popping or the arthritis, you should certainly check with your medical doctor or rheumatologist. It's likely your joint discomfort is a result of one of the dozens of arthritic factors unrelated to the habitual snap.
As a chiropractor, I am gratified by these findings, but not truly surprised. Numerous real distinctions exist in the joint mobilization we practice and the knuckle crack. Perhaps the most significant is that the same articulation is not energetically popped several times a day, every day, for decades on end (except, of course, during our four years of chiropractic school). I'm also relieved that I won't have to give up my day job in order to start my carbonated honey distribution center. Now, if I can just find a way to get the bees to eat the Alka-Seltzer ...