Is Knuckle Cracking Harmful?

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Can't stop the pop, at least when it comes to knuckles? Repeated knuckle cracking— or "popping"— has long been thought of as a leading contributor to joint trouble, particularly arthritis [1]. But while the mechanisms behind it aren't perfectly clear, recent research suggests habitual knuckle cracking is not a significant risk factor for arthritis, though it may have several other negative side effects [1].


Photo by Kate Morin

STOP, POP, AND CRACK IT — WHY IT MATTERS
 

Thought the exact mechanisms behind knuckle cracking are still debated, that popping sound is likely not from bone-on-bone contact. To keep them working smoothly, most joints are surrounded by a membrane filled with lubricating fluid and gases. When a joint is “cracked”— an event called articular release— the gases are thought to escape the membrane, causing the characteristic “pop!” sound associated with knuckle cracking [3]. A similar sound may also result when tendons are stretched too quickly over a joint [4]. The same workings lie behind the “cracking” associated with fingers, wrists, ankles, and— in moments of extreme boredom— necks [5].

Though joint cracking is normal and fairly common throughout the body, knuckle cracking in particular has long been blamed as a contributor to painful arthritis [6]. But research suggests habitual knuckle cracking  isn't forceful enough to cause the wear and tear associated with arthritis [7] [8] [4]. In fact, knuckle cracking might actually cause temporary relief in joint pain and reduce symptoms of arthritis, hence the popularity of such crack-ups among chiropractors [7] [11].

Not All It's Cracked Up To Be — The Answer/Debate
 

But while knuckle cracking will probably not cause an inadvertent display of gang signs, don’t get too carried away with that snap, crackle, and pop. Though it's not tied to arthritis, research has linked habitual knuckle cracking with hand swelling and reduced grip strength, suggesting the repeated act might gradually damage soft tissue in the hand [11]. In some cases, the desire to crack could be an attempt to ease ligament stress that is already present, and in some studies habitual knuckle cracking was also associated with other potentially damaging activities like repeated manual labor [13].

With more research on the subject needed, knuckle cracking’s long-term effects remain a bit of a mystery. Though its connection with arthritis is slight at best, instead of cracking away as the main method to relieve joint pain, try incorporating hand exercises to restore finger movement and improve flexibility.

 

Works Cited

  1. Knuckle Cracking and Hand Osteoarthritis. deWeber, K., Olszewski, M., and Ortolano, R. Department of Family Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD. Journal of American Board of Family Medicine. 2011 Mar-Apr;24(2):169-74.
  2. Knuckle Cracking and Hand Osteoarthritis. deWeber, K., Olszewski, M., and Ortolano, R. Department of Family Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD. Journal of American Board of Family Medicine. 2011 Mar-Apr;24(2):169-74.
  3. The audible release associated with joint manipulation. Brodeur, R. Depoartment of Biomechanics, Michigan State University, East Lansing, MI. Journal of Manipulative and Physiological Therapy. 1995 Mar-Apr;18(3):155-64.
  4. Joint cracking and popping: understanding noises that accompany articular release. Proptopapas, MG., and Cymet, TC. Good Samaritan Hospital, Baltimore, MD. Journal of the American Osteopathic Association. 2002 May;102(5):283-7.
  5. The audible release associated with joint manipulation. Brodeur, R. Depoartment of Biomechanics, Michigan State University, East Lansing, MI. Journal of Manipulative and Physiological Therapy. 1995 Mar-Apr;18(3):155-64.
  6. The audible release associated with joint manipulation. Brodeur, R. Department of Biomechanics, Michigan State University, East Lansing, MI. Journal of Manipulative and Physiological Therapy. 1995 Mar-Apr;18(3):155-64.
  7. Knuckle Cracking and Hand Osteoarthritis. deWeber, K., Olszewski, M., and Ortolano, R. Department of Family Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD. Journal of American Board of Family Medicine. 2011 Mar-Apr;24(2):169-74.
  8. Effect of habitual knuckle cracking on hand function. Castellanos J., and Axelrod D. Department of Internal Medicine, Mount Carmel Mercy Hospital, Detroit, Michigan. Annals of the Rheumatic Diseases. 1990 May; 49(5): 308–309.
  9. Joint cracking and popping: understanding noises that accompany articular release. Proptopapas, MG., and Cymet, TC. Good Samaritan Hospital, Baltimore, MD. Journal of the American Osteopathic Association. 2002 May;102(5):283-7.
  10. Knuckle Cracking and Hand Osteoarthritis. deWeber, K., Olszewski, M., and Ortolano, R. Department of Family Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD. Journal of American Board of Family Medicine. 2011 Mar-Apr;24(2):169-74.
  11. Joint cracking and popping: understanding noises that accompany articular release.Proptopapas, MG., and Cymet, TC. Good Samaritan Hospital, Baltimore, MD. Journal of the American Osteopathic Association. 2002 May;102(5):283-7.
  12. Joint cracking and popping: understanding noises that accompany articular release.Proptopapas, MG., and Cymet, TC. Good Samaritan Hospital, Baltimore, MD. Journal of the American Osteopathic Association. 2002 May;102(5):283-7.
  13. The audible release associated with joint manipulation. Brodeur, R. Department of Biomechanics, Michigan State University, East Lansing, MI. Journal of Manipulative and Physiological Therapy. 1995 Mar-Apr;18(3):155-64.

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