What’s That Sound? SNAP, CRACKLE, POP

It’s a question most orthopedic surgeons get asked on a daily basis: “My joint pops…is that normal?” Like most things in life, if it’s not broke (or hurting), don’t fix it. An acute injury resulting in an audible “pop” is different from a situation such as a hip “popping” for years. Popping, cracking, or crunching of joints is quite common and often nothing to be too concerned with, especially if it is not causing discomfort or affecting one’s activities. Here are some need to know tidbits on joint popping and cracking.

What Causes This?

• Numerous theories and causes exist including ligament stretching, tendons snapping, nerves subluxing, or bubbles forming within the joint. A recent study investigated the bubble theory using MRI videos to propose the mechanism by which “cracking” your knuckles results in a negative-pressure event which draws synovial fluid into the joint, thus leading to the subsequent pop. Why does it feel good to crack a knuckle? Thoughts are that the pressure phenomenon within/around the joints stimulates certain receptors which allows for muscles to relax. Another theory suggests natural painkillers (endorphins) are released with such activity, which may explain why it can be a difficult habit to break.
• Other things must also be taken into account when discussing the cause of noise around a joint, such as prior injuries, surgeries, hardware/implants around the joint, and other accompanying symptoms. It is quite common for someone who injures their ACL to feel or hear a “pop” from the ligament rupturing. This must be taken in a different context from the chronic, painless popping that someone may experience around their knee cap from soft-tissue issues.
• Lastly, arthritis can commonly be accompanied with crunching or cracking sensations and as long as it is not resulting in increasing pain or swelling, it is something that can be observed. Some older style knee/hip implants may result in noises (e.g. squeaking), and if you were experiencing this, it would likely be best to visit with your orthopedic surgeon to check the status of things and make sure the components were not wearing out in an abnormal fashion.

Should I Be Concerned?

In general, if the popping/cracking around a joint is not causing pain or swelling to occur or interfering with your function or activities, there shouldn’t be much concern. Studies have looked at whether or not cracking your knuckles would lead to arthritis, and to date, no such correlation has been shown. That said, it is generally recommended that one not perform such activities too frequently or on purpose as there have been reports of joints/knuckles becoming loose from habitual cracking. In addition, habitual knuckle crackers have been shown to develop hand swelling (not from arthritis) and decreased grip strength which can lead to decreased manual function. Nodules can also form from such activity, and this may cause cosmetic concerns for certain patients.

Common Areas to Experience It

Any joint can develop it, but perhaps the most common areas to experience it are in the hands, knees, spine, and shoulders.

• As already mentioned, knuckle cracking is a common occurrence.
• With regards to the knee, the anterior aspect often experiences popping/crunching from the patellofemoral joint (knee cap). This can be from mild softening of the joint, but most of the time it is from soft-tissues in the area (e.g. plica, fat pad) that simply release themselves during motion.
• Similar to the knuckles in the hand, the facet joints and other muscles/ligaments around the spine are prone to popping.
• The spine is a complex unit with numerous muscles, joints, discs, and ligaments contributing to its stability. Chiropractors make a living out of therapeutically popping, cracking, and aligning patients’ backs, so why would you get too concerned with your back popping if you’re not having any discomfort with it?
• Lastly, the AC joint of the shoulder almost always develops arthritis, but rarely causes too much pain or functional limitation. Popping over this portion of the shoulder with no other symptoms is quite common. On the contrary, patients with symptomatic instability or arthritis in the shoulder joint proper will almost always have pain or issues with their function accompanying this, and would thus be treated differently to the above mentioned scenarios.

Summary

Painless popping around joints is an issue that one should hardly ever get too concerned with. If popping occurred from an acute injury or there were other symptoms being experienced in addition to it, then a visit with your orthopedic surgeon would be recommended at that point. Otherwise, keep up what you are doing and don’t let some painless noise around a joint stress you out.

Trevor Born, MD is an orthopedic surgeon with a specialty in sports medicine. At Sarasota Orthopedic Associates our commitment is to get our patients back on their feet, back to work, back in the game, and back to life. We have four convenient locations and offer same day appointments when needed. Visit our website at www.SOA.md or call us at 941-951-2663 for an appointment. Appointments may also be made via our website.