by Jason Schexnayder, PT, DPT, CMTPT

*Unlike most of our blog posts, this post won’t contain much supporting research. This is because most studies don’t attempt to determine if bodily noises have a direct relationship to pain, injury, or dysfunction. Most studies that do show a relationship between noise and pain/disorder typically involve the temporomandibular joint (TMJ) and the clicking that’s often associated with TMJ disorders. We’ll reference this more later. In other words, most of the information in this blog post is based on clinical experience and opinion and not necessarily supported by clinical research.

“I heard a pop”

Clinically, and even personally, we hear it all the time. Something along the lines of, “I heard my knee pop” or “my back cracked.” In the clinic, how people respond to this varies greatly. At times, they appear unaffected, but others, show clear concern.

So what’s the right reaction?

 

Is this bad?!?!

Is Frank right…is this bad?!?!

As with most scenarios involving the human body, context matters. When you heard the sound, was pain associated with it?

Here are a few straightforward examples of what I mean by context in this case:

  1. Hearing a loud crack as your leg contacts the ground after falling off of a ladder
    • Clearly, the loud noise could be the result of one or multiple broken bones.
    • If that’s the case, then heading to the ER is probably a good option.
  2. Clicking in your jaw as you chew on a burger
    • The disc might be getting caught in-between the articulating bones of the jaw.
    • If you hear a click, and it’s painful, then it’s likely something worth addressing. However, if it isn’t painful, then it might not be anything worth stressing yourself out over.
  3. Hearing a couple of shoulder clicks as you lift up a box to place it on an overhead shelf
    • The shoulder blade is either moving along the rib cage like it’s supposed to or it could be a rotator cuff tendon rubbing under the acromion of the shoulder blade.
    • The shoulder is an incredibly mobile joint and noises are often heard or felt with shoulder movement. As I said before, if the noise doesn’t hurt, then it’s likely nothing to worry about.
  4. Bending your fingers enough to make your knuckles crack
    • Gas bubbles inside of the joint space have distended and burst due to the change in joint pressure, creating the noise you heard and felt.
    • This is normal and nothing to worry about. We’ll discuss this particular topic in further detail shortly.

(Picture Above) A cavitation in a joint occurs when a force is applied to that joint causing the distance between the two bone surfaces to separate. As they continue to separate, pressure decreases inside of the joint capsule leading to the formation of gas bubbles. As pressure drops, the gas bubbles expand and eventually burst releasing the gas from the joint. When this occurs, an audible “crack or pop” can be heard.

 

In general…

If you have a traumatic fall, injury, etc., and hear or feel a pop, click, or crack and experience pain when you do, then it’s LIKELY something you should look into addressing. Even if it is worth addressing, don’t be scared of the sound. And definitely don’t overthink it as negative thinking can adversely affect your pain symptoms even in the absence of injury or disease progression. If you’re performing your regular, daily movements and hear or feel a pop, click, or crack and don’t experience pain, then you probably SHOULDN’T worry about it. The entire purpose of this blog is to dispel any fears you may have about the common and normal noises your body makes while moving.

 

Is it arthritis?

Simply put…maybe.

Knuckle-cracking is a perfect example of a bodily noise associated with a movement that ISN’T harmful.

But what about that age-old saying, “if you keep cracking your knuckles you’ll get arthritis”? Dr. Donald Unger wanted to see if this statement held true. He even won an Ig Nobel Prize for the findings of a case study he performed on HIMSELF. For 50 years, Dr. Unger cracked the knuckles of his left hand at least twice a day and only cracked the knuckles of his right hand sporadically. Now that’s dedication!

The result? No arthritis in either hand.1 

Now, that’s just one man, only manipulating the joints of the hand in an un-randomized case study. So it’s not a study you want to base all your beliefs and opinions on. However, another study was performed involving more participants and whether or not knuckle-cracking is related to the development of arthritis. And, just like the case study, the results were very similar.2 Again, this was only performed on the joints of the hand so you shouldn’t apply this information grossly across all populations and joints.

To my knowledge, manipulating your joints hasn’t been associated with increasing your chances of getting arthritis. There are other risks associated with repetitive manipulation, but in regard to arthritis, I haven’t seen any research that links manipulating joints to the development of arthritic conditions.

 

The Other Big Problem…

The other big problem is that the age-old arthritis quote implies that arthritis is ALWAYS painful. Well, believe it or not, arthritis is a NORMAL part of the aging process and in a lot of instances, NON-PAINFUL. We’ve referenced this in other blog posts. Just because there is an “abnormal” change to a soft tissue or joint, doesn’t mean pain is automatically present. For instance, there was a large systematic review that showed that 19 – 43% of people older than 40 have abnormal MRI findings. The surprise…that 19-43% were asymptomatic. That’s right, some of them even had meniscal tears but DIDN’T experience pain.3 So even if you do develop arthritis in a specific joint/s, that doesn’t mean you’ll wake up in pain every day or won’t be able to go for a walk any time you want.

For all of you that do have arthritis somewhere in your body and you’re performing your normal, daily activities, and hear a noise, if it doesn’t hurt, don’t be afraid, you’re not doing any damage. In fact, regular activity and properly programmed exercise are vital for people with arthritis and overall joint health. We’ll discuss that topic at another time. Just remember, if you hear a noise and it doesn’t hurt, don’t be afraid, you’re ok.

So what are the sounds?

Well, outside of the cavitations that we mentioned earlier, what are those other sounds you keep hearing and feeling? 

Because the soft tissues and bony structures of our bodies are so closely packed together, when we move, those tissues can move against one another in such a way that they create a sound. For example, there is a bony protrusion on the outer portion of your large leg bone (femur) and several tendons of the hip attach to this protrusion. Sometimes, when you rotate the hip, these tendons can move over the edge of that bony protrusion causing a snapping sound and sensation. Similarly, there are several ligaments that help stabilize the ankle. As you squat down these ligaments can get stuck between or slip over the articulating bones of the joint causing a similar snapping sound or sensation.

 

Fuhgeddaboudit…

Instances like these happen often throughout the body…and they’re completely NORMAL. More often than not, the sounds you hear are just your bones, ligaments, tendons, and muscles moving in their normal way across the other structures they have a close relationship with. Like I mentioned before, if it doesn’t hurt when you hear the sound, it’s probably nothing to worry over…so…fuhgeddaboudit!

References

  1. Unger DL. Does knuckle cracking lead to arthritis of the fingers?[Letters]. Arthritis Rheum. 1998;41(5):949-950.
  2. Swezey RL, Swezey SE. The consequences of habitual knuckle cracking. West J Med. 1975;122(5):377-379.
  3. Culvenor AG, Øiestad BE, Hart HF, Stefanik JJ, Guermazi A, Crossley KM. Prevalence of knee osteoarthritis features on magnetic resonance imaging in asymptomatic uninjured adults: a systematic review and meta-analysis. Br J Sports Med. 2019;53(20):1268-1278. doi:10.1136/bjsports-2018-099257