We’ve all experienced it every now and again - the snap, crackle and pop of your knuckles, neck, toes and everything in between. This can be a loud and disconcerting sound often leading to worry that something is wrong - but is this actually the case? What do the sounds mean?
The evidence
Associating joint cracking with a something wrong with the body or an abnormality is a common misconception from clients and health practitioners. No research has shown a definitive link between noise and pathology. In fact, studies have shown that in a cohort of people with no pain, 99% had some sort of knee crepitus.
So why do my joints crack?
Escaping gas
The space between two connecting bones (joint) is encompassed by a capsule filled with synovial fluid. The most common cause of cracking is when a quick stretch of a joint cause compressed gas bubbles within the fluid to pop, which causes a clicking noise. This is why you may not be able to continuously crack your joints as it takes time for the big bubbles to form again.
Friction
The cracking of an ankle on demand can be explained due to the movement of tendons and bones. A soft snapping or clicking sound is also sometimes caused outside the joint when a tight muscle or tendon moves over a bony structure in a certain position.
Rough surfaces
As we age our joints can get noisier as the cartilage goes through normal wear and tear changes. For example in the knee, fluid normally flows through a slightly rough surface under the kneecap and this may cause a fine grating noise.
Don’t crack your knuckles or you’ll get arthritis!
There are many theories that cracking your joints leads to an earlier onset of arthritis. The positive news is that this is completely unfounded and there is no research to support this claim. Habitual knuckle cracking DOES NOT increase the risk for arthritis.
Fun Fact
Did you know? The eland antelope uses knee sounds to display dominance through signalling their body size, age and aggression.
Take home message
We should not see the many sounds that our joints make as a sign of pathology, but as a positive sign, because our joints are mobile and well lubricated. As long as the cracking is not accompanied with pain then it is harmless and you shouldn’t be worried. If joint cracking is accompanied with pain, limited motion or joint swelling, then you can book a FREE assessment at Back In Motion Mentone with one of our expert physiotherapists to get some specific advice for your situation.
References
Castellands J., & Alexrod D. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1004074/
Bro-Jørgensen J., & Dabelsteen T. https://bmcbiol.biomedcentral.com/articles/10.1186/1741-7007-6-47
Robertson C., Hurley M., Jones, F. https://www.sciencedirect.com/science/article/pii/S2468781217300309?via%3Dihub
Author
Nicholas Matkovic
Clinical Associate Physiotherapist