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I've suspected that cartilage regenerates ever since I learned that long term knuckle cracking doesn't cause long term damage, despite the audible crack coming

I've suspected that cartilage regenerates ever since I learned that long term knuckle cracking doesn't cause long term damage, despite the audible crack coming from cavitation (which can be very destructive to things like ship propellers, eroding the metal over time.) If it didn't, my hands would probably be crippled by now.

hanniabu 7y ago
I thought it was known that cartilage can regrow but it's just at such an incredibly slow pace due to lack of circulation that you can effectively say it doesn't grow? Edit: after some googling I found this result > age 15 or 16 would be about the average age for bones to stop growing, so from that point on, there is no collagen regeneration in the cartilage. Your body, on its own, cannot regenerate the cartilage it loses in its adult years. https://regenexx.com/blog/does-cartilage-heal-on-its-own/ https://regenexx.com/blog/does-cartilage-heal-on-its-own/
- thatcat 7y ago
  That source is over simplifying; some bones and cartlidge are known to continue growing in adults - the jaw and ear lobes for example.
- convery 7y ago
  That does sound weird considering how many athletes develop issues later in life due to build up of cartilage. My friend, 66, for example did boxing in his late 20's and started getting issues in his 50's due to nasal-blockages, to the point where he now needs to drill away some of the cartilage to get rid of migraines and such..
  - rjsw 7y ago
    Cauliflower ears in rugby players would be another example.
    - targonca 7y ago
      Cauliflower ears are caused by the ear cartilage dying off and being replaced by fibrous scar tissue. That's definitely not cartilage overgrowth.
  - joncrane 7y ago
    True hyaline cartilage cannot "build up." The good stuff (intra articular) is a precious resource that you can only lose, not gain. The cartilage in your nose and ear are different, and besides, the stuff that's blocking your boxer friend's nose, and causing cauliflower ear is not really cartilage. It's fibrous growth which has a blood supply. It's your body trying to replace real cartilage with a poor substitute.
    - ChrisBland 7y ago
      Exactly, not all cartilage is the same. The good stuff doesn't come back unfortunately.
- kevin_thibedeau 7y ago
  They're selling a product that depends on you not knowing the truth. Medical hucksters routinely lie with facts.
- MisterOctober 7y ago
  I learned a little about this topic recently after a bad knee injury from running [torn meniscus] -- Blood supply does have a lot to do with healing-or-not -- taking the meniscus as an example, about 30% of the meniscus has a blood supply, the rest does not, so that if the injured part is of that 30%, it can actually heal, whereas if not, they can only clean it up and stitch it together like a rag doll --- [for the curious : I got lucky and my injury healed tolerably well on its own sans surgery]
sachdevap 7y ago
Does knuckle cracking have anything to do with cartilage? I suspect it is not a related process. https://www.medicalnewstoday.com/articles/259603.php https://www.medicalnewstoday.com/articles/259603.php
throwaway_law 7y ago
I believe the prevailing thought on the audible cracking is that it is the bubbles in the fluid between cartilage and nothing to do with the cartilage itself.
- catalogia 7y ago
  That's my understanding. But the collapsing bubbles are next to the cartilage I believe, and it seems to me should therefore be causing cavitation erosion. When cavitation erodes a boat's propeller, the cavitation is occurring in the water next to the propeller, not in the propeller itself. https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage
- mikelyons 7y ago
  Here's a video of it happening on live x-ray: https://www.youtube.com/watch?v=ZyUjH2FmRLE https://www.youtube.com/watch?v=ZyUjH2FmRLE Quite creepy
s_y_n_t_a_x 7y ago
The cracking sound is caused by nitrogen bubbles, not by cartilage breaking. Cracking your knuckles is safe as far as we know, if anything it probably helps because you're stretching your ligaments.
- mikelyons 7y ago
  Doc told me your tendons can end up taking up the slack, which can cause other issues

hanniabu 7y ago

I thought it was known that cartilage can regrow but it's just at such an incredibly slow pace due to lack of circulation that you can effectively say it doesn't grow? Edit: after some googling I found this result > age 15 or 16 would be about the average age for bones to stop growing, so from that point on, there is no collagen regeneration in the cartilage. Your body, on its own, cannot regenerate the cartilage it loses in its adult years. https://regenexx.com/blog/does-cartilage-heal-on-its-own/ https://regenexx.com/blog/does-cartilage-heal-on-its-own/

thatcat 7y ago
That source is over simplifying; some bones and cartlidge are known to continue growing in adults - the jaw and ear lobes for example.
convery 7y ago
That does sound weird considering how many athletes develop issues later in life due to build up of cartilage. My friend, 66, for example did boxing in his late 20's and started getting issues in his 50's due to nasal-blockages, to the point where he now needs to drill away some of the cartilage to get rid of migraines and such..
- rjsw 7y ago
  Cauliflower ears in rugby players would be another example.
  - targonca 7y ago
    Cauliflower ears are caused by the ear cartilage dying off and being replaced by fibrous scar tissue. That's definitely not cartilage overgrowth.
- joncrane 7y ago
  True hyaline cartilage cannot "build up." The good stuff (intra articular) is a precious resource that you can only lose, not gain. The cartilage in your nose and ear are different, and besides, the stuff that's blocking your boxer friend's nose, and causing cauliflower ear is not really cartilage. It's fibrous growth which has a blood supply. It's your body trying to replace real cartilage with a poor substitute.
  - ChrisBland 7y ago
    Exactly, not all cartilage is the same. The good stuff doesn't come back unfortunately.
kevin_thibedeau 7y ago
They're selling a product that depends on you not knowing the truth. Medical hucksters routinely lie with facts.
MisterOctober 7y ago
I learned a little about this topic recently after a bad knee injury from running [torn meniscus] -- Blood supply does have a lot to do with healing-or-not -- taking the meniscus as an example, about 30% of the meniscus has a blood supply, the rest does not, so that if the injured part is of that 30%, it can actually heal, whereas if not, they can only clean it up and stitch it together like a rag doll --- [for the curious : I got lucky and my injury healed tolerably well on its own sans surgery]

sachdevap 7y ago

Does knuckle cracking have anything to do with cartilage? I suspect it is not a related process. https://www.medicalnewstoday.com/articles/259603.php https://www.medicalnewstoday.com/articles/259603.php

throwaway_law 7y ago

I believe the prevailing thought on the audible cracking is that it is the bubbles in the fluid between cartilage and nothing to do with the cartilage itself.

catalogia 7y ago
That's my understanding. But the collapsing bubbles are next to the cartilage I believe, and it seems to me should therefore be causing cavitation erosion. When cavitation erodes a boat's propeller, the cavitation is occurring in the water next to the propeller, not in the propeller itself. https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage
mikelyons 7y ago
Here's a video of it happening on live x-ray: https://www.youtube.com/watch?v=ZyUjH2FmRLE https://www.youtube.com/watch?v=ZyUjH2FmRLE Quite creepy

s_y_n_t_a_x 7y ago

The cracking sound is caused by nitrogen bubbles, not by cartilage breaking. Cracking your knuckles is safe as far as we know, if anything it probably helps because you're stretching your ligaments.

mikelyons 7y ago
Doc told me your tendons can end up taking up the slack, which can cause other issues