If you are a knuckle cracker chances are that you have been berated for the habit not because it can be rather irritating (which it can be) but on the assumption that it’s bad for joints of your fingers; and that it will cause arthritis or similar such problems.
It is commonly observed as a nervous tendency among people or as an attention gaining ploy by children.
Also many people do it because they find temporarily improved mobility in their joints after popping.
The fact is that cracking your knuckles is not going to cause arthritis. However this is not to say that cracking one’s knuckles is harmless. In the long run, it is in fact harmful to crack one’s knuckles because constantly doing this can injure the ligaments that support the joints present in the fingers.
Soft tissue damage to the joint capsule has actually been observed in long time knuckle poppers. When the problem becomes exacerbated, it could cause the grip of the person to weaken because the tendons that attach the muscles to the bones may get loosened.
So for dubious pleasure that knuckle popping seems to evoke, it does cause damage in the long run, so really this may be a habit that one can ill afford.