crackling of any joint in the beginning you feel relaxation, if it becomes habit it is injurious to joint tissue,avoid doing it

Hello, cracking of knuckles is very common. It involves that you bend your joint  either ways in order for it to crack. If it becomes a habit then you will try to crack it often and may cause excessive load/pressure on the joint and this might cause damage to your ligaments and capsule around the joint. As they say, anything in excess is not good !