Cracking your knuckles does not cause arthritis, though most would argue that it does. That popping sound when cracking your knuckles is basically gas bubbles forming and bursting in the fluid of your joints. This is completely normal, and it doesn't hurt your bones or cartilage. Scientists have researched this for many years, and no research has been found to connect the cracking of knuckles to arthritis. However, while it does not cause arthritis, cracking them too often may have minor effects. Various studies say that people who crack their knuckles frequently might have slightly weakened grip strengths over a period of time. That means your hands might not be that strong in performing tasks like opening jars or just carrying heavy things. Also, frequent knuckle cracking may annoy the tissues around the joint, causing some swelling or pain. Knuckle cracking does not cause injury; however, some people do find the associated sound rather repulsive, and so consideration of when and where the behavior occurs is appropriate. So, in the end, if you like popping your knuckles, you have nothing to fear from arthritis, but if your hands start aching, then you may want to cut back a little bit.