No, that's a myth. - Answer: Cracking your knuckles does not cause arthritis. Understanding what physically occurs when you crack your knuckles will help you realize that the "knuckle cracking causes arthritis" theory is actually just a popular myth. - There have been a few studies over the years that considered whether or not cracking knuckles caused arthritis. One study found that there was no increase of hand arthritis among knuckle crackers, however, knuckle cracking was related to hand swelling and lower grip strength. - Another study indicated that while knuckle cracking was not associated with arthritis, it was associated with damage to ligaments that surround the joint and dislocation of tendons. While cracking your knuckles is not linked to causing arthritis, there may be a connection to soft tissue injuries. - http://osteoarthritis.about.com/od/osteoarthritis101/f/crack_knuckles.htm
No, it's proven that cracking your knuckles does NOT give you arthritis. The "cracking" is just air escaping from your joints. It may make your knuckles look thicker, but it will not give you arthritis.
I can only tell you this : I used to beg my niece to stop cracking her knuckles, which she seemed to do 24/7 from the time she was 10 yrs. old. She is now 28 and has severe rheumatoid arthritis. Her fingers are bent and knuckles are very swollen, she cannot wear any rings. The good news is she does have insurance. Her medicine costs $600. A month. Katy will be the first to tell you Please, please stop cracking your knuckles.