There is no evidence that cracking one's knuckles can cause arthritis directly. However, repeated injury of a joint or repeatedly causing it to swell can injure the cartilage and potentially lead to degenerative joint disease.
Studies of people with osteoarthritis in their knuckles show they are no more likely to have cracked their knuckles earlier in life than people who did not develop the condition. However, the bad news is that there is some evidence that people who habitually crack their knuckles have decreased hand function, such as reduced ability to grip tightly.
I have swollen joints in my fingers from osteoarthritis..so..I cannot get any rings over my knuckles and have had to have my wedding ring cut off and I have never cracked my knuckles!!