I have the same problem with my ankles, to the extent that they give up on me and i stumble alot because the support is gone and my ankles turn to jelly. I also find if i try and stop them from cracking, my ankle feels like its getting stiffer and stiffer, and gets increasingly more painful, as soon as i let them crack the pain is eased and they feel normal.
Yet no1 seems to have a solution for me, ive spent several months under the hospital and been sent to a department to carry out exericises in a controlled enviroment. I have since been discharged and still have the same problem. I beleive my problem is down to my circulation or as you said athiritis.