Before you do this, have you properly investigated appliance therapy and otherways you could address the issue, check out the discussions that were written in one of my blogs ..I can't recall anyone who had a possitive thing to say about their surgical experience..
http://www.medhelp.org/user_journals/show/65715
I am not saying that you don't need a new joint, maybe you do , but shouldn't they first extablish the correct position before they place the new joint? Another words, if in this position you destroyed your god given joint, what's there to prevent you from doing the same thing to the artificial one? just somehings to think about..Read all the entries in the discussion board of the blog.