I had the thumb joint replaced in my left hand, just as you spoke of about 8 years ago. Mine was called a soft tissue joint replacement, as they take a tendon from the lower arm to make the new joint. I was in a cast for some time with a pin through the joint area, so that it wouldn't get floppy. The pin part was painful, but the joint works and doesn't hurt (except when the weather is about to change, and that isn't so bad. ) Mine was in the cast so long that the second joint doesn't bend any more, but it all works and doesn't limit my mobility at all. For me it was worth it, to get my grip back and the use of my left hand. I'd advise yiou to check out all your options (like it sounds you are) and choose a doctor and occupational therapist who does lots of these. The best of luck to you, and keep us posted.