Ed,
Welcome to the forum. I had BTKR on 6/18/08. I go back for my 1 year check and baseline xrays for my spacers on 6/19/09. Then it is every 2 years for new xrays to keep tabs on the wear and tear of the spacer. When the spacer needs replacing, they will do that..... I expect it to be a good long time!
I hope you have been working on your upper body strength, and are looking forward to getting your life back. I went downhill skiing again this past February. It was exhilarating!
You will go thru all the emotions of being: scared, nervous, excited, anxious, depressed, and finally rewarded by your hard work at PT.
All the best of luck to you!