I had a total right knee replacement last year and the prosthesis is now a little loose. how commonly does this happen?

Low: Various sources have published statistics on the long-term revision rates for knee replacement. The long-term revision rate is 2 percent for five or more years. Based on a meta-analysis of worldwide joint registry databases, published in the Journal of Bone & Joint Surgery in 2011, the revision rate is 6 percent after five years and 12 percent after ten years.