I realize this post is old but wanted to comment. I had a TKR back in 2008. I am big 6' 4" 260 lbs. I ride about 3000 miles a year with about 100,000 ft. of climbing. Was at Dr. for routine checkup and some xrays and was told that the plastic insert was almost worn out. I am going to continue to cycle and am researching a revision specialist. I am led to think that possibly replacing just the plastic piece is an option.
My hope is to find a specialist that also enjoys cycling because I do not want to give up cycling. How to achieve this is not going to be easy. Going in I knew with my size and activity level knee would not last as long as normal but am shocked to find out I wore it out in 7 years