I'm curious, how long do the polyethylene liners last? This is what is used to replace the meniscus in a TKR, and it seems to me the plastic will wear out while the metal won't. So if a revision is necessary, why not just replace the plastic. Sorry, I'm mixing up hips and knees here, but the issue is, I think, the same. I had both knees replaced this year.

FWIW I'm still amazed they can engineer plastic to last for ten plus years, hips and knees. Apparently they irradiate the polyethylene in production and that is what makes it last. Makes no sense to me, but I'm glad it works!