Thanks for the reply. I’ve wondered about the plastic as well and will be asking about it. I have had metal in my other knee since 1995 without any issues. As of now, the surgeon is going to put me on an a 6 day course of oral steroids to see how the knee responds. However, I know that it can’t solve the issue long term. I’ll be seeking a second opinion as well, despite the surgeon telling me he’s going to confer with another surgeon.