I was a bit curious too, about how it all worked. There were two different doctors doing the TKR at the hospital near me. Before surgery all the patients attended a class covering exercise, procedures, in-home physical therapy, outside physical therapy, etc. It was presented as a treatment package, regardless of what insurance anyone had, and we were just told insurance would cover it. And it did! Walker, commode, shower chair, and more were available on loan for 90 days. The ice machine was sent home to keep. I had $10 co-pays when I extended my PT, but otherwise I only had small charges for medication and a couple of $10 co-pays for follow-up visits. I just now went back and reviewed my "claims" online and it was all there. My insurance was billed directly, so I never saw any billing details.