@saeternes, my doctor prescribed that I use 20 - 30 mg compression stockings to help with the swelling in my legs from lymphededema. The first time I bought them at the Mayo Store at about $80 a pair. Since then I've been ones that work just as well for me and they are a lot cheaper if I buy them online. This past year I've purchased several pair of side zippered compression socks and they are so much easier for an old guy to put on. My plan is to keep buying these as my old ones wear out. They are pretty thin so in the winter time I generally wear some other socks over them.
https://www.amazon.com/gp/product/B07LDCXZZH/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Hope you read the remainder of my comments, that MOST people do not have the problems with leg extensions. I did not mean to scare you off, just pointing out that a pillow crosswise under the knee is a bad idea. However, I found that once in a while an extra long pillow lengthwise under the TKR leg provides some nice and comforting cushioning (or perhaps even a body pillow).