So, today is my one week post-op. Today was slightly better but still having a LOT of intermittent pain. Getting up and stretching some and trying to ever so slightly bend my knee and then attempt to straighten again. I talked to my surgeon yesterday and he said he’s concerned with me not bending my knee at all that I could develop scar tissue and have a permanently stiff knee. :( They upped my pain meds dosage because the pain was so out of control and as a result, I was extremely nauseous yesterday, despite Zofran. So I’m back on 10 mg of Oxycodone every 4 hours and 7.5 mg of Mobic twice a day, along with Tylenol 3x a day. He said it’s mind over matter; said I have to push through the pain and try to move it. I thought compared to my knee osteotomy and cartilage restoration, knee replacement surgery was supposed to be a piece of cake. This is brutal.
I heard the same scar tissue concern from my surgeon. I think that this is pretty common guidance. While I think it is a good idea to bend it at least a little bit, but you don't need to be hyper-aggressive about it. Figure out the difference between discomfort and pain. When you're doing your heel slides, or for that matter any other exercise, find your maximum discomfort and don't push past that. I liken it to how intense a really good stretch feels when you're cooling down after a workout. Some people "enjoy" the stretch but I never have - it is an intense feeling and now I know that for me, it is discomfort. That's the kind of feeling you're looking for in your ROM exercises. If you go beyond that into pain, you're doing too much. And this early in your recovery, you may be surprised by just how little you have to do, to be doing too much! I know I was, and I am only one week ahead of you.
On the drugs front. Like you, the Oxy made me nauseous. Zofran helped a little but what was the ultimate help was never ever taking the Oxy without a reasonable amount of food. The least amount I would take with it would be an apple and a package of almonds (about 100 calories worth). This made a big, big difference in my level of nausea.
Good luck. It is hard but you will get through it.