Hi Lee,
I'm sorry that your progress seems to be so slow. It must be frustrating for you. We all know and say that patience is your best friend, but patience is so very hard to have!
One thing strikes me from your post: "I am working like a dog to get what feels to me like minimal progress." All the collective wisdom on Bonesmart tells us that
you can't make your knee get better by working it hard. It's wasted effort, so give yourself a break and stop working so hard. At this early stage, your tissues are still healing and too much work will irritate them and make progress slower.
Another thing you say: " PT is painful and I need pain meds after my sessions."
PT should not be painful. If is is, it is either the wrong sort of PT, or you are doing too much at each session. Once again, give yourself a break, and ease off!
Your OS must have a reason for saying that 90 degrees is all you can hope to have for your final flexion. Was your knee very damaged before the operation? If 90 degrees is all that you eventually have, that is sufficient for most things we do, even though more would be nice.
Take comfort from knowing that many of us here have found that ROM continues to improve for a year or more after surgery. It's only a couple of months since your surgery, so you have plenty of time. There's no rush.
Best wishes,
Caryl