It's only 2 months since your TKR and already she's done one MUA and she wants to do another. The lady is really rushing you. When is she going to allow your poor, wounded knee time to heal?I am not very happy about my surgeon and her threats that I could be at a 65 degree bend for the rest the of my life. I am finally starting to feel better in PT with decreased pain, and she has to mess on me. I told her to give me more time to get more ROM and she said we can’t wait.
I'm so sorry she's pushing you. She's wrong and there's no need for it. Your leg won't set and never improve. She's been taught an old myth that should have died long ago - the window of opportunity.
There's no need to rush to get ROM (Range of Motion) because it can continue to improve for a year, or even much longer, after a knee replacement. There isn't any deadline you have to meet:
Myth busting: the "window of opportunity" in TKR
The first MUA did no good and it set back your recovery, because it damaged wounded tissues that are still trying to heal. A second MUA will work no better than the first one did and it will set back your recovery again.
You did the right thing in telling her that you want to wait for more time and see what happens. Stay firm about that. She can't physically force you to have another MUA and she can't do anything without your permission.
You feel as if you're starting to make some progress at PT, so carry on going there, as long as the therapy is gentle and not painful. Discomfort is OK, but pain is not.
Also, make sure that you are spending plenty of time resting, and icing and elevating your knee, to try and reduce swelling. It really only takes a little bit of internal swelling to inhibit ROM.
Go easy on the exercises. It's not exercising that gets you your ROM - it's time. Time to recover, time for swelling and pain to settle, and time to heal. Your ROM is there right from the start, just waiting for all that to happen, so it can show itself.