I also did no PT after my last TKR and I have made a good recovery, with just the normal activities of daily living.
My surgeon doesn't allow any PT at all for the first month after a knee replacement. He says your knee needs that time, to start on its journey of healing. For that month, we rest, ice and elevate our leg, and walk around the house.
After that month, we just go to PT once every 2 weeks, where we are shown a few new exercises to do at home.
His patients all do well and achieve good ROM, as I did, and he hasn't had to do a manipulation to help with ROM for the past 4 years. I think that speaks for itself.
I followed the above regime for the first two knee replacements. I knew what exercises to do, and how much to exercise, so I didn't bother going to PT at all. In fact, I did very few exercises, but just let daily living be my exercise.
Most surgeons are happy to see good results and I don't think they quiz you about what happens at PT. I don't really see any need to raise the subject with them, unless you want a lecture.