Until TKR becomes an exact science you should never feel blame in the world of "let's see if it works" surgeries. My experience in the past seven years of physical therapy with many different therapist is that they have different methods of treatment. It seemed like whatever my exercise routine was my new therapist made changes. I would either be doing not enough or doing too much, always looking for that magical sweet spot.
My first surgery, seven years ago, was a disaster where I did all the PT that was assigned. On my second surgery on my other knee I decided to do nothing more than PT at the PT location. This is now my good knee. This decision was based on the disappointing outcome of the first knee. When I tell this story to my Ortho I never get feedback.