"Threats" and scare tactics are not very productive ways for doctors to "help" people. :( My OS was quite pleased when I made it to 90 at 6 weeks. Not coincidentally that was the point at which my swelling had decreased considerably. I did heel slides and so forth and it wasn't comfortable, but I didn't let any PT "crank" on my leg, nor did they try to. My approach was to use my common sense-- take the knee through its range a few times a day (to discomfort but not agony) and do a lot of icing and elevating. In my experience it's a daily balancing act. Use the knee but don't aggravate it. As I continued to heal over the months I would do more daily activities that required me to bend my knee and I continued to see progress. (My OS was ok with that approach, by the way).