I’ll be devil’s advocate here and give PT its props. A really wonderful therapist rehabilitated my frozen shoulder a while back using only exercises. I went from very little function (couldn’t reach above my chest, out to the side, or behind my back at all) to having full function of my left shoulder. True, she told me what exercises to do, and I did them, but she knew her stuff. She told me what she was doing and why. I respect that.
The difference I see is my shoulder was intact. Dysfunctional, but not operated on. There was no soft tissue damage trying to heal itself while I built up this muscle group, then that muscle group, restoring balance to get that part of my musculoskeletal system working properly again. I have a hard time understanding why physical therapists would think they can rehab a freshly operated, desperately trying to heal knee the same way they would weakness or stiffness in a non-injured leg.