My therapist in pt had me doing lunges and squats on a trx machine because I have weak glutes. It turns out that was the cause of my back and periformus issues from the first knee. After I finished pt this time, I started doing sessions with a trainer at the gym who is a former pt assistant and and understands the issues. He has me doing them with assistance and not many reps. At what stage has anyone else done lunges and squats? I admit they do bother my knees, but the glutes and back are better. It's a catch 22.