I had the same procedure done 10yrs or so ago and seriously lacked in rehab/PT. You will definitely be able to do the squats later but from my experience, you most likely need a bit of a work up to that to get your joint tightened up after the surgery. The decrease in inflammation by starting PB is has helped my knee feel the closest to 100% since before injury. I'd say if you don't squat and keep that range of motion, you'll lose it from scar tissue, and I've had a hell of a time breaking that down.
"You can demonstrate the purpose and limits of human digestion with a simple experiment: eat a steak with some whole corn kernels, and see what comes out the other end. It won’t be the steak."