Try to do PT prior to surgery and keep up with it post surgery. Walk, walk walk. I did PT after surgery for 2 months and home exercises. I then had pool therapy and then when I finished that I exercised on my own in the pool. I’m 3 years post surgery and a couple weeks ago I found out my leg extensions is 27 degrees. I have bent knees when I stand straight. I didn’t even notice it because I’m recovering from spinal fusion and have been in extreme pain for over a year. Point is even though I continued to exercise I wasn’t doing the specific knee exercises from PT that work on range of motion and leg extension. It would have prevented this from happening and my therapist thinks it’s permanent now.
Best of luck to you.