Just relax the leg, grasp the patella like your gently picking up a ball off a table with your fingertips, and move it around circular and side to side, up and down for 5 minutes. My PT guy said he did that to work on adhesions. This was done at the start of every PT session. He pinches up the skin on the top of the patella also, I guess to make sure nothing adheres there. .
My progress is pretty slow now. Just more ability to walk without a gimp. Getting better with stairs but still use bannister/hand rail while bending the repaired leg to hold while stepping down stairs. Not so much with the bannister when using the repaired leg to lift going up the stairs. Not real fluid movement, but getting better. Slopes are a bit of a challenge going down. Usually traverse sort of sidewise, back and forth.
Week 17 post surgery will be Wed.
Looks like you are a little bit ahead of where I am with descending stair steps, but any day now, just you watch, I'm going to positively start getting in some good reps stepping off my paperbacks! (coming for you)