I had surgery for a meniscus tear and could tell right away that they fixed it when I woke up.
I was not permitted to walk though and after I removed the dressing 24 hours later, my jello blob of a leg ended up freezing into place. I did not like that first PT appt one bit.
However I did go on to do the Disney half-marathon 2.5 months later. So while I didn't walk out of surgery--I was back at it no problem.
OP: I would get the knee checked. Our knee parts aren't supposed to move like that or feel like that. It's a joint we shouldn't notice.