I slept with the knee brace locked for 8 to 9 weeks... (not everyone keeps it on that long). You'll likely have numbness for many weeks / months / first year. You just had major surgery, so don't think the pain / numbness will go away anytime soon. Use a knee pillow when sleeping on your side.. (I still use a knee pillow, years later on occasion).
If you are not already in physical therapy, you need to be in physical therapy NOW, I was in PT like 2 days later after surgery. Don't wait... or else you will be worse off the rest of you life.
Read through this article I wrote and all the comments to get a better understanding of everything: