This morning my knee have way from under me and I fell, I have been in pain since but it's ok if I don't move my leg, I can walk as long as my leg stays straight, so I know this can wait until the morning as it's not an emergency but I don't want to waste a doctor's appointment (if I get one) if he only send me to A&E.
I have done this before many years ago and was in a splint type thing.