I always whack my shin when I try to put my pedal in its lowest position to push off on as I swing my leg over the saddle to take off. It seems I miss the pedal on the way around and it keeps going until it hits my shin. Metal platforms are the worst. I had my foot slip off a pedal once when I stopped too fast, and it went into the screw on the side of my fenders. I ruined my sock with blood and I still have a divet like scar 5 years later.
About the knee, I would take it easy--ie
nly ride on flat ground where you can control the pressure you put on it. I think a doc would say use ice and ibuprofen. Keeping it moving is probably good for it.