I accidently smashed my knee into a metal blockade-type post at work two days ago.?

It was already injured by being dislocated about 35 years ago. And recently I have been feeling some arthritis pain from it. Since I accidently smashed it the other day, it has a black and blue mark on it and it is swollen. What is good to take for it? I took ibuprofen. Should I be taking something else for it? What is the best way to take care of it? I am able to walk with it, in spite of the swelling. Is it better to keep my leg up or is it alright to walk with it?