How do I get this swelling on my knee to go away?

I fell and busted my knee pretty bad about a month ago. Ive gotten it drained 4 times, take anti-inflammatory stuff, ice it, keep it above my heart, I do all that. But its been a month and I still got a squishy sac above my knee. Doctor isnt worried about, I can run without pain, its just there and prevents me from bending my knee all the way? Is there some secret that I dont know of that will make this stupid sac go away for good?