I Have A Dislocated Knee. What I Mean By That

I have a dislocated knee. What I mean by that is I turned my knee the wrong way mowing and ever since it intermittently has come out of place causing excruciating pain. I have used a knee brace and have experienced swelling on the ankle. Swelled ankle is twice the size as the other one. Even when I take the brace off, the swelling does not go down. Any ideas?