Swelling of r ankle. Total knee replacement may 2012. Infection december 2012. Opened knee again. Now ankle swelling. Cause?

See your doctor. With your history that provided, you need to see your doctor for further evaluation.
Common problem. If a blood clot has been ruled out by testing , your swelling is related to your surgeries and leg infection. These events can cause increased blood flowing into the leg and at time compromise the venous and lymphatic circulation that takes the fluid out. It most cases it is temporary but can last up to a year.