How Can Acute Leg Edema Be Treated?

I have edema in both of my legs. 13 years ago I broke my left foot. Before then I had minimal swelling. Afterwards my left leg swells more than my right. I have had a US which showed 2 perforators that were incompetent. I am an MRI tech and we were testing our new scanner today. They scanned my left leg and it is full of fluid in the whole lower leg. They were also able to see some on the right side. Is it possible that the fluid could be coming from irritation in my knee joints. I need knee replacement surgery on both sides. There has been fluid in both joints. I do have an appointment with my ortho tomorrow.