My Right Ankle Has Started Swelling Every Since I Had

My right ankle has started swelling every since I had my 4th lower back surge. The doctor fused,put rods and screws in my back. It seems that if I do alot of bending and if I set in a chair or on the couch it starts swelling. I have asked doctors about why it swells and when I lay down at night most of the time it goes down. My husband doesn't believe that it has anything to do with my back and he thinks that I'm going to have a massage hart attach. Please help!