What are the causes of swollen ankles after foot surgery?

Surgery itself: If both of your ankles are swollen, then it could be due to the amount of IV fluids . If it is on the same foot that you have had the surgery, then it is normal. If any bone procedure was done to correct any deformity, you can think about it as being the same as if you broke a bone in your foot. Your foot and ankle will swell. With time is should go away. Let the surgeon know, elevate and ice.

Tight bandage,: Also part of the normal healing process is to have inflammation particularly after tissue was cut into. The important thing is to make sure the swelling is not accompanied by redness which may be indicative of infection.

Swelling: It would unusual to have swelling in both ankles just from surgery on one ankle. You don't state when the surgery took place. If you have any concerns at all speak to your surgeon.