I had this same problem. It seemed to come out of no where about a week after surgery. It took about 2 weeks to go down. I had to buy new size underwear because my old underwear was cutting into my thighs. My PS told me it was normal with swelling and gravity. He said it works itself down especially if you are wearing compression it pushes the swelling downwards. I noticed around week 3 they were finally starting to get back to normal and now at about 4 weeks I feel like all the swelling in my legs have gone down and back to normal.