I too have had my femurs derotated. I didn't do both legs at once, I did the right and then about 6 months later did the left. I started with the surgeries when I was 18 or 19... I have had pain in my knees and hips all my life, and had always complained. The doctor always told me it was just growing pains and it would go away. Well, it never did and so I had the surgery to derotate my femurs. Part of me wishes I would have had it done when I was younger, then maybe I would have less pain now... years of being twisted couldn't have been good. I don't regret having the surgery, my legs are much more stable now. I don't worry about tripping or falling. I can run if I have too, whereas before I couldn't. The recovery was long, but not terrible... I had an epidural and after that the pain was manageable with meds. I can't imagine having both legs done at once, but I they do that with the younger patients sometimes. Although, my first surgery went really well, so I wasn't hesitant to do the left leg. Of course the left couldn't be as easy, no it still causes me pain sometimes.
Hope all goes well for you guys!