Are you sure there is not a fracture in your pelvic area? I too had pain in my buttock that radiated down my leg to my knee. My pain dr ordered a CT scan which showed I had a fracture in my left sacral bone. I too was told by an orthopedic dr that nothing could be done and I have been taking pain meds. My pain dr is going to an epidural in the area to try and give me some relief. Maybe something to check out with your dr.