I'm 9 weeks into my recovery from rt. TKR. When I walk I have severe pain in upper posterior thigh. Most of you who have hamstring pain seem to have it closer to knee. I was very knock kneed so I think now that my leg is straight I am using muscles differently than before and causing this problem. My PT has done everything to try and help, but nothing has worked. I don't think it's Piriformis but it might be. Anyone else dealing with this?