Look into Iliotibial Syndrome. I had excruciating pain for 9 years after TKR. Praise God, an informed PA suggested it could be IT syndrome. The surgeon had only given me the option of opening up the knee and "taking a look" years earlier when I sought help. I did an internet search and started doing exercises and stretching unlike any I had done before. I got some relief in a couple of days and now am doing PT for it specifically. Previously I tried PT twice, stretching, strengthening, acupuncture, cold laser, topical cream, opiates. Primary told me I was just going to learn to live with it. IT syndrome can be caused by TKR but it is rare.