My situation is similar to yours in some ways but different in other ways. I’m three years post TKR and still have several issues including soft tissue pain, scar tissue, and stiffness that limits my mobility. I’ve have every test, including a scintigraphy that showed that my implant is not inflected or loosened. However, I am most comfortable in bed or with my leg raised. Like you, I have only one kidney (born that way) so cannot take anti-inflammatory meds. I have just started soft tissue massage at a sport medicine center that I’m hoping will bring some relief.