hi, thank you for providing the brief history of you. A thorough examination of lungs & respiratory system along with musculoskeletal assessment is advised. As, most cases of TKR resumes with good results for almost over a period of 10 years. In some cases due to lack of strength the pain returns and makes the doubt on the TKR procedure or infection. Well, metal do not get infection, so your knee contains metal, and infection is not possible after so long. Also, you can take a physical therapy, by which your muscles can be made to optimum strength and on later stages you will be made to strengthen the core, pelvic floor, breathing exercises for lungs, both legs strengthening, spine strengthening and hip strengthening. As the body functions as a unit, the unit needs a stabilization which can be achieved with the above exercises. I have seen cases post TKR and similar complains. With the assistance of above mentioned exercises they recover well and perform the same exercises at home to avoid future pain. Since body is ageing it needs a continuous exercises for the muscles to keep the body functioning. Regards Jay Indravadan Patel