I am experiencing the same problem. Had a left TKR on February 2nd. Started PT two weeks later and was pushed pretty hard to bend my knee. If I try to replicate the exercise I now hear a snap or pop and then it goes back into place. I had to stop PT due to Surgeon's orders. He wants to see if my inflammation goes down. It now occasionally is happening without any exercise that requires bending. I am waiting to go back on March 20th and have been forbidden to do PT until he sees me again. How did you get rid of this problem. I am worried I will need arthroscopic surgery to remove the tendon as he alluded to something along those lines.