I am about 4 months PO and have a pain like a tendon or ligament pulling and then snapping back of my knee. It started about 6-7 weeks, happens every time I go from sitting to standing, and starts about 10-15 minutes when I walk. Is this anything like you have? My OS doesn't seem concerned either, but by the end of the day it really is hurting. It seems like I traded one pain for another. I have really been working on strength exercises thinking maybe if I build my muscles up more it will stop. When I suggested to my OS that I see a different kind of doctor for it, he out and out told me no one's touches my knee except him. I politely as possible told him if it still hurts like it does at my 6 month checkup either he addresses it or I will be seeing another doctor. He believes by 6 months I shouldn't be having this problem. We shall is.