I am 7 weeks post LTKR and have kneecap pain as well. I've had it off and on since the beginning. What I think I'm beginning to figure out with myself is that when my knee area swells, I feel it mostly in my kneecap. I also have been doing some light yoga for the past couple of weeks and wondered if down dog might be too much of a stretch for my tight hamstrings. That said, how is your extension? I find I can get my knee to extend to 0 earlier in the day after I do my exercises, but as the day wears on and my knee swells, my extension gets worse. It's like it has a memory from my pre tkr days! The reason I mention it is that one afternoon my pt noticed I was not fully extending my leg when I walked. She said the pressure of continuing to walk with a slightly bent knee may have been making my knee cap pain worse. Now I am deliberate about working on the extension when I walk. It is not perfect, but I can say I don't have as much pain when I am careful and mindful of my steps. As everyone on this forum tells me, it is a process and the extension will come in time.I hope this helps