My experience was like @babyjay5977 's. I've had a clicking sensation, which is much like a light cracking of knuckles, but there has never been any pain with it. More of just feeling it, not sure anyone else can hear it. I don't notice it unless I purposely think about it. I have it in both TKR knees, a bit more in my first surgery right knee. It's been over 5 years for the surgery, and has not caused any problems. I have wondered if I worked more at building up the muscles around the knees, they might somehow provide more "fill" and stop any shifting that might be causing the clicks. But there needs to be wiggle space in the knee cap for the shift in arc as you flex and bend your knee, so I'm guessing this might be one of the trickier bits to get perfect in surgery.