@Jointdoc The new knee is somehow loose, making locking noises when I plant the foot and a less audible noise when I step off. No one can explain whats going on with it. Any ideas?
Hard to say without seeing it - I WILL tell you that all knees can make a little "clicking" with the right movement which is "ok" as long as not painful. Two types of TKA designs - CR and PS. CR maintains the PCL and tends to click less as I think they are a little tighter design. PS knees sacrifice the PS and have a cam and post mechanism and so I think that post tends to "click" in the cam a little more. Essentially metal and plastic clicking.
Sit on the edge of a tall counter or back of truck and let your knee dangle side to side - it will knock/click.
Clicking with walking is a little different - PS knees with rotation off a bit can click. Some people get a patellar "clunk" which is painful - scar tissue that forms underneath knee cap and clunks when it glides over the box of the knee.
Not sure if this helps or not... bottom line - typically don't worry about it unless it hurts - but it can drive some folks nuts.