Had total knee replacement 6 mon ago now i can hear it flap or knock when i move my knee from right to left and it flaps when i walk still hurts ?

Be checked: It may be an issue with the patellafemoral joint. I would encourage you to let your surgeon know.

Clicking and TKR: Most knees click and knock. After knee replacement. Painful clicking, knocking and or flapping should be checked out.

Metal on plastic: The knee replacement is made of metal and plastic. As hard surfaces, when the knee joint moves against itself, the hard on hard surfaces can make a click or clunk sound. Not usually a sign of failure, simply the implants hitting against itself. Associated pain should be evaluated, however. Typically, the knee gets stronger for a year after surgery, which can help tighten and strengthen the knee