Rennie sorry to hear about your pain. I went thru very similar pain after my TKR ,the pain was below my knee and across the knee cap, as well as the tightness above knee. I tried so many different therapies and drugs with nothing working. I finally received complete pain relief in the knee cap area after a doctor cut my saphenous nerve. This was pretty extreme thing to do but it worked for the knee cap, it had no effect on any other area. But at the point of agreeing to it I could barely work. The pain below my knee , say the top of the tibia , is terrible bu I will keep searching for answers. BEST OF LUCK TO YOU , KEEP MOVING AND SEARCHING . MAYBE THE SAPHENOUS NERVE IS SOMETHING TO LOOK INTO