The pads may also act as mental reassurance.
Beagle, I too snapped off a large lump of knee cap, lost 25% of the suface area and part of the track, the surgeon had great pleasure showing me the one pound coin size lump of bone and cartlidge. Again like you my injury was done walking, on a fell in the lake district. When you did your original injury didn’t have problems with falling over for no reason? Likely when this happens I always land on the other knee.
Got one last session with physio in two weeks time, so i’ll ask his advice