Canting angles your boots to binding. Basically one side is raised. Narrowing your stance may help too. Leg exercises also a good idea.
I just did some tweaks on my bindings, since i got a new board, i was riding on a 25inch distance from center to center , so i decided to take it down to 23inch to see how it goes, also changed the highbacks to 2 thei were in neutral, so lets see , i still have the angles on 15/15, so lets see
I had back of knee pain - still have some swelling - but I narrowed my stance, changed my angles and got canted bindings and it is 90% better! Tooke me almost 2 years of changes and riding to get where I'm at today, hopefully it won't take you as long!