HI,
I noticed that we can start to develope patterns when we ride, that feel normal but may not be in the best interest for our knee's.
I also had problems with my left heel striking the frame, I went to mtb pedals to much drift and the pedal surface felt to narrow and my foot rocked around a little, and after a few months finally went to keo style pedals with red cleats and after another few months tried the black or locked cleats, when I installed the cleats on my shoes I adjusted the cleat to point my toes in a little this pulled my knee's in and at first it felt off, but after a while it seemed more normal.This also required a minor seat adjustement due to the extra lenght My legs had to grow muscles in new spots after the change in ridding style.any adjustment will require time to be sure its right and not new..
Its amazing how quickly we can adjust to bad ridding habits and not realize they can be bad mechanics.
I also found out I have leg lenght problems that tend to favor my right leg. SO I put pads under my cleats that force my foot to the outside of the pedal and lean a little to the outside of the pedal this felt off at first but soon became normal after a few rides and may prevent further problems this improved the tracking of the patella over the knee preventing pain..
Doug
each person has unique bones and body parts from torso lenght to arm/leg. so fit is key..
here's some neat stuff for your bicycle shoes and cleats
http://www.bikefit.com/products.php