What surgery did you have done to your knees? What was the problem? Did the surgery fix that problem? What problems did the surgery cause?

For patello-femoral syndrome (PFS) see this post:
http://www.bikeforums.net/showthread...1#post16081392

for stretching to relieve various sorts of knee pain, see this post:
http://www.bikeforums.net/showthread...1#post15372967