mine do this to, for me its because of excess elastin in my body- i cant see how this effects them though. my dr was suprised iv never dislocated my knees before, they also bend backwards, a great party trick!
this doesnt look too hopefully for me...i dont have pain when they click...but the rest of the time i've got pain in one knee, mum thinks it could be tendonitus...hmm..mebbe i should give the doc a ring...