How To Cure A Possible Collateral Ligament Damage ?

I had injury while training karate; I kicked with my right leg and when I landed, something happend. I don t know what exactly, but slowly (in about month or two), everything was getting better, but not 100%, so I went to doctor. They said that there might be collateral ligament damaged, but they just said I should work out for my thigh muscles....But then once again (first time was december 2010, and then second time march 2011) the same thing happend (as if my knee went out of it s position and jupmed back). I went to doctor immediatley and I got crutch for one week and once again they said that cruciate ligaments look fine and that there might be latteral ligament streteched and that my kneepan moved too much -left and right; but there shouldn t be a problem if I strengthened my thigh muscle. But now after a half jear I want back to get note for MR (to be sure everything is OK), and the same doctor said I had crushed cruciate ligament (one of them, don t know which exactly), and that my kneepan really moves too much (the first time he said Arothmetere on left was -3+13 and on right -3+12) but now it was the same on left, and -3+18 on right (the injured one). He mentioned operation, but first of all I have to go to MR and then I ll see. Now my question is, can I got to fitness and work out for my thigh muscles or should I rather not? Because I didn t went to MR the first time, I don t know for sure if there was something wrong with crucial ligaments the first time, and now is-so did doctor not notice that the first time, or did that happen while training again after injury (nothing similar happend after the second injury). I probably shouldn t train now until I get MR results, but can I got to fitness and train my muscles so at least something will be done? I don t have any pain, but I can t contract my leg fully (if I can contract my left leg 100%, I can do with right 90%), and it s a bit strange when I try to contract it fully, as if something jumped left and right(or in and out)...And I can feel some bone on the upper right side of the knee that jumpes a bit when I extend or contract my leg (it s the same on the left, but if I want to notice that on the left I have to press my finger on it...on the right it s more obvious). And the second, should I visit some other doctor to see different opinion? Thanks for your ancer in advance!