Hi Dani
Sorry to hear you are having problems with your knees. I think you should go and see your Doctor, I am he wont recommend surgery without checking out others ways to fix your knees, he may just refer you to a physiotherapist, to see if your problem cant be sorted that way.
It's really best to get it checked out, as you could be doing more damage than good by just leaving it.
I Hope this helps and take care.
Hugs Dee x