Wow! I had no idea that a Baker's Cyst could do that (the things I will hopefully learn in med school). I have one as well - clean knees other than some patellar-femoral pain - my doc has been completely unconcerned about it. I have been doing hip exercises like crazy to try to keep the knee running well - but it honestly hadn't occurred to me it could rupture. It has been annoying me for almost a year. *sigh*
I hope you get some better answers from your doctor, as well as some relief from the pain!
Most days in life don't stand out, But life's about those days that will...