I tore the meniscus in my left knee last year quite badly. I ended up having arthroscopic surgery because I couldn't straighten my knee (bits of torn jagged meniscus catching on things). It took me about 1.5 months before I could get back on the bike because it takes time for all the muscles, ligamnets etc to heal as well. I was able to walk out of hospital which was good but I had to have physio and do some exercises fr it to heal quickly. I was also only 18 so my age may have been a factor in the speedy recoery. Good luck with your injury. Take it easy and when you get back on the bike, only do it for short amounts of time in a low gear.