A meniscus tear is generally no big deal. I tore mine running in college. It was mis-diagnosed as ITBS by the crappy campus health center doc and I ran on it for like 3 months. By the time I finally saw a real doctor I could barely walk. I had it scoped, walked out of the hospital the same day and was running basically pain free, with a little stiffness within 2 weeks. Now three years down the road I have put in 70 mile weeks with no signs of trouble. Just get it done. You'll be glad you did.