I would simply ask the OS what is likely to happen if you do not have surgery. If it is a very small tear it might not matter as much. But what can happen if you don't have the torn part repaired or shaved off, is you risk the tear becoming bigger and bigger, which still requires removal and the more meniscus they have to remove, the worse off your knee can be. The menisci sit between your upper and lower leg and cushion the bones so they aren't hitting each other. If you have to have a large section removed, your risk for osteoarthritis goes up because the cushion is missing that protects the cartilage that covers your bones. Also, there is a chance of the tear getting caught in your knee joint and locking your leg and causin further problems or damage. If you can prevent that by having the small tear fixed or removed, you'll be better off in the long run. I would ask for more details on why he is recommending surgery and how large the tear is before you decide. There are tears that can be treated with rest and PT and modification of activities. If you are unsure why he recommended surgery, I'd ask. And if you aren't sure, take your MRI and get a second opinion.