If it is really a torn meniscus, there are there are sort of three possiblities:
1. The tear is not bad enough for surgery. I did this years ago and sometimes it aches, but not bad enough to go under the knife. If it gets too achy injections might help (but not heal) the problem.
2. The tear is sufficiently large that the loose ends get crunched during knee movement and the pain is pretty sharp. This is fixed with simple surgery that just cuts off the loose parts (probably what Outback_Jon's wife had). I had this surgery a little over a year ago and everything went well (in fact they wouldn't even let me leave the hospital unless I could walk out). I was back at my job as a preschool teacher in a week. This sounds like what you've got.
3. The tear is deep or goes all the way through. This is a much bigger deal in terms of the complexity of the surgery and length of recovery.
Finally, there are a bunch of parts/pieces/connections in a knee and the problem could be something entirely different -- and this is why you want to see a surgeon ASAP.