It is an extremely common knee injury.  It can be the only injury or also go along with much more significant injuries such as an ACL tear.  My wife has had her's repaired/trimmed in the past and due to a degenerative issue she will need a knee replacement in the future but she is putting it off as long as possible. She not longer runs but still walks and rides a lot of bicycle. (She's part of the group that some AgTalkers despise because she uses a road for something other than driving).  Many people will have meniscus repaired and resume a normal lifestyle.  It is totally dependent on the severity of the injury.  I was diagnosed with a minor detached meniscus 10 years ago.  Other than some stiffness when I bend it too much it doesn't cause me issues.