Well...
In MRI, you have two types of ligament of the atomic orbits, of hydrogen containing material inside of your body....The first aligns the orbits of the atoms, parallel to the magnetic powerful field (2-3- Tesla units) THAT is T1, where you can see water as a dark substance.
Then you have the alignment of the orbits perpendicular to the magnetic field, so that you can detect other type of lesions, because water is seen in a white color. This is your T2.
T2 signals can mean anything... From absolutely squat to multiple sclerosis to bleeding. I sincerely doubt it's any of those since you're saying this was a while back and you aren't complaining about dying or excruciating pain. Being that posterior horn of the medial meniscus is referring to your knee ( assuming you've relayed this correctly ) I think you'll live... which is the good news. The other good news is that this injury is incredibly common and you really don't have anything to worry about most of the time. There's really nothing to be done. 90% of people put under an MRI would have this same result come back. Cartilage breaks down and things don't work as well as they used to, it happens.
Lastly, no doctor, P.A., surgeon or any medical staff can make any sort of diagnosis off of such little information. Being that I can not see the MRI results in front of me or the scans, I am left to tell you that you're not dying and that's about all I can give you. Giving me that much information is like telling a mechanic that you need a bolt remover thingy for the thingy under the hood of your car located next to the other thingy that spins. Seriously, that's what that amount of information tells anyone. You're not dying, that's what I can definitely tell you... congratulations.