In reply to Marc Langley:
I had surgery to sort out a medial meniscus tear last Wednesday. I live in the Middle East so had it done out here, and was surprised at how well the surgery went and how straightforward everything seemed. With arthroscopy it is quite a minor procedure and from my experience it is the norm to walk out of hospital the same day without crutches. Exactly a week later, I can cycle and walk without any discomfort at all. I don't have full range of movement back yet, but it's improving every day. I'm not doing any resistance training or anything yet, but I envisage being able to do some soon to build the leg back up to full strength.
Before surgery the pain was excruciating and I couldn't bend my leg beyond about 10 degrees as the torn section of the meniscus was stuck between the tibia and fibia. Walking more than about 100 metres was tricky! My understanding is that cartilage has a very poor blood supply and therefore is unlikely to just sort itself out, but I guess that depends how bad the tear is and what complications it's causing. Obviously, removing sections of meniscus can lead to future issues, including arthritis. I'm having to think about running a little less and doing more swimming and cycling, as I've now had surgery on both knees to remove damaged meniscus and don't want to be looking at knee replacements in 10 years....
Whatever you decide, all the best. It sounds like you've got good docs on the case.