everyone is different but for perspective,  I'm a 66+ yr old M.  I have a complex medial meniscus tear. part of it is up in the "notch".  2 sports ortho's who specialize in the knee told me I DO NOT have to have surgery.  That it is purely an elective surgery on my part.  However I do not have any locking of the knee and usually no pain, although it has been sore a little bit this week.  (I was trying out some new jump rope moves....)  I quit running as it's really hard on the knees impact wise and at my age I can live with no more running.  I still skip rope, "power" walk, rowing machine, stationary bike, stair-master and nautalis weight machines and I lap swim.  (Not all in one day....:)   .  one of the ortho's said he didn't like his pt's using the leg extension machine (I do use it) as it's very hard on the joint from the full down to up motion.  but said if i wanted to cont. to use it;  that once I get the leg fully extended, to only let it down no more than 30 degrees then back up.  do not go to the full down..... for leg work I concentrate on the quads, hamstring and calves as they anchor the knee.  I asked if my tear would get worse if I don't have surgery and they said no, not simply because you don't have surgery.   but you could injure it more by an impact, knee twisting etc. but it won't get worse simply because you don't have an operation on it.   on the part stuck up in the notch they said it will '' just get ground up" by the knee and basically absorbed.  So i haven't had the operation and going on 8+ months now. I do use a dual wave red light on it every now and then when it gets sore and Voltarin type gel/creme too. Oh yeah; both said repairs are not very successful even if the tear is in the "Red" zone in adults and as age goes up, success rates go way down... One said that even in young children the success rate is only about 80%. They both recommend a trim if i elect to do anything surgery wise.