knee pain

I have another question for you this time about my knee.
I hurt my knee last fall.
If I remember correctly the doctor said I has crushed my Meniscus.
I went thru phyisical therapy but I never got back into gymnastics because my knee has always felts too weak.
I really want to get back into cheerleading but recently I have been getting sharp splitting pain in my knee cap and it has been feeling very weak.
I was wondering if this could be because of my old injury or something new. Also I opted not to have surgery but I had the option.
If I went to a doctor now and he or she felt I needed surgery how long would recovery be if it was for my meniscus?..Thanx again!