Can i sue my doctor if he told me i didn't have a meniscus tear.?

I had a patellar repair and chondramalcia debridment its been 6 months and plenty of therapy, At the present i still cant alk up stairs properly, cant sit or stand for long length of tim,.Now im about to lose my job of 15yrs+ because of my restrictions.Thee job offered me to apply for ada. Took the papers to him, first of all he write all these restrictions as mention above and on the last page it ask if t affects me walking and he said no,then he write my diagnosis is os and torn meniscus in both left and right knee. PLEASE HELP