I went to see the surgeon that operated on my knee after i had surgery and a new mri and it showed a displacement of meniscus root but doctor said no?

Discrepancy: Sometimes surgeons and radiologists lack consistency with their diagnoses. Surgeons have the luxury of evaluating patients clinically. The surgeon may agree with the picture the radiologist is looking at, but your chief complaint may not match your physical exam findings. That is potentially why you see a discrepancy between the two disciplines.