Edema on knee. To get rid of the pain?

While playing football 6 yrs ago I collided with one of the players on the opposite team hardly on my left knee. After that I felt some pain on my knee and went to the doctor. The doctor took some edema out from the knee using a syringe. Afterwards the pain was gone after 2-3 days. Then I started playing normally and there was no issue. Now 2-3 months before while playing I suddenly twisted my knee and the same pain has come back. So is there any permanent solution for it? I mean I didn't twist my knee that much just a little but I felt the pain on my knee. Now that I can't play football like normal. While walking and all its normal but while applying some pressure on that area, I can feel that pain. Even I did an MRI and consulted a doctor nearby. What he said was there was no major issue just a small part of my knee is filled with edema and also suggested me to do physiotherapy. So is there any other way to get rid of the pain?