Post ACL Surgery having effusion in suprapatellar bursa

Hi,

I had ACL ligament Injury while playing Soccer about an year back. I got my knee operated at Hosmat Bangalore about 10 months from Now. I underwent physiotherapy for 2 months and did exercises from then.
After 6 months I started jogging lightly. During all this time I always had pain somewhere at the centre of my knee.
Also I feel a lot of pain while straightening or bending at the extremes. Sometimes it is impossible to walk when I sit for long working hours. I walk with a bend knee most of the time. I am 25 y/o now.
Last week I took MRI again.
Report shows the replaced ligament (patellar tendon) and the screws (Bio-observable), meniscus is fine.
Only problem is "mild joint effusion extending into the suprapatellar bursa".

It would be very helpful, if you can explain this and provide any suggestions.
Yours Response is appreciated.
Thanks & Regards