Swelling 6 months post ACL OP - No pain at all + full flexion

I hope you can help me with this.

I had a semitendinosus ACL op on 25th of November 2008 in Germany.
So next week it is 6-month post op. I am 31 year-old male. (used to be a professional basketball player till the injury back in October 2008).

I have no pain at all in my knee, and when I finish my daily sports and my body is warm, I can have full flexion of the operated leg (can touch my foot with my back).

However, the swelling (coming from fluid at the knee) has never completely gone after the op.
I went through an intensive physio program, and the therapists used to tell me that it should go in couple of weeks and so on, and now I am almost 6-month post op, and the swelling is still there...

Couple of weeks ago I went back to my surgeon, and he checked my knee intensively, and showed me how stable it is and compared it to the other one. He said that there is nothing wrong rather than me overdoing it with sports. He said that at one point of time the knee will switch off the swelling and it will not come any more.

Now, I have been surfing the internet and I have found negative opinions on having swelling in the knee for a long time after the operation!!!
So I went to another surgeon in a different country, but he confirmed what my original surgeon said!!

My original surgeon prescribed lymph drainage and massage, and the therapists there also told me that there is nothing wrong with me knee.

The problem is:
When I go to train my leg muscles, I feel no pain, and I have no feeling of instability, so I push further and further to end up with a week of intensive 3-hour daily trainings including heavy weight lifting (e.g. 100KG squads), running (5km in 23 min.), jumping drills, lunges with weights, going steps up and down with explosiveness drills ...

After a week of extensive training, my knee will noticeably swell again, but still no pain, after a couple of days of rest, the swelling goes away and I repeat the same routine :) then swelling comes again and so on.

PLEASE let me know, is it normal? some people in the internet think than once swelling is there for more than 2-3 months post op then something wrong may have happened at the operation or during the reha...

However, I did not have any trauma after the op, and I did no rotation movements.

Please let me know your opinion.

Thank you
Regards
Youssef