I had athroscopic knee surgery, acl recons. and meniscus 5days ago. ankle is now swollen and bruised, i believe hematoma. it is very painful. danger?

Not generally: It is hard to say that there is no danger here. Bruising and swelling around the ankle is possible after acl reconstruction, but is not the norm. It definitely reflects bleeding from somewhere. The acl tunnel in the front of the leg can be a source of bleeding. Bleeding that starts in the back of the knee is much less typical and warrants a visit to your surgeon, especially with the "very painful".

I had arthroscopic k: Call your orthopedist asap, you might have infection for which you need an antibiotic and most importantly you might have a blood clot in the leg, you need venous ultrasound to r/o that out. Both conditions should be treated right away.

Hematoma: Following acl surgery especially if your own (autologous) bone patellar tendon bone graft is taken swelling, bruising in the ankle is not uncommon. Just make sure that you are not having any sharp calf pain where a doppler ultrasound would be helpful to be performed to rule out a blood clot.