How To Reduce Knee Stiffness After Having A Knee Surgery?

Hi, I had a road accident in 2003 and I had a knee surgery and since then I have stiff knee. I can't bend it and I really have a problem I just didn't complete my exercises what my doctor gave me then now I can't fine the way how to do it.. Is there any surgery or anything what can bend my 7 years stiff knee.