Hey Ken,
I had the same experience about 5 days after my surgery. My wife (who is a nurse) kind of freaked out about the bruising and swelling down by the knee. She grabbed her keys and was ready to haul me to the ER. I calmed her down a bit and explained that that is normal acocording to the post surgery flyer the Dr's office gave me , as well as verified this from my surgeon. She and I did however question the TED stocking, although in general they are very necessary for prevention of DVT's as prescribed by my surgeon. They tended to roll down to just under the knee due to me having big thighs. Where these rolled down there was a "normal" color to right around where the stockings rolled down and the bruise appeared worse above it where the stockings were restricting circulation around the bottom of my knee. I went on the TED site and they have instructions to use these properly. The bruise did however go away extremely quicker than I expected. I'm with oldsoccerplayer, elevation and icing was key!!
Im 6 weeks out now and still ice every night, even though I don't see any swelling!