What Causes Leg From Knee To Toes To Become Cold And Tingly?

I had scope surgery last year on right knee all was fine till the end of Dec. I tipped a snowmobile over and hurt it again, this time around my knee locks up on me then makes a really loud pop when it releases and severe pain when I walk. Now all of a sudden from the top of my knee cap to my toes turns really cold and my feet tingle what would cause this and what should I do