Warning: the video is *very* graphic. So if you're easily queasy, don't watch it.
This is the effect of krokodil, a street drug that is a problem in Russia.
Krokodil has become notorious for producing severe tissue damage, phlebitis and gangrene, sometimes requiring limb amputation in long-term users. (http://en.wikipedia.org/wiki/Desomorphine#Effects)
The drug literally kills off your limbs and skin while you are still alive, and they begin to rot. It does the same to organs, as well, if used long enough.
I'm just going to give the URL because the thumbnail of the video already shows graphic stuff.
After www.youtube.com add /watch?v=REP6NCDfAtg
P.S. While of course I can't understand what's being said, my Russian friend said the guy having his legs worked on is pretty calm through the whole thing... "yeah, looks good, looks good," stuff like that. He's just amazingly detached from what has happened to him.