Its more likely that the bear was caught in a wolf or lynx snare. A bear snare would most times cinch down just above the foot, although infection could have caused the area above the snare to become necrotic and fall off. Having watched bears moving on their hind legs more than several dozen times, this bear is remarkably fluid in its walking motion. The typical bear gait when using only its hind legs is an awkward, plodding motion. This bear's skill could potentially come from practicing, although there are likely muscular and skeletal contraints to a bear walking so fluidly. Who knows except for the videographer? It won't surprise me at all to discover it is a hoax. It would not shock me to find out its true, either.