The man's on crutches. And the caption tells the story. Quote, "Cost me [$400] in vet fees and X-rays. Nothing wrong, just sympathy."
So the dog wasn't injured, he was just imitating his owner. The guy and his wife did a TV interview and they even played video of the dog running like crazy when the man wasn't around. This happened last summer, but the video was posted last week.
(Here's theclip.)