My Daughter's Bike Breaks Off

My daughter, who will call alex, was riding in the street in front of the house with her cousin. All of a sudden i heard some screaming and crying out. And alex was sitting in the street holding her leg. Half way down on the inside of her left leg, the skin was split to the bone. I picked it up and noticed the part connecting the pedal to the crank arm as sheered off,. leaving behind sharp little points. The other half was still in the crank and had left the same sharp pieces.