1. Division of Emergency Medicine , Boston Children’s Hospital , Boston , MA , USA
2. Division of Orthopedic Surgery , Boston Children’s Hospital , Boston , MA , USA
3. Departments of Emergency Medicine and Pediatrics , University of Michigan , Ann Arbor , MI , USA
4. Department of Emergency Medicine , Massachusetts General Hospital , Boston , MA , USA
5. Division of General Pediatrics , Boston Children’s Hospital , Boston , MA , USA