1. Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 300, Chicago, IL, USA
2. Department of Orthopaedic Surgery, Shriner's Hospital for Children, Sacramento, CA, USA
3. Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
4. Department of Orthopaedic Surgery, University of Rochester Medical Center, Rochester, NY, USA