1. University Children’s Hospital, Department of Pediatric Orthopedic Surgery and Traumatology, Medical University of Bialystok, Waszyngtona 17, 15-274 Bialystok, Poland
2. Paley European Institute, Al. Rzeczypospolitej 1, 02-972 Warsaw, Poland
3. Department of Orthopedics and Traumatology, Helsinki University Hospital, 00260 Helsinki, Finland
4. Department of Orthopedic Surgery, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110, USA
5. Department of Orthopaedic Surgery, Nemours Alfred I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803, USA