1. Department of Orthopedic Surgery, Leiden University Medical Center, Leiden, the Netherlands
2. Department of Orthopedic Surgery, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
3. Department of Pediatric Orthopedics – Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
4. Department of Pediatric Orthopedics, Hospital Universitari i Politècnic La Fe, Valencia, Spain
5. Department of Orthopedic Surgery, Clinica Universidad de Navarra, Pamplona, Spain