1. Department of Orthopaedic Surgery, Diakonessenhuis Utrecht, Zeist The Netherlands
2. Department of paramedical treatment and rehabilitation, St. Antonius Hospital, Nieuwegein The Netherlands
3. Department of Pediatrics, St. Antonius Hospital, Nieuwegein The Netherlands
4. Department of Orthopaedic Surgery, Wilhelmina Children’s Hospital-University Medical Centre Utrecht, Utrecht The Netherlands