1. Department of Trauma, Hand, and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
2. Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
3. Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
4. Department of Pediatric Orthopaedic Surgery, Children's Hospital, Hamburg-Altona, Germany
5. Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany