1. Department of Orthopaedic Surgery, Inselspital University of Bern, Freiburgstrasse, 3010 Bern, Switzerland.
2. Shriner’s Hospital for Children, 516 Carew St, Springfield, Massachussetts 01104-2396, USA.
3. Department of Surgery, Orthopaedic Trauma and Lower Extremity Reconstruction, University of Calgary, AC 144E, 1403-29th Street N.W. Calgary, Alberta T2N 2T9, Canada.
4. Rady Children’s Hospital, 3030 Children’s Way, San Diego, California 92123, USA.