1. Neuro-Orthopaedic Unit, Orthopaedic Surgery and Traumatology Department, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
2. Departament of Physiotherapy, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Madrid, Spain
3. Department of Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, MO, USA