1. Department of Orthopedics and Traumatology, Fundacion Garcia Cugat, Hospital Quiron, Barcelona, Spain
2. Department of Orthopedics and Traumatology, Hospital of Viladecans, Viladecans, Spain
3. Department of Orthopedics and Traumatology, Hospital del Mar, Barcelona, Spain
4. Department of Orthopedics and Traumatology, Vall d'Hebron Hospital, Barcelona, Spain