Affiliation: | (1) Hip Service, Schulthess Clinic, Zurich, Switzerland;(2) Rush University Medical Center, 1725 West Harrison Street, Suite 1063, Chicago, IL, USA;(3) Orthopaedic Department, Veneto Regional Hospital, Portogruaro, Italy;(4) Orthopaedic Department, University of Berne, Berne, Switzerland |