Institution: | 1.Department of Orthopedics,University Hospital,Eyrarlandsvegi,Iceland;2.Department of Orthopedics,Clinical Sciences Lund, Lund University,Lund,Sweden;3.Department of Health Sciences,University of Akureyri,Nordurslod 2,Iceland;4.Faculty of Medicine,University of Iceland,Reykjavík,Iceland;5.Clinical Epidemiology Research & Training Unit,Boston University School of Medicine,Boston,USA |