[1] Zealand Univ Hosp, Ctr Anaesthesiol Res, Dept Anesthesiol, Koge, Denmark
[2] Copenhagen Univ Hosp, Dept Anaesthesia & Intens Care, Bispebjerg, Denmark
[3] Copenhagen Univ Hosp, Dept Anaesthesia & Intens Care, Frederiksberg, Denmark
[4] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[5] Naestved Slagelse & Ringsted Hosp, Dept Anesthesiol, Naestved, Denmark
[6] Lillebaelt Hosp, Dept Orthoped Surg, Vejle, Denmark
[7] Nordsjaellands Hosp, Dept Anesthesiol, Hillerod, Denmark
[8] Nordsjaellands Hosp, Dept Orthoped Surg, Hillerod, Denmark
[9] Capio Gildhoj Private Hosp, Dept Anesthesiol, Brondby, Denmark
[10] Aalborg Univ Hosp, Dept Orthoped Surg, Farso, Denmark
[11] Naestved Slagelse & Ringsted Hosp, Dept Orthoped Surg, Naestved, Denmark
[12] Gentofte Univ Hosp, Dept Anesthesiol, Gentofte, Denmark
[13] Gentofte Univ Hosp, Dept Orthoped Surg, Gentofte, Denmark
[14] Silkeborg Reg Hosp, Elective Surg Ctr, Dept Orthoped Surg & Anesthesiol, Silkerborg, Denmark
[15] Zealand Univ Hosp, Dept Orthoped Surg, Koge, Denmark
[16] Odense Univ Hosp, Dept Orthoped Surg & Traumatol, Svendborg, Denmark
[17] Copenhagen Univ Hosp, Dept Orthoped Surg & Traumatol, Copenhagen, Denmark
[18] Copenhagen Univ Hosp, Rigshosp, Ctr Clin Intervent Res, Copenhagen Trial Unit, Copenhagen, Denmark
[19] Univ Southern Denmark, Fac Hlth Sci, Dept Reg Hlth Res, Odense, Denmark