[1] Oslo Univ Hosp, Div Orthopaed Surg, POB 4956 Nydalen, N-0424 Oslo, Norway
[2] Univ Oslo, Inst Clin Med, Fac Med, POB 1078 Blindern, NO-0316 Oslo, Norway
[3] Norwegian Sch Sport Sci, Oslo Sports Trauma Res Ctr, Dept Sports Med, POB 4014 Ulleval Stad, NO-0806 Oslo, Norway
[4] Oslo Univ Hosp, Dept Clin Serv, Div Med, Sect Physiotherapy, Oslo, Norway
[5] OsloMet Oslo Metropo litan Univ, Fac Hlth Sci, Dept Rehabil Sci & Hlth Technol, Oslo, Norway
[6] Akershus Univ Hosp, Norwegian Inst Publ Hlth, Hlth Serv Res Ctr, Oslo, Norway
[7] Univ Hosp Schleswig Holstein, Inst Emergency Med, Holzkoppelweg 8-12, Kiel, Germany
[8] Univ Oslo, Inst Hlth & Soc, Dept Gen Practice, POB 1130 Blindern, NO-0318 Oslo, Norway
[9] Oslo Univ Hosp, Ulleval Hosp, Div Prehosp Serv, Cecilie Benedicte Isern, POB 4956 Nydalen, NO-0424 Oslo, Norway