[1] Univ Oslo, Inst Hlth & Soc, Dept Hlth Management & Hlth Econ, Fac Med, Oslo, Norway
[2] Univ Oslo, Akershus Univ Hosp, Dept Orthoped Surg, Oslo, Norway
[3] Univ Oslo, Inst Hlth & Soc, Dept Gen Practice, Fac Med, Oslo, Norway
[4] Oslo & Akershus Univ Coll Appl Sci, Fac Hlth Sci, Dept Nursing, Oslo, Norway
[5] Univ Oslo, Inst Clin Med, Fac Med, Oslo, Norway
[6] Oslo Univ Hosp, Intervent Ctr, Oslo, Norway