[1] Trondheim Reg & Univ Hosp, Dept Orthoped, Princesse Kristinas Gate 3, N-7030 Trondheim, Norway
[2] Norwegian Univ Sci & Technol, Fac Med, Trondheim, Norway
[3] Lovisenberg Diaconal Hosp, Dept Orthoped, Oslo, Norway
[4] Haraldsplass Deaconess Hosp, Dept Orthoped, Bergen, Norway
[5] Haraldsplass Deaconess Hosp, Dept Radiol, Bergen, Norway