[1] Univ Oxford, Inst Musculoskeletal Sci, Oxford, England
[2] Univ Southampton, MRC Epidemiol Resource Ctr, Southampton, Hants, England
[3] Royal Natl Orthopaed Hosp, Stanmore HA7 4LP, Middx, England
[4] Medtronic Ltd, Watford, England
[5] Karolinska Inst, Med Management Ctr, Stockholm, Sweden
[6] i3 Innovus, Stockholm, Sweden