1. Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, Oslo, Norway
2. National Knee Ligament Registry, Bergen, Norway
3. Norwegian Arthroplasty Register, Bergen, Norway
4. Department of Orthopaedics, Haukeland University Hospital, Bergen, Norway
5. Department of Surgical Sciences, University of Bergen, Norway
6. Orthopaedic Center, Division of Neuroscience and Musculoskeletal Medicine and Faculty of Medicine, Ullevaal University Hospital, Oslo, Norway