1. The Norwegian Cruciate Ligament Register, Bergen, Norway
2. Oslo Sports Trauma Research Center, Oslo, Norway
3. Department of Physical Medicine and Rehabilitation, Oslo University Hospital, Oslo, Norway
4. Surgical Outcomes and Analysis Department, Kaiser Permanente, San Diego, California
5. Department of Orthopaedic Surgery, Southern California Permanente Medical Group, Baldwin Park, California
6. Department of Orthopaedic Surgery, Southern California Permanente Medical Group, Irvine, California
7. Department of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway
8. Faculty of Medicine, University of Oslo, Oslo, Norway