1. University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
2. Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, Michigan, USA.
3. The University of Edinburgh, Edinburgh, UK.
4. University of California, Los Angeles, California, USA.
5. Steadman Philippon Research Institute, Vail, Colorado, USA.
6. Author deceased.
7. American Orthopaedic Society for Sports Medicine, Rosemont, Illinois, USA.