1. Carilion Clinic Orthopaedics, Viginia Tech, Roanoke, VA, USA
2. Rothman Institute, Thomas Jefferson University, Philadelphia, PA, USA
3. Technische Universität München, München, Germany
4. Department of Surgery, University of Miami, Miami, FL, USA
5. Independent Statistical Support, Rochester, NY, USA
6. Department of Orthopaedics and Rehabilitation, University of Texas, Houston, TX, USA
7. Department of Orthopaedics, Veterans Affairs Hospital, St. Petersburg, FL, USA