1. Department of Orthopedic Surgery, Tufts University Medical Center, Boston, Massachusetts, USA.
2. Department of Orthopedic Surgery, Loma Linda Medical Center, Loma Linda, California, USA.
3. Seattle Orthopaedic Center, Seattle, Washington, USA.
4. Department of Orthopedic Surgery, University of Illinois Medical Center, Chicago, Illinois, USA.
5. Department of Orthopedic Surgery, Westchester Medical Center, Valhalla, New York, USA.
6. Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois, USA.