1. Department of Orthopaedic Surgery, Westchester Medical Center, Valhalla, New York, USA.
2. Department of Orthopaedic Surgery, Lenox Hill Hospital, New York, New York, USA.
3. Department of Orthopaedic Surgery, Wake Forest University Medical Center, Winston-Salem, North Carolina, USA.
4. Veterans Administration Loma Linda, Loma Linda, California, USA.
5. University Hospitals Geauga Medical Center, Cleveland, Ohio, USA.
6. Department of Orthopaedic Surgery, The Rothman Institute, New York, New York, USA.
7. Department of Orthopaedic Surgery, Loma Linda University Medical Center, Loma Linda, California, USA.