1. Carnegie Mellon University, 403 Landon Gate, Pittsburgh, Pennsylvania 15238, USA.
2. Jefferson Regional Medical Center, 575 Coal Valley Road, Pittsburgh, Pennsylvania 15236, USA.
3. UPMC St. Margaret’s Hospital, 815 Freeport Road, Pittsburgh, Pennsylvania 15215, USA.
4. Department of Orthopaedic Surgery University of Pittsburgh, 3471 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA.
5. Department of Orthopaedic Surgery Stanford University, 300 Pasteur Drive, Palo Alto, California 94305, USA.