1. Department of Orthopaedics, University of New Mexico, Albuquerque, NM, USA
2. Kaiser Permanente, Freemont, CA, USA
3. Shiley Center for Orthopaedic Research & Education at Scripps Clinic, La Jolla, CA, USA
4. Division of Orthopaedics, Scripps Clinic, La Jolla, CA, USA