1. Division of Orthopaedics and Rehabilitation, Department of Surgery, Southern Illinois University School of Medicine, P.O. Box 19679, Springfield, IL 62794-9679, USA
2. Department of Orthopaedic Surgery & Biomedical Engineering, University of Tennessee, Memphis, TN 38017, USA
3. Clinic for Orthopaedic Surgery, Campus Grosshadern, Ludwig Maximilians University, 80539 Munich, Germany
4. Aesculap AG, Research & Development, 78532 Tuttlingen, Germany
5. Colorado Joint Replacement, Denver, CO 80210, USA
6. Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, CA 94063, USA