1. Department of Orthopaedic Surgery, Kaiser Permanente South Bay Medical Center, Southern California Permanente Medical Group, Harbor City, California
2. Medical Device Surveillance and Assessment, Kaiser Permanente, San Diego, California
3. Department of Orthopaedic Surgery, Kaiser Permanente Los Angeles Medical Center, Southern California Permanente Medical Group, Los Angeles, California
4. Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington
5. Department of Orthopaedic Surgery, Kaiser Permanente Santa Rosa Medical Center, The Permanente Medical Group, Santa Rosa, California