[1] Northwest Permanente Med Grp, Dept Orthoped Surg, Portland, OR USA
[2] Kaiser Permanente, Med Device Surveillance & Assessment, San Diego, CA USA
[3] Charles R Drew Univ Med & Sci, Los Angeles, CA USA
[4] Southern Calif Permanente Med Grp, Dept Orthoped Surg, South Bay, CA USA
[5] Southern Calif Permanente Med Grp, Dept Orthoped Surg, Baldwin Pk, CA USA
[6] Northwest Permanente Med Grp, Dept Orthoped Surg, 9900 SE Sunnyside Rd, Clackamas, OR 97015 USA