CHICAGO, ILLINOIS.*One or more of the authors has received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article. In addition, benefits have been or will be directed to a research fund or foundation, educational institution, or other non-profit organization with which one or more of the authors is associated. Funds were received in total or partial support of the research or clinical study presented in this article. The funding sources were National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases Grant AR 39310; Zimmer, Incorporated, Warsaw, Indiana; and a DePuy Career Award from the Orthopedic Research and Education Foundation (J.J.J.).(JACOBS, URBAN) Department of Orthopedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, Rush Medical College, 1725 West Harrison Street, Suite 1063, Chicago, Illinois 60612. E-mail address for Dr. Jacobs: email@example.com.(GILBERT) Division of Biological Materials, Northwestern University, 311 East Chicago Avenue, Chicago, Illinois 60611.