New York, N.Y.Investigation performed at the Department of Orthopaedic Surgery, Hospital for Joint Diseases, New York City.*Although none of the authors have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article, benefits have been or will be received but are directed solely to a research fund, foundation, educational institution, or other non-profit organization with which one or more of the authors are associated. No funds were received in support of this study.**1095 Park Avenue, New York, N.Y. 10128.***Hospital for Joint Diseases Orthopaedic Institute, New York University Medical Center, 301 East 17th Street, New York, N.Y. 10003.