Selected Instructional Course Lectures THE AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS * FRANKLIN H. SIM, Editor, Vol. 50 COMMITTEE JAMES H. BEATY, Chairman FRANKLIN H. SIM S. TERRY CANALE DONALD C. FERLIC DAVID L. HELFET EX OFFICIO FRANKLIN H. SIM, Editor, Vol. 50 DEMPSEY S. SPRINGFIELD, Deputy Editor of The Journal of Bone and Joint Surgery for Instructional Course Lectures JAMES D. HECKMAN, Editor-in-Chief, The Journal of Bone and Joint Surgery *Printed with permission of the American Academy of Orthopaedic Surgeons. This article, as well as other lectures presented at the Academy’s Annual Meeting, will be available in March 2001 in Instructional Course Lectures, Volume 50. The complete volume can be ordered online at www.aaos.org, or by calling 800-626-6726 (8 A.M.-5 P.M., Central time).