Total joint arthroplasty has brought manifold benefits to patients suffering from joint diseases, but the durability of prostheses remain a persistent problem, often requiring correction through revision surgery. Among the issues remaining to be resolved are wear and periprosthetic osteolysis after total joint arthroplasty. Today's researchers are investigating the pathogenesis and reduction of osteolysis and wear, and practitioners and engineers are working together to develop new types of prostheses for total hip and knee arthroplasty. This book presents the work of eminent orthopedic surgeons, biomedical engineers, and other researchers who have devoted their efforts to the creation and implementation of more durable total joint prostheses. The latest information on new concepts and clinical trials is included, with chapters on ostcolysis, recent developments in metal-on-metal and ceramic-to-ceramic articulation, and future trends in total joint arthroplasty.

The introduction of total joint arthroplasty throughout the world has contributed manifold benefits to patients who suffer from joint diseases. Concurrently, however, there has been an increase in revision surgery. Many orthopedic surgeons agree that durability of prostheses is an eternal problem. In particular, periprosthetic osteolysis recently has been identified as one of the serious problems affecting prosthetic dura bility. To improve durability, osteolysis and many other problems must be investi gated and solved both experimentally and clinically with respect to such aspects as prosthetic material, design, and biological and biomechanical behavior. This book comprises 37 papers that were presented by orthopedic surgeons and biomedical engineers at the 28th Annual Meeting of the Japanese Society for Replace ment Arthroplasty, held in March 1998 in Kanazawa, Japan. The volume is thus a compilation of the latest knowledge about the pathogenesis and reduction of osteolysis and wear, newly developed total hip prostheses, and other current topics of total knee arthroplasty. We earnestly hope that this book will be of benefit to clinicians and researchers, and that it will contribute to the creation of more durable total joint prostheses in the future. SHINICHI IMURA v Contents Preface .................... '" .. .. .. ... . .. .. .. . ... .. . . .. . ... . . .. . V List of Contributors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XI . . . . . . . . . . . . Part 1 Wear and Pathogenesis of Osteolysis Friction and Wear of Artificial Joints: A Historical Review N. AKAMATSU ................................................, 3 Matrix Degradation in Osteoclastic Bone Resorption Under Pathological Conditions ."

It was a great honor for us to preside over the Hip Biomechanics Symposium, held on November 19, 1992, in Fukui City, Japan. We believe it was the first interdisciplinary conference on biomechanical approaches to hip disorders; this volume contains the presentations made at the conference. The information found here will be of value not only for orthopedic surgeons but also for researchers. The advent of biomechanical approaches to hip dis ease has made possible the understanding of fundamental hip pathologies, an understanding which enables us to institute the appropriate non-surgical or surgical treatment. Indeed, efficient surgical planning is not possible without taking these approaches. This comprehensive volume consists of six major sections: loading, gait analyses, THA, osteotomies, motion analyses, and stem designs for stability. Each of these sections brings together many of the leading researchers in this field. We hope this volume will be a spur to future understanding of and on fruitful research on hip disorders. The Editorial Committee wish to express their deep gratitude to the contri butors and the publisher. Shinichi Imura Noriya Akamatsu Hirohiko Azuma Kazuhiko Sawai Seisuke Tanaka v Table of Contents Preface......................................................... V I Hip Joint and Loading 1 Two-Dimensional Finite Element Analysis for Stress Distribution in Normal and Dysplastic Hips Nobuo Konishi.. . .. . . . . . .. . . . . . .. . . . . . . . . . .. . . . . . .. . . . . . . . . . 3 2 Stress Distribution at Hip Joint During Level Walking Kazuhiko Sakamoto, Yoshinobu Hara, Akira Shimazu, and Kenji Hirohashi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 . . . . . . . . . . . . . . 3 Biomechanical Studies of the Hip Utilizing Computer Simulation Takatoshi Ide, Yasuhiro Yamamoto, and Shigeru Tatsugi . . . . . . . . . 21 ."