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Advances in Fuzzy Systems
Volume 2012, Article ID 201248, 8 pages
Research Article

Fuzzy Support System for Total Hip Arthroplasty Stem by Ultrasonic Intraoperative Measurement

1Department of Electrical Engineering and Computer Sciences, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
2Division of Information Systems, WPI Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
3Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3-11-15 Shinohara Kitamachi, Nada-Ku, Kobe, Hyogo 657-0068, Japan

Received 17 August 2012; Accepted 24 September 2012

Academic Editor: Arianna Mencattini

Copyright © 2012 Naomi Yagi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper describes a fuzzy system of stem implantation on total hip arthroplasty by an ultrasonic device. The system can perform automatic and accurate assessment in the surgery. In this system, we employ a single ultrasonic probe whose center frequency is 1,000 Hz. We detect the acoustic signals when knocking the inserted stem with a hammer. We then have a correlation between the degree of tightening and the attenuation time of acoustic signal. That is, the higher tightened degree implies shorter attenuation period. The support system selects the most suitable stem size by fuzzy inference with respect to the attenuation time and its difference time from correct stem to one larger size stem which dynamically adapts to each patient. As a result, we successfully determined the suitable stem in comparison to the results of the practical surgery.