Convened under the auspicious of esteemed endorsers - ISTA

Friday, October 8, 2010, 16:30-17:20Session A16: Computer Navigation in THAEvaluation of the Stem Position of Total Hip Arthroplasty With CT-BasedNavigation SystemYoshiaki Miyake - Okayama University - Okayama, Japan*Kazuo Fujiwara - Okayama University Hospital - Okayama, JapanHirosuke Endo - Okayama University Graduate School of Medicine, Dentistry, andPharmaceutical Sciences - Okayama-city, JapanToshifumi Ozaki - Okayama University Hospital - Okayama, JapanShigeru Mitani - Kawasaki Medical School - Kurashiki-city, Japan*Email: fujiwara@md.okayama-u.ac.jp(Objectives) Many reports were shown about the angle of the cup in total hip arthroplasty(THA) with CT-based navigation system. However, there are few reports about the position ofthe stem. We investigated the position of the stem in navigated THA. We evaluated the positionand alignment of stem which were shown on intra-operative navigation system.(Materials and Methods) We treated 10 hips in 10 patients (1 male and 9 females) by navigatedTHA. 7 osteoarthritis hips and 3 idiopathic osteonecrosis hips were performed THA withVectorVision Hip 2.5.1 navigation system (BrainLAB). Implants were AMS HA cups andPerFix stems (Japan Medical Materials, Osaka). The positions of stem were decided on the 3Dmodel of femur before operation. According to the preoperative planning, we put the implantswith navigation system and recorded the position. We measured the position and alignment ofstem with 3D template software after operation. We checked for complications.(Results) The average error of stem alignment was 0.9 degrees in anteroposterior direction, 1.2degrees in mediolateral direction and 3.5 degrees in rotation. The average error of the distancebetween the tip of greater trochanter and the shoulder of stem was 1.6mm on postoperative CT.Though there were no infections and fractures, 7 cases had postoperative pain on the lesionwhere we insert tracker pin.(Conclusions) The accuracy of longitudinal stem alignment was correct but the anteversionvaries widely. We usually perform THA by minimally invasive technique. Therefore thereference points of proximal femur were restricted at narrow area for registration and thelandmarks for deciding the rotational alignment were difficult to be picked up correctly.Saturday, October 9, 2010, 10:30-11:05Session B18: Pot Pourri!Controlled Release of Antibiotics From Beta-TCP Mixed in HA in IBBC asPrevention of Infection in Joint Replacement*Shigekazu Mizokawa - H. Oonishi Memorial Joint Replacement Institute, Tominaga Hospital -file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]