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assumed to be 0.6. The distal portion the tibia was rigidly constrained. Five activities weresimulated based on data from Orthoload.com (patient K1L) including walking, stair ascent, stairdescent, sitting down and a deep knee bend. The three force and three moment time historieswere discritised to give between 44 and 48 individual load steps. Custom written scripts wereused to generate composite peak micromotion plots, which report the peak micromotion thatoccurs at each point of the contact surface during the gait cycle. The primary stability was thenassessed by reporting the maximum micromotion, the average peak micromotion and thepercentage of the contact area experiencing micromoitons less than 50 microns.Results and discussion: Similar trends were observed for all three designs across the range ofactivities. Stair ascent and descent generated the highest micromotions, closely followed bylevel gait. Across these three activities the mean peak (maximum) micromotions ranged from64-78 (186-239) microns for PFC Sigma, 61-72 (199-251) microns for Duofix and 92-106(229-264) microns for LCS. The peak micromotions did not necessarily occur at the peakloads. For instance, for level walking the peak micromotions occurred when there were lowaxial forces, but moderate varus-valgus moments. This highlights the need to examine thewhole gait cycle in order to properly determine the initial stability tibiae tray designs. Byexploring a range of activities and interrogating the entire contact surface, it is easier todifferentiate between the relative performance of different implant designs.Saturday, October 9, 2010, 8:15-9:00Session A17: Knee MechanicsKinematic Analysis of Mobile-Bearing Total Knee Arthroplasty UsingImage Matching TechniqueKatsumasa Tei - Kobe Kaisei Hospital - Kobe, JAPAN*Nao Shibanuma - Kobe Kaisei Hospital - Kobe, JAPANSeiji Kubo - Kobe University - Kobe, JapanTomoyuki Matsumoto - Kobe University Graduate School of Medicine - Kobe, JapanAkio Matsumoto - Kobe Kaisei Hospital - Kobe, JAPANHiroomi Tateishi - Kobe Kaisei Hospital - Kobe, JAPANMasahiro Kurosaka - Kobe University Graduate School of Medicine - Kobe, JapanRyosuke Kuroda - Department of Orthopaedic Surgery, Kobe University Graduate School ofMedicine - Kobe, Japan*Email: shibanu@db4.so-net.ne.jpAchieving high flexion after total knee arthroplasty (TKA) is one of the most important clinicalresults, especially in eastern countries where the high flexion activities, such as kneeling andsquatting, are part of the important lifestyle.Numerous studies have examined the kinematicsafter TKA. However, there are few numbers of studies which examined the kinematics duringdeep knee flexion activities. Therefore, in the present study, we report analysis of mobilebearingTKA kinematics from extension to deep flexion kneeling using 2D-3D image matchingfile:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]