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were balanced to within 2° to 3° in extension. A distractor with 2 flat independent plates wasapplied to measure the gap into both medial and lateral compartments of knees in extension andthen in flexion, and gaps were measured and recorded. In measured group we started theprocedure on the tibia referencing to Witheside. The trial components were inserted and theknee tested throughout a complete range of motion: then, whatever ligament balancing wasnecessary, was performed. Final balance, alignment, and range of motion were measured andrecorded using the navigator.The difference between the pre-operative and post-operative jointline (JL) was considered as primary outcome for comparison between the groups.The joint line(JL) was calculated as the perpendicular distance from the tibial tubercle to the tibial plateau(pre-operative JL) or a line parallel to the weight-bearing surface of the prosthetic tibialcomponent (post-operative JL), on lateral radiographic view. The long-leg x-Ray the hip-kneeangle(HKA), the frontal femoral component (FFC) angle and the frontal tibial component(FTC) angle were recorded. The lateral femoral component (LFC) angle and the lateral tibialcomponent (LTC) angle were measured.All radiographs were recorded by five physicians.Nocomplications related to the navigation system occurred. Statistical analysis comparing the ratioof the preoperative and postoperative joint line showed no differences between the groups interms of repeatability, but comparing the Gap balanced groups (PS and CR) with CR MeasuredGroup using the differences between the pre-operative and post-operative joint lines, asignificant prevalence (P= 0.016) of measured resection technique in preserving the JL originalvalue was observed. The mean raising of the joint line was 3.2 mm (± 1,6) in the gap groupsand 2.1 mm (± 1,2) in the measured group.We observed a significant difference in the joint lineposition postoperatively between the 2 techniques. The measured resection techniquemaintained a post-operative level of joint line closer to the original preoperative value.However, the amount of modification was moderate with both surgical approaches. There is nopublished evidence in the literature that shows that minor changes such as these in the joint lineposition in primary TKA have an effect on the clinical outcome.Poster: 87In Vitro Tests in Order to Evaluate the Effect of a Femoral Stem With anIntertrochanteric Plate*Rina Sakai - Kitasato University - Sagamihara, JapanMoritoshi Itoman - Kyushu Rosai Hospital - Kitaksyushu, JapanHakuhiko Maezawa - Tokyo Maezawa Orthopaedic Surgery - Suginami, JapanKiyoshi Mabuchi - Kitasato University - Sagamihara, Japan*Email: Rinax@kitasato-u.ac.jpIntroduction To prevent loosening during the long-term use of femoral stems, stems with aplate or collar for mechanical fixation have been developed. The advantage of femoral stemswith a collar is force transmission in the proximal area, but their appropriate contact with boneis difficult to achieve. There is a possibility that this problem can be overcome using anintertrochanteric plate devised by Dr. Maezawa in 1968. Contact between bone and jointprostheses is difficult to interpret because the general contact theory cannot be applied to thiscontact. Therefore, in this study, pressure, stress, and micromotion were used as parameters forfile:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]