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198.5±5.5°and 157.0±7.5°, respectively. After provided informed consent, each subject wasasked to perform a weight-bearing knee bend to maximum flexion under radiographicsurveillance in the sagittal plane. The 3-D bone models of the femur and tibia, generated bysegmentation from CT images, were projected onto the radiographic images and their 3-Dpositions and orientations were determined. We evaluated the following parameters: maximumflexion angle, tibiofemoral rotation, and antero-posterior translation of the medial and lateralfemoral condyle.RESULTS:Maximum flexion for 6 subjects with varus deformity and 7 subjects with valgus wereaveraging 97.3±28.3°and 112.1±31.3°, respectively, however not statisticallysignificant(p=0.95). 3 out of 6 varus knees showed small internal rotation pattern from fullextension to maximum flexion and the rest of 3 knees exhibited paradoxical external rotationfrom mid flexion to terminal flexion. On average, tibial internal rotation was, 0.38±7.2° fromfull extension to maximum flexion. In addition, posterior translations of femoral condyles wereconfirmed in all cases and the averaging lateral condylar translation was slightly greater thanmedial condylar translation, 9.4±11.3mm and 7.7±7.4mm, respectively (p=0.41). However,paradoxical anterior translations were confirmed in 2 knees during mid-flexion. In contrast, 5 of7 valgus knees experienced external tibial rotation patterns from full extension to maximumflexion and 2 knees showed reversed rotation patterns during mid-flexion. On average,the tibialexternal rotation was 4.7±7.6° from full extension to maximum flexion. Moreover, the averagecondylar translation was greater in the medial condyle than in the lateral condyle, 6.9±9.7mmand 3.9±13.8mm, respectively(p=0.23) and 4 knees exhibited paradoxical anterior translationsduring mid-flexion.DISCUSSION:According to previous reports, flexion of the nonarthritic healthy knee is associated withposterior rollback of the femoral condyle and internal rotation of the tibia. Our results of bothvarus and valgus knee kinematics were different from those seen in previous reports. Inaddition, there were few reports about the kinematics of osteoarthritic knees, in which the axialrotation were lost and the loss of rotation might be associated with the severity of arthritis. Ourresults of varus knee kinematics were high variable and were similar to patterns previouslyreported for osteoarthritic knees. However, the kinematics experienced in valgus knees weredifferent from those reports. The result of this study suggests that these kinematics establishedin advanced arthritic knees might have influence postoperative kinematics.Poster: 45Hinged Knee Arthroplasty in Revision Knee Surgery: Still Up to Date*Wolfgang Klauser - Endo Klinik - Hamburg, Germany*Email: Wklauser@t-online.deHinged Knee Arthroplasty in Revision Knee Surgery: Still Up to Date?file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]