| ObjectiveTo investigate the best knee flexion angle by analyzing the length and orientationof femoral tunnel through anteromedial portal(AM) at different flexion angles duringanterior cruciate ligament(ACL) reconstruction. To determine whether the AM andOutside-in(OI) techniques in ACL reconstruction differ in femoral tunnel length, thetunnel position in lateral femoral wall, tunnel orientation in the anteroposterior-,lateral-view radiographs. And explore the relationship between femoral tunnel lengthand the size of the femoral condyles. Provides the certain reference value for clinicalACL reconstruction.Method:1Random measurement of90cases about the maximum flexion of the kneeabout healthy adults from three different age group, and use in the experiment of kneeflexion angle.2Fifteen fresh frozen cadaveric knees that under normal temperature for24h,were selected to locate the center of ACL femoral footprint through AM using theimproved hook slot vernier caliper and to locate the posterior bone cortex using adiameter3mm ball at different knee flexion angles. The femoral tunnel length,standard coronal and sagittal plane angle, the position relation between exit point andthe lateral femoral epicondyle(LFE), the tunnel orientation in the anteroposterior-view,lateral-view radiographs were measured.3Using the improved hook slot vernier caliper positioning the center of ACLfemoral footprint through an accessory AM and OI respectively. Using a diameter3mm ball to positioning the footprint and posterior bone cortex. The femoral tunnellength, the position relation between exit point and the LFE, tunnel orientation in the anteroposterior-view, lateral-view radiographs, the width of femoral condyles and thesize of lateral femoral condyles were measured.Results:1The maximum flexion of the knee about healthy adults among the three groupsis greater than130°, there is no significant difference between them (P>0.05).2With the increasing flexion of knee, the femoral tunnel length showed a firstincreasing and then stable tendency. The results had significant difference between90°and other flexion angles, either between100°and120°(P<0.05). The exit pointof the femoral tunnel located at the lateral epicondyle of the femur proximal toposterior region at flexion of90°in all knees, and at flexion of100°in7knees, butit located at the lateral epicondyle of the femur proximal to anterior region at flexionof110°~130°in all knees. The femoral tunnel showed a trend of decreasing withcoronal angle, whereas gradually increasing with sagittal angle. The knee flexionangle had significant difference either among flexions of90°,100°,and130°orbetween flexions of100°and120°(P<0.05). As the knee flexion angle increasing,the angle between femoral tunnel with the tangent of internal-external femoralcondyle on frontal X-ray films showed a trend of decreasing gradually, but a trend ofincreasing gradually on lateral X-ray films. On the frontal X-ray films, significantdifferences were found in the angle either among flexions of90,110, and130°orbetween flexions of100°and120°(P <0.05), but no significant difference among theother angles (P>0.05). On the lateral X-ray films, there were significant differencesin the angle among90,100,110,120, and130°(P <0.05).3The femoral tunnel length was(36.90±2.54)mm when using OI, but was(35.05±2.13)mm when using AM. The results had significant difference between them(P<0.05). The points on lateral femoral wall were located in the proximal-front oflateral epicindyle. OI was closer to the heart distribution than AM. But AM was moreconcentrated. The width of femoral condyles and the size of lateral femoral condyleswere both positively related with the intraosseous length.Conclusion:1During ACL reconstruction by AM,110°is the ideal flexion angle which can get the ideal femoral tunnel. The femoral tunnel length can satisfy the requirements ofEndobutton.2Both of OI and AM can satisfy the requirements of ACL reconstruction forfemoral tunnel. The femoral tunnel length of OI is longer than AM. But by AM, thetunnel points of lateral femoral condyle wall is more concentrated.3OI is more casual, not influenced by the flexion of knee. Sergeons can usedifferent operation method according to specific circumstances. |
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