| Objective： The arthroscopic anterior cruciate ligament (ACL)reconstruction has been one of the most common surgerys. There are manycontroversys to get perfect clinical outcomes after ACL reconstruction, such asthe choice of graft, the fixation type, the drilling of the bone tunnel, single-ordouble-bundle reconstruction technique and so on. Theoretically, anatomicdouble-bundle ACL reconstruction could get the best result, however, it ismuch more technically demanding and requires more surgical time andexpertise, it is also more expensive than single-bundle ACL reconstructionbecause of longer surgical time and more fixation material. All theselimitations inhibit its generally clinical application. To improve the clinicaloutcomes of the single-bundle reconstrution, much attention has been directedtoward recreate the femoral ACL footprint, and generally advocate thatfemoral tunnle selects the center of native ACL footprint, however,considerably less focus has been placed on tibial tunnel position.In the current study, we performed the single-bundle ACL reconstrutionwith a central femoral tunnel and2different tibial attachment positions: thecentral tibial tunnel and the anteriormedial tunnel. And then both comparedwith anatomic double-bundle reconstrution. The purpose of the study is to findthat if the anteriormedial tibial tunnel could get better stability than the middletunnel with a central femoral tunnel.Methods：Totally15fresh-frozen cadaveric knees were used in the study,and all of the specimens were examined for fracture, deformities, osteoporosis,tumors, ligamentous integrity, and the absence of significant meniscal andarticular cartilage lesions. Each specimen was randomized into1of the3reconstruction procedures, according to the obtained order: the first, group A; the second, group B; the third, group C; the four, group A; and so on. All thespecimens which in group A were performed anatomic double-bundle ACLreconstruction, which in group B and group C were performed single-bundleACL reconstruction with the central femoral tunnel. In group B, the tibialtunnel was located in the mid-point of the ACL footprint, while in group C,which was located in the anteromedial aspect of the ACL footprint. Both thedistal femur and proximal tibia approximate20cm from the joint line werereserved for each specimen, and the fibula was fixed on the tibia with aKirschner wire. The Achilles tendon was harvested from each specimen andprepared as autograft. Knee specimens were fixed in a homemade five degreesof freedom adjustable bracket, a medial parapatellar arthrotomy of the kneewere performed, the ACL were carefully removed and1~2mm of the stumpboth the femoral and tibial side were preserved.Group A: All specimens were performed anatomic double-bundlereconstruction, both the femoral and tibial tunnels were placed in anatomicalposition of the ACL attachment. Under the direct vision and at90°of kneeflexion, the anteromedial bundle(AMB)was located at11o'clock (right knee)or1:00(left knee) direction and a distance of approximate3~5mm from theedge of the intercondylar notch cartilage. The posterolateral bundle(PLB)waslocated at10:30(right knee) or2:30(left knee) direction and a distance ofapproximate8mm from the edge of the intercondylar notch cartilage.Subsequently, with the knee held at130°of knee flexion, the femoral AMtunnel was created by use of cannulated drills attached to the RetroButtonsystem, with the7mm diameter, and then the PL tunnel was created with the6mm diameter, while maintaining an at least2-mm bony bridge betweenbundles. In drilling the tibial bone tunnels, the inclination of the drill guidewas set at45°for both tunnels, whereas in the axial plane, the direction wasinclined from the anteroposterior tibial axis by20°and45°for the AM and PLtunnels, respectively. For graft fixation, we used the RetroButton for thefemoral side, and the interference screw for the tibial side. During tibialfixation, we fixed the PLB first, while a maximum manual tension was simultaneously applied to both grafts at approximately20°of knee flexion.Group B: All specimens were performed anatomic single-bundlereconstruction, both the femoral and tibial tunnel were placed in the centerposition of the ACL attachment. Under the direct vision and at90°of kneeflexion, the femoral tunnel was located at1o o'clock (right knee) or2:00(leftknee) direction and a distance of approximate6mm from the edge of theintercondylar notch cartilage. The drilling of the tunnels, the fixation materialsand the fixation way were as previously described for Group A. The bonetunnel diameter was8mm.Group C: All specimens were performed single-bundle reconstruction,the tibial tunnel were placed in the anteromedial position of the ACLattachment. Others were as the same as descrubed for Group B.All the specimens were fixed on a homemade five degrees of freedomadjustable bracket. The specimen was fixed on the CSS-44020biomechanicaltest machine (China) and Electroforce3520-AT (Bose, American) in sequence.The anterior-posterior shift and the internal rotation angles were measuredrepectively when knee joint was bend at0°,15°,30°,60°and90°. A constantload of134N was applied to the tibia and the shift speed was50mm/min. A3Nm torque force was applied to the tibia to measured the internal rotationangles. The tibial anteroposterior translation and internal rotation angles weremeasured and recorded.The statistics were described by mean±standard deviation. One-wayanalysis of variance was performed between the3groups. The level ofsignificance was set at α=0.05.Results: Statistical results of the tibial anteroposterior translation indifferent flexion angles on each group with the constant anterior load of134Nas follows: Group A displayed a better control of the anterior stabilitycompared to group B in all the flexion angles (P<0.05), when compared togroup C, group A showed better control of the anterior stability only in0°and15°of knee flexion, there was no statistically significant between groups in30°,60°and90°of knee flexion. For group B and C, the latter was significantly better than the former (P <0.05) in30°,60°and90°of kneeflexion.Statistical results of the tibial internal rotation angles in different flexionangles on each group a3Nm torque force as follows: Group A displayed abetter control of the internal rotation stability compared to group B in all theflexion angles (P<0.05), when compared to group C, group A showed bettercontrol of the internal rotation stability only in0°,15°and30°of knee flexion,there was no statistically significant between groups in60°and90°of kneeflexion(P>0.05). For group B and C, the latter was significantly better thanthe former (P <0.05) in60°and90°of knee flexion.Conclusions: Anatomic double-bundle ACL reconstruction could getbetter knee stability than single-bundle reconstruction instantly after theoperation, including anterior and internal rotational stability. For single-bundlereconstruction, when a central femoral tunnel is used, placement of the tibialtunnel in the anteriormedial aspect of the native footprint could better controlthe tibial anterior and internal rotation stability of than placement of the tibialtunnel in the middle aspect of the tibial footprint in the larger kneeflexion(such as60°,90°), but more attention should be directed toward theintercondylar notch impact. |
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