| Objective：The posterior cruciate ligament(PCL) injury without effectivetreatment will cause the late-occurred knee joint degenerative change, andsurgery was recommended for severe PCL injury. The clinical effect of thesingle bundle PCL reconstruction deserves affirmation through a lot oflong-term clinical follow-ups.The ideal PCL anatomy reconstruction is to restore the normalphysiological functions of the original PCL including the original size, thedirection of the fiber, the tension of the graft, and the size of the attachment.The bone tunnel aperture morphology was influenced by tunnel diameter, theangle between the guide needle and the local interior notch wall, and kneeflexion angle. It is no doubt that the tunnel aperture morphology wasinfluenced by the tunnel diameter. The angle between the guide needle and thelocal interior notch wall is mainly related to the "acute angle"effect, but it isdifficult to measure the accurate angle in the operation. The tunnel aperturemorphology is an important part of the anatomical PCL reconstructionorientation in the articular cavity, and it is easy to conduct in the operation.There are few studies on this aspect at present.This study was designed to explore the relationship between the kneeflexion angle and the angle formed by the long axis of femoral tunnel aperturemorphology and the normal PCL femoral attachment point in PCLreconstruction, and provide some suggestions for surgeons to choose thereasonable bone tunnel position to make the bone tunnel aperture morphologymore close to the normal PCL anatomical structure.Meterials and Methods:20cases of specimens knee joints. All specimenswere provided by the Third Affiliated Hospital of Hebei Medical University.All the specimen were fixed in homemade adjustable knee fixed bracket, marked and recorded the knee flexion angle. Single bundle PCLreconstruction was conducted in this study, and the central point of the footprint was chosen as the guide needle position at femoral side. First of all, theknee joint was fixed at70°flexion in the bracket, and the central point of thefoot print was chosen as the guide needle position. Use the lateral approachesas the entrance of the drill, and make the kwire and the local bone wall about70°angle. The kwire's position was located at a horizontal position withconventional arthroscopy lateral approaches. After the kwire was locatedthrough the contralateral bone cortex, check the located position and the fixedangle, make some adjustment if the deviation happened. To ensure that thespecimen can be repeated and the data accuracy can not be affected, bonetunnel was actually set up using a homemade tunnel simulator(simulating atunnel drill with10diameter) in this study.Measure and record the degree ofangle between the bone tunnel long axis and long axis PCL femoral footprint,then confirm the mismatched exist (the bone tunnel aperture morphologyover the normal PCL foot print) through visual observation. After themeasurement, take out the guide wire, and be careful not to damage otherstructures. Check whether the kwire bending or not, replace it with a new oneif it is bended.Fix the knee joint at90°through adjusting bracket.Choose the sameposition as the knee joint flexion at70°, make the kwire and the local bonewall form70°. The kwire's position is located with conventional arthroscopylateral approaches and record the degree of angle between the bone tunnellong axis and PCL femoral foot print long axis after the kwire was through thecontralateral bone cortex, then make sure the bone tunnel aperture morphologywas not beyond the normal PCL foot print by visual inspection. After this, takeout the guide wire and check it or replace it. Measure and record the datausing the same method above when the knee joint flexion was respectively at110°and130°.Statistical analyses were performed with SPSS13.0(SPSS Inc.,American).The angle of bone tunnel long axis and PCL femoral foot print long axis were compared using the Rank conversion of parametric test and SNK-qtest and the mismatched rate using the Fisher's Exact Test among differentknee joint flexion degrees.Results: The angle between tunnel aperture morphology's long axis andthe normal foot print's long axis was respectively70.15°±4.16°,57.26°±4.24°,45.39°±7.27°,29.95°±7.27°when the knee joint flexion was at70°,90°,110°,and130°. The Rank conversion of parametric test for knee orientation angleamong different groups showed significant difference(p<0.00). SNK-q testwas used to compare among groups, and the results showed that there weresignificant difference (P=1.00).There were3cases when bone tunnel aperture morphology was beyondthe scope of the normal PCL foot print, the tunnel diameter was10mm and theknee flexion was at70°(15%);1case at90°(5%); there are no mismatch at110°and130°.Fisher's Exact Test was used to compare the mismatch between bonetunnel morphology and normal ligament attachment at different angles. Theincidence of mismatch was lower when the knee flexion was at70°,90°,110°and130°, and concentration happened in the smaller knee flexion. There areno significant difference among different knee flexions(t=4.505,p=0.185).Conclusions: There are few studies on relationship of tunnel aperturemorphology and normal footprint morphology, and more studies focused onreproducing the position of the normal PCL femoral attachment at present.Our study showed that the long axis of tunnel aperture morphology wasdifferent when the knee flexion changed, even in the same tunnel position.Due to the change of orientation of the long axis of the tunnel aperturemorphology, there are a subset of cases whose tunnel aperture coverage arebeyond the normal PCL foot print area, which caused the mismatch on theeffective reconstruction area. The further research was needed to study thecause of mismatch and its influence on biological mechanics and long-termclinical effects. Our study showed that the effect of knee flexion on theorientation and area of long axis should be noticed in the PCL reconstruction, and better outcome can be obtained knee flexion was at130°, when tunnelposition can make the tunnel aperture morphology more close to the originalPCL's anatomy. |
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