| Background and Objection:The Rigidfix cross-pins system can provide effective stablility in the ACL reconstruction.The Rigidfix cross-pins system can fix the grafts at the site near the ACL physiological attachment point and thus achieve anatomic reconstruction.Some authors produced the ACL reonstruction using the Rigidfix cross-pins system at the tibial side,and achieved the satisfactory result of biomenchanical test,and decreased the revision rate,as well as,graft length requirement in the ACL reconstruction can be reduced accordingly.But the anatomic study about its safety is still lack.The mainly objection of the study invested the iatrogenic damages incidence rates when the Rigidfix fixation system applied at the tibial side through the research of the anatomy.According to this research,we aim to fill in the gap about the basic study of this technique,and to provide the reference for clinical application,ang to popularize the technique in the basic hospitals.Methods and materials(1).The eleven adult conservative cadaver knees were performed using the Rigidfix Cross Pins device at the tibial fixation side for modeling the ACL reconstruction.The guide rod top was put through the tibial tunnel at the three horizontal positions:equal pace to articular facet(group A),the plane 5 mm below articular facet(group B),and the plane 10mm below articular facet(group C).We gave four rotation positions to the cross-pins guide:0°,30°,45°,60° slope,referring to the parallel line of the posterior border of tibial plateau.We recorded the iatrogenic damages incidence,in the four different slope angle in the three groups.(2).Camparing the the iatrogenic damages incidence of the two different groups that the Rigidfix cross-pins guide through the traditional tibial tunnel and the new-style tibial tunnel.Five adult fresh cadaver knees were fixed with the Rigidfix cross-pins at the tibial fixation side during ACL reconstruction.Two different tibial tunnel groups were established:in group A,the tunnel external aperture was placed at the 25° angle of coronal section,and in group B the tunnel external aperture was placed at the 45°angle of coronal section.The guide was placed at the plane 0.5mm below articular facet through the tibial tunnel,with three rotation positions set at 0°,30°,and 60°slopes.The incidences of iatrogenic injuries at tibial plateau cartilage(TPC),medial collateral ligament(MCL),and patellar tendon in three different slope angles were calculated in groups A and B.Results:(1).The incidence of chondral injury of tibial plateau in group B and group C was significantly lower compared to group A(?2A-B=27.077,?2A-C=45.517,P=0.000);However,there was no significant difference for the incidence penetrating the medial condyle of tibial plateau among the three groups(?2=5.733,P=0.057);The highest incidence of injuring ligamentum transversum is in group A(?2=28.840,P=0.000)with 29.5%.In group A,The highest incidence of injuring ligamentum transversum is at the 60° slope angle(?2=13.226,P=0.004)with 72.7%.(2).The iatrogenic injuries at MCL,TPC,and patellar tendon could occur after the Rigidfix cross-pins system was placed 5mm below tibial plateau cartilage for ACL reconstruction.The incidences of TPC injury(?2=5.662,P=0.017)and MCL injury(P=0.048,Fisher exact probability method)were significantly lower in group A than in group B.However,the incidence of patellar tendon injury showed no significant difference between these two groups(?2=0.120,P=0.729).Conclusion(1).Our study suggested that in order to achieve the satisfactory clinical effect for the Rigid-fix system used in the tibia end fixation of ACL reconstruction surgery,the guide rod top should be put at the 5mm below articular facet.(2).When the Rigidfix cross-pins system is used for ACL reconstruction at the tibial fixation site,the external aperture of tibial tunnel should be placed at the 25°angle of coronal section,so as to avoid MCL and TPC injuries. |
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