Accurate fluoroscopic technique in tibial intramedullary nailing and preliminary clinical vali-dation

Qiao Chang; Xue Kaixiao; Zhu Bin; Cai Bowen; Yang Zhenqi; Song Lijun; Fang Jiahu

doi:10.3969/j.issn.1009-4237.2025.10.008

Abstract：Objective Based on preoperative knee CT scans,measure and analyze the relevant anatomy in-volved in the tibial intramedullary nail entry point,determine the optimal intraoperative fluoroscopic angle,and per-form preliminary clinical validation.Methods A retrospective analysis of 86 knee CT scans from June 2018 to June 2022 at the First Affiliated Hospital of Nanjing Medical University.There were 49 males and 37 females;ages ranged from 18 to 65 years,with a mean of 53.4 years.Compare the angle α1 between the line L1,connecting the midpoint O of the tibial spine and the tibial tubercle A,and the line L2,the posterior line of the tibial plateau(inner and outer sides of the posterior condyle)and the line L4(the fluoroscopic line perpendicular to the fibular head).Also compare the ratio La/Lb/Lc,where La is the length of the segment of L2 passing through the maximal plane of the fibular head,and Lb/Lc is the ratio of the horizontal distance from the fluoroscopic line to the fibular head on both sides,measured by the line through the outermost edge of the tibial plateau and parallel to the tibial spine line(the inner-to-outer length ratio).In the CT axial plane,determine the angle α3 between the fluoroscopic line L4 shown by the tibular bisector line method and the direction of the line from the midpoint O of the tibial spine to the tibial tubercle A(the fluoroscopic angle difference).Results α1<α2(P<0.001).There were no obvious differ-ences between sexes in the intramedullary nail entry-point related measurements(La,Lb/Lc)(P>0.05).On the maximal plane of the fibular head,the angle α3 between the L1 fluoroscopic line and the L4 fluoroscopic line was 7.38±2.67 in males and6.34±2.15 in females,with a statistically significant difference(P<0.001).The line be-tween the midpoint O of the tibial spine and the tibial tubercle A forms a perpendicular relationship with the posteri-or condylar line on the maximal plane of the tibial plateau.In standard anteroposterior knee radiographs,the distance ratio from the lateral tibial edge to the fibular head on both sides can be considered 2:1.Conclusion During tibial intramedullary nail surgery,fluoroscopy using the standard lateral view corresponding to the overlap of the medial and lateral femoral condyles,rotated 90 to one side,yields the optimal frontal fluoroscopic orientation,significantly reduc-ing the number of intraoperative fluoroscopic exposures and preventing positioning differences from affecting needle-entry point localization.