A radiological comparative study between transtibial & anteromedial portal drilling of femoral tunnel in single bundle anterior cruciate ligament reconstruction: A comparison of four angles

Abstract

Femoral tunnel drilling for graft insertion is performed by transtibial or transportal technique. AimMain objective of this study was to compare the postoperative anteroposterior and lateral radiographs after arthroscopic ACL reconstruction by transtibial and transportal techniques by measuring four angles. Materials and methodsA retrospective study of 60 patients was conducted, who were further subdivided into two groups containing 30 each. The first group had patients who had undergone arthroscopic ACL reconstruction by transtibial technique and the second group had patients who had undergone ACL reconstruction by transportal technique. Post-operative anteroposterior radiographs (AP) and lateral radiographs of the operated knees were compared. Condylar tunnel (CT) and tunnel screw (TS) angles were measured in AP radiographs and compared. In lateral radiographs, shaft tunnel (ST) and TS angles were measured and compared. ‘Student t-test’ was used in calculating the results. ResultsMean of the angles measured were tabulated and compared. CT angle was noted to be more acute in transportal group (38.4±8.756°) as compared to transtibial group (46.97±12.754°) with a significant ‘p-value’ (0.004). ST angle was noted to be more obtuse in the transportal group (119.57±11.212°) as compared to transtibial group (113.17±12.793°) with a significant ‘p-value’ (0.044).This infers that transportal technique oriented the graft more horizontal as compared to transtibial technique.Tunnel screw angles when compared in AP radiographs showed that transportal technique (5.5±4.644°) had more acute angulation as compared to transtibial group (12.57±8.287°) with a significant ‘p-value’ (<0.001). Same results were obtained when the lateral views were compared between transportal (9.27±8.25°) and transtibial technique (23.73±12.174°) with a significant ‘p-value’ (<0.001). This indicated reduced screw tunnel divergence in transportal technique as compared to transtibial technique. ConclusionTransportal technique results in a more anatomical femoral tunnel placement as compared to transtibial technique.