Comparison of 4 Femoral Tunnel Drilling Techniques in Anterior Cruciate Ligament Reconstruction

An in Vivo 3D Computed Tomographic Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique

“…The femoral tunnel length determines how much graft remains in the femoral tunnel when conventional suspensory fixation devices are used. 10 Because this conventional suspensory fixation device occupies 15 mm for dead space and because of loop length, if the overall tunnel length was less than 30 mm, the graft length in the tunnel would be less than 15 mm. There is little evidence available to determine whether a tunnel graft length less than 15 mm is safe for ACL reconstruction, particularly in humans.…”

“…7,8 The flexible system has theoretical advantages over the rigid system, including longer femoral tunnel length, further distance from the neurovascular or lateral structures of the knee, and a decreased possibility of injuring the cartilage of the medial femoral condyle. 7,[9][10][11][12] Additionally, the flexible system can be used without forcing a hyperflexed position on the knee, which allows for improved visualization over the rigid system. 7 Many previous studies have compared femoral tunnel length between the rigid and flexible systems, [9][10][11][12] and most reported a significantly longer femoral tunnel length using the flexible system in cadaveric studies.…”

“…7,[9][10][11][12] Additionally, the flexible system can be used without forcing a hyperflexed position on the knee, which allows for improved visualization over the rigid system. 7 Many previous studies have compared femoral tunnel length between the rigid and flexible systems, [9][10][11][12] and most reported a significantly longer femoral tunnel length using the flexible system in cadaveric studies. 9,11,12 The femoral graft-bending angle determines the bending stress of the graft and may cause graft damage and tunnel expansion caused by abrasive forces at the contact area, [13][14][15] which can be changed according to the direction of drilling and knee flexion angle.…”

“…There have been few studies that compare the tunnel geometry of TP techniques depending on whether they were used with the rigid system or the flexible system. [9][10][11] Furthermore, most of these studies evaluated only femoral tunnel length and the possibility of lateral structure damage using a cadaver. To our knowledge, there have been no in vivo studies that have used computed tomography (CT) to compare the crucial parameters of femoral tunnel geometry and aperture morphologic features associated with the differential postsurgical successes of the flexible and rigid systems when used with the TP technique.…”

The Sagittal Plane Angle and Tunnel-Related Complications in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique: An In Vivo Imaging Study

“…5,6 Conventional transtibial ACL reconstruction results in a graft more vertically oriented than the native ACL because of tibial constraints on femoral drilling. [7][8][9][10][11][12][13] Anatomic ACL reconstruction using an independent femoral tunnel restores graft obliquity that resembles the native ACL. 13 Thus the transportal technique, which creates independent femoral tunnels, has been a focus.…”