Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction Using the Modified Transtibial Technique  Dhong Won Lee, M.D., Jin Goo Kim, M.D., Ph.D.  Arthroscopy Techniques  Volume 6, Issue 1, Pages e227-e232 (February 2017) DOI: 10.1016/j.eats.2016.09.028 Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 1 (A) As viewed through the anterolateral portal, centering of the anatomic anterior cruciate ligament footprint is performed using a microfracture awl via the anteromedial portal in the left knee. The dotted line represents the lateral bifurcate ridge. (B) The triangular, funnel-shaped bone trough is made in the femoral anterior cruciate ligament footprint in the left knee as viewed from the anteromedial portal. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 2 The starting point of the tibial tunnel (black arrow) in the left knee is the point of interaction between the lateral to anterior margin of the medial collateral ligament (white line) and upper margin of pes anserinus (black line). Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 3 (A) The guide pin tends to be placed more distally and anteriorly than the anatomic center of the femoral footprint as viewed from the anterolateral portal in the left knee that is kept in flexion. (B) When the left knee joint is moved to an extension position, the guide pin engages in a way to slip into the anatomic center of the femoral footprint from the tip of the funnel-shaped bone trough via the tibial tunnel. (C) After engaging the guide pin in the femoral anatomic center, the left knee is returned to flexion. The black arrow represents the triangular, funnel-shaped bone trough. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 4 The transtibial guide pin is bent at the intra-articular aperture of the tibial tunnel after engaging it in the femoral anatomic center in the right knee as viewed from the anterolateral portal. The black circle presents the bending point at the intra-articular aperture of the tibial tunnel. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 5 The smallest diameter (6 mm on average) is used to start off the reaming just near the cortex via the tibial tunnel in the right knee as viewed from the anterolateral portal. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 6 The new straight guide pin is inserted redirecting in the same orifice after 6 mm of reaming just near the cortex in the right knee as viewed from the anterolateral portal. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 7 (A) Upon femoral tunnel expansion in the right knee, when the reamer passes over the bending portion of the transtibial guide pin, the knee should be moved to extension as viewed from the anterolateral portal. (B) Once the reamer passes through the bending portion of the transtibial guide pin as viewed from the anterolateral portal, the right knee joint is returned to a flexion position in order to gain sufficient length and reduce posterior wall damage and the reamer is expanded to produce a femoral tunnel that has a similar diameter as that of the graft. The black circle represents the entrance of the femoral tunnel of traditional transtibial technique, and the white circle and quadrangle represent the entrance of the femoral tunnel of the modified transtibial technique. Arthroscopy Techniques 2017 6, e227-e232DOI: (10.1016/j.eats.2016.09.028) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions