Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction Using the Modified Transtibial Technique Dhong Won Lee, M.D., and Jin Goo Kim, M.D., Ph.D.
Abstract: We present a technique for anterior cruciate ligament (ACL) reconstruction using hamstring tendon autograft with a modified transtibial technique. Our modified transtibial technique has the advantages of the conventional transtibial technique that is familiar to surgeons and that allows the press-fit fixing and enables us to make a relatively long femoral tunnel. To make the femoral tunnel at the anatomic position, the triangular, funnel-shaped bony trough was made to slip the eccentrically positioned guide pin into the anticipated anatomic center with a free-hand technique after marking the anatomic ACL footprint using a microfracture awl through the anteromedial portal. Gradual femoral reaming was performed with knee angle changes, which reduces the chances of posterior wall blowout, increases the femoral tunnel length, and avoids breakage of guide pin at the bending point. Our modified transtibial technique is anticipated to provide a more anatomic placement of the femoral tunnel during ACL reconstruction than the previous traditional transtibial techniques.
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hen performing arthroscopic anterior cruciate ligament (ACL) reconstruction, it is important to make tibial and femoral entrances in the anatomic location. Techniques such as modified transtibial technique, transanteromedial portal technique, and outside-in technique have been employed for anatomic single-bundle ACL reconstruction.1 Although the transtibial technique is familiar to most orthopaedic surgeons, it has the downside that the femoral tunnel position is dictated by the tibia bone tunnel, which makes anatomic femoral tunnel formation difficult.2,3 Further, several studies have been carried out to show that techniques such as anteromedial (AM) portal and outside-inmethods, where femoral tunnel positioning is independent of
From the Department of Orthopaedic Surgery, Armed Forces Daejeon Hospital (D.W.L.), Daejeon; and the Department of Orthopaedic Surgery, Konkuk University Medical Center (J.G.K.), Seoul, Republic of Korea. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received July 17, 2016; accepted September 12, 2016. Address correspondence to Jin Goo Kim, M.D., Ph.D., Professor of Orthopaedics, Chief of Sports Medical Center, 120-1, Neungdong-ro, Gwangjin-gu, Department of Orthopaedic Surgery, Konkuk University Medical Center, Seoul 143-729, Republic of Korea. E-mail:
[email protected] Ó 2016 by the Arthroscopy Association of North America 2212-6287/16680/$36.00 http://dx.doi.org/10.1016/j.eats.2016.09.028
the tibial tunnel, can produce an anatomically positioned femoral tunnel more easily than the transtibial technique.4 However, both techniques have their disadvantages. In the case of the AM portal technique, early rehabilitation tends to be stalled owing to short femoral tunnel length, risk of posterior wall damage, and relatively weak graft fixation, and thus, in the longterm, it leads to tunnel expansion and failure of ACL reconstruction.5 Although the outside-in method can produce a longer femoral tunnel, the steep slopes of the graft and tunnel result in complications such as graft damage and tunnel expansion.6 Furthermore, additional incision of the skin that is required in this process makes it esthetically unpleasing.6,7 The authors describe a modified transtibial technique using the advantages of the palliative transtibial technique that is familiar to surgeons and that allows the press-fit fixing technique that promotes swift soft tissue bone healing and enables us to make a relatively long Table 1. Tips and Pearls of Modified Transtibial Anterior Cruciate Ligament (ACL) Reconstruction 1. Initial marking of anatomic femoral ACL footprint via transanteromedial portal 2. Making a triangular, funnel-shaped bony trough 3. Free handling of femoral guide pin without offset guide 4. Gradual widening of femoral tunnel by changing the knee angle 5. Stronger fixation of the graft with dual fixation at tibia and femur
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Table 2. Pitfalls and Limitations 1. Possible widening of the intra-articular tibial tunnel aperture to posterolateral: We recommend using a reamer with a smaller shaft than head 2. Limited in young patients with wide open physis: We recommend the outside-in technique 3. Limited in failed previous transtibial technique: We recommend changing this technique to independent drilling methods 4. Occasional difficulty in approaching premade anatomic center with free-hand technique via tibial tunnel: We recommend changing this technique to independent drilling methods
femoral tunnel as well as create an anatomic femoral tunnel. Through the AM portal, a microfracture awl is placed just behind the bifurcate ridge to make the center of the anatomic femoral tunnel. The triangular, funnel-shaped bony trough is employed to slip the eccentrically positioned guide pin into the anticipated anatomic center with a free-hand technique, which is part of our modified transtibial technique. Gradual reaming of the femoral tunnel along with changing the knee angle to gain sufficient length and reduce posterior wall damage is another point of our technique. In addition, dual fixation methods for femoral and tibial tunnels could provide stronger fixation and promote early rehabilitation.
Surgical Technique This technical note describes the technique of anatomic single-bundle ACL reconstruction using a modified transtibial method (Video 1). The details are summarized in Tables 1 and 2. After detecting ACL rupture by arthroscopy, sartorius fascia from pes anserinus of the AM part of tibia is peeled and the semitendinous tendon is separated and
extracted. All reconstructions are performed with the transtibial technique with a quadruple hamstring tendon autograft. A microfracture awl is placed through the AM portal just behind the bifurcate ridge to make the center of the anatomic femoral tunnel (Fig 1). This center is deepened and widened to allow space for the guide pin through the tibial tunnel. Since the anatomic femoral tunnel is prepared by the AM portal viewing from the anterolateral (AL) portal, the transtibial guide pin tends to be located more to the anterior and distal position of anatomic center than anticipated. The triangular, funnel-shaped bone trough is employed via the AM portal to slip the eccentrically positioned guide pin into the anticipated anatomic center, which is part of modified transtibial technique (Fig 1). An ACL guide (Linvatec, Largo, FL) is used to make the tibial tunnel at an angle of 47.5 . The tunnel is positioned in the center of the remnant ACL stump. The guide pin is placed above the pes anserinus and in front of the medial collateral ligament (Fig 2). The tibial tunnel is made to have the same diameter as the graft using an expansion reamer. As soon as the reamer penetrates into the cortical bone of the tibial plateau, the expansion is ceased immediately to prevent further damage of residual fibers of the ACL. The guide pin is inserted into the tibial tunnel toward the preformed funnel-shaped bone trough with a free-hand technique (Fig 3). Generally, the guide pin is placed more distally and anteriorly than the anatomic center of the femoral attachment site, as seen by arthroscopy (Fig 3). When the knee joint is moved to an extension position during surgery, the guide pin will engage in a way to slip into its anatomic center from the tip of the bone trough (Fig 3). At this time, the guide pin is bent at the intraarticular aperture of the tibial tunnel (Fig 4). Since
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.
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reamer passes over the bending portion of the guide pin, the knee should be moved to extension (Fig 7). Once the reamer passes through this region, the knee joint is returned to a flexion position and the reamer is expanded to produce a femoral tunnel that has a similar diameter to that of the graft (Fig 7). The graft is channeled through the tibial tunnel and then through the femoral tunnel. After the graft passage, femoral fixation is achieved using the suspensory fixative device (Endobutton, Smith and Nephew, Andover, MA) and the bioecross pin (RIGIDFIX, Deupy Mitek, Raynham, MA). If the femoral tunnel length is below 30 mm, the Endobutton is used solely in a press-fit approach. Tibial fixation is performed with a bioabsorbable interference screw (BIORCI-HA, Smith and Nephew) and a cortical bone screw with washer. The diameter of the bioabsorbable screw is made to be the same size as the graft.
Discussion 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).
the femoral tunnel was made following the bent guide pin, the smallest diameter (6 mm on average) was used to start off the reaming just near the cortex (Fig 5). Then the new straight guide pin is inserted, redirecting in the same orifice (Fig 6). The reamer for a suspensory fixation system is used for the reaming until the far cortex, and the length of the femoral tunnel is measured. Upon femoral tunnel expansion, in order to gain sufficient length and reduce posterior wall damage, the knee joint is moved gradually from the extension to the flexion position (Fig 7). When the
The purpose of this technical note is to describe a single-bundle anatomic ACL reconstruction performed with the modified transtibial technique, especially for positioning the femoral tunnel to the anatomic footprint. Unlike previous reports that state that femoral tunnels produced from traditional transtibial techniques tend to lie more proximal and anterior than the anatomic position, our modified transtibial technique can produce a femoral tunnel that is only slightly distal and posterior to the anatomic position with the funnel-shaped bone trough.2,8,9 A recent study on 3-dimensional computed tomography evaluation after anatomic ACL reconstruction with the modified transtibial technique reported that the mean value of the femoral tunnels was between the AM and posterolateral bundle position compared with the mean
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 funnelshaped 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.
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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.
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.
value from multiple measurements of the anatomic ACL footprints in cadaveric knees from previous studies.8 Another important factor to consider when producing an anatomic femoral tunnel during the transtibial ACL reconstruction technique is the starting point of the tibial tunnel. Recent studies have attempted to achieve anatomic femoral attachment sites by altering the starting point of the tibia bone tunnel. Heming et al.10 put forward an argument that when the tibia bone tunnel is formed closer to the joint line, which helps to produce an anatomic femoral tunnel, this makes a shallow tibial tunnel and increases the possibility of frontal cortical bone breakage. Further, Chang et al.11 suggested that in order to produce an anatomic femoral tunnel using the transtibial technique, the starting point of the tibial tunnel should be 1.5 to 2 cm below the joint line, just anterior to the medial collateral ligament. However, our technique is distinct from theirs in that a guide pin was manually placed on the anatomic attachment site directly, whereas they used an offset guide to place the femoral tunnel in the direction toward which they predicted the tunnel should be. In our technique, we set the starting point of the tibial bone tunnel the same as in the method described by Arnold et al.9 to prevent short and shallow tunnel formation. Arnold et al.9 attempted to produce an anatomic femoral tunnel using this tibial starting point, but in their study, the guide pin was projected in too high and deep a position compared with recent studies without modifications.12-14 A funnel-shaped bone trough and alteration of the knee position to create extension and flexion to prevent slipping of the guide
pin into the nonanatomic position as described by Arnold et al.9 were implemented. This allowed the guide pin to be placed in the anatomic femoral tunnel position. Thus, we were able to gain a horizontal femoral tunnel with sufficient amount of tibial bone stock. The modified transtibial technique presented in this report has many advantages. First, it is a familiar technique used by many orthopaedic surgeons and is highly reproducible. Second, an anatomic femoral tunnel can be made by introducing a few simple techniques such as creating a funnel-shaped bone trough and altering the knee flexion angle during femoral tunnel construction. Finally, it is possible to create the femoral tunnel in an anatomic position through a relatively longer and deeper tibial tunnel. In summary, our modified transtibial technique is anticipated to provide a more anatomic placement of the femoral tunnel during ACL reconstruction than the previous traditional transtibial techniques and stable fixation using the advantages of the traditional transtibial techniques.
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.
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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.
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transportal and outside-in techniques in anterior cruciate ligament reconstruction: an in vivo 3-dimensional computed tomography analysis. Arthroscopy 2012;28: 1682-1694. Gadikota HR, Sim JA, Hosseini A, Gill TJ, Li G. The relationship between femoral tunnels created by the transtibial, anteromedial portal, and outside-in techniques and the anterior cruciate ligament footprint. Am J Sports Med 2012;40:882-888. Lee SR, Jang HW, Lee DW, Nam SW, Ha JK, Kim JG. Evaluation of femoral tunnel positioning using 3-dimensional computed tomography and radiographs after single bundle anterior cruciate ligament reconstruction with modified transtibial technique. Clin Orthop Surg 2013;5: 188-194. Arnold MP, Kooloos J, van Kampen A. Single-incision technique misses the anatomical femoral anterior cruciate ligament insertion: a cadaver study. Knee Surg Sports Traumatol Arthrosc 2001;9:194-199. Heming JF, Rand J, Steiner ME. Anatomical limitations of transtibial drilling in anterior cruciate ligament reconstruction. Am J Sports Med 2007;35:1708-1715. Chang CB, Yoo JH, Chung BJ, Seong SC, Kim TK. Oblique femoral tunnel placement can increase risks of short femoral tunnel and cross-pin protrusion in anterior cruciate ligament reconstruction. Am J Sports Med 2010;38: 1237-1245. Nha KW, Han JH, Kwon JH, Kang KW, Park HJ, Song JG. Anatomical single-bundle anterior cruciate ligament
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reconstruction using a freehand transtibial technique. Knee Surg Relat Res 2015;27:117-122. 13. Youm YS, Cho SD, Eo J, Lee KJ, Jung KH, Cha JR. 3D CT analysis of femoral and tibial tunnel positions after modified transtibial single bundle ACL reconstruction with varus and internal rotation of the tibia. Knee 2013;20:272-276.
14. Youm YS, Cho SD, Lee SH, Youn CH. Modified transtibial versus anteromedial portal technique in anatomic single-bundle anterior cruciate ligament reconstruction: comparison of femoral tunnel position and clinical results. Am J Sports Med 2014;42: 2941-2947.
