Lee et al. [25] reported a useful TT technique for SB reconstruction. In creating the tibial tunnel, the knee was flexed to 90°, and the entry point was set 4–5 cm distal to the joint line, 2–3 cm posteromedial to the tibial tuberosity, 1 cm superior to the attachment site of the pes anserinus, and just anterior to the medial collateral ligament (MCL). A guide pin was then inserted at an angle of 60° to the tibial plateau with the use of a tibial drill guide (Acufex, Andover, Massachusetts) aimed midway between the ACL footprints of the anteromedial and posterolateral bundles. A 10-mm tibial tunnel was drilled. In creating the femoral tunnel, a 7-mm offset femoral drill guide (Acufex) was aimed at the lateral bifurcate ridge on the medial wall of the lateral femoral condyle with the knee flexed to 90° and an anterior drawer force, a varus force, and an external rotation force applied to the proximal aspect of the tibia while externally rotating the guide. The anterior drawer force enables more inferior positioning of the femoral tunnel; the varus force, posterior positioning of the femoral tunnel; and the external rotation force and external rotation of the guide, both inferior positioning and posterior positioning of the femoral tunnel. A femoral tunnel guide pin was then inserted through the guide, and a 10-mm femoral tunnel was drilled through the tibial tunnel.

Lee et al. [25] radiologically and clinically evaluated this TT technique in comparison with the AMP technique. Two- and three-dimensional images of CT scans showed that there were no significant differences concerning not only the graft obliquity in the coronal and sagittal planes but also the femoral tunnel position, as evaluated with the use of the quadrant method, between the two groups (Fig. 22.3a). This femoral tunnel position was identical to the anatomic point (Fig. 22.3b), which was shown in the previous anatomical study [26]. In addition, there were no significant differences in the clinical results between the two groups in terms of manual laxity tests, arthrometric analysis, and several clinical scores.

Yasuda et al. [47] reported the first practical procedure to reconstruct the mid-substance fibers of the AM and PL bundles using the TT technique. To create the tibial tunnels for the PL and AM bundles, they developed an arthroscopy-assisted guidewire navigation device (Guidewire Navigator III, Smith and Nephew Endoscopy Japan, Tokyo, Japan). The surgeon holds the tibia at 90° of knee flexion, keeping the femur horizontal, and placed a tip of this device at the center of each bundle footprint on the tibia (Fig. 22.4). Then, after they aimed the femoral indicator in the tip at the center of each footprint on the femur, the extra-articularly located wire sleeve was fixed on the anteromedial aspect of the tibia. Thus, the location and direction of the wire sleeve were automatically determined on the tibia, depending on the direction of the intra-articular navigator tip. A Kirschner wire of 2 mm in diameter is drilled through the sleeve in the tibia. The first tunnel is made for the PL bundle reconstruction with a cannulated drill which corresponds to the measured diameter of the prepared substitute (commonly 6 mm). Then, the second tunnel is drilled for the AM bundle reconstruction in the same manner (commonly 7 mm). In the patients successfully operated with this TT technique, the tibial tunnel angles of the posterolateral bundle averaged 41° in the anteroposterior view and 35° in the lateral view [21]. The tibial tunnel angles of the anteromedial bundle averaged 16° in the anteroposterior view and 41° in the lateral view.

Concerning the femoral tunnel creation for the AM bundle reconstruction, our anatomical study [18] demonstrated that the averaged center of the direct attachment of the AM bundle mid-substance fibers was located on the cylindrical surface of the femoral intercondylar notch at “10:37” (or “1:23”) o’clock orientation in the distal view and at 5.0 mm from the proximal outlet of the intercondylar notch (POIN) in the lateral view (Fig. 22.5). To insert a guidewire into this point, we developed the following quantitative method: through the tibial tunnel, we introduced a 5-mm offset guide (Twisted Offset Guide, Smith and Nephew Endoscopy Inc., Tokyo, Japan) into the joint cavity and set the hook-shaped tip of this guide at the POIN at 90–100° of knee flexion. Keeping the hook at this point, we aimed a guidewire at the “1:30” or “10:30” o’clock orientation, an eighth of a circle, in the arthroscopic visual field. Thus, in actual operations, a surgeon inserted a Kirschner wire to the femur using this quantitative technique. Our clinical study [18] to evaluate the accuracy of this technique showed that the average location of the AM tunnel actually created in the ACL reconstruction was at “10:41” (or “1:19”) o’clock orientation and at 5.0 mm from the POIN (Fig. 22.5). There was no significant difference between the averaged center location of the native AMB attachment and that of the actually created tunnels. The results suggested that the above-described quantitative technique is useful to insert a guidewire into the averaged center of the native AM bundle attachment.

Regarding the femoral tunnel creation for the PL bundle reconstruction, we reported a geometric method to estimate the averaged center of the direct attachment of the PL bundle mid-substance in the original procedure [47]. In an arthroscopic visual field, we could draw an imaginary vertical line through the contact point between the lateral femoral condyle and the tibial plateau at 90° of knee flexion. This line and the long axis of the ACL remnant were crossed at the point 5–8 mm anterior to the edge of the joint cartilage (Fig. 22.6). The averaged center of the normal attachment of the PL bundle was located approximately at this crossing point. In actual operation, a surgeon observed the lateral condyle with a 30° arthroscope inserted through the medial infrapatellar portal, keeping the femur horizontal at 90° of knee flexion. The surgeon held a guidewire manually and aimed it at the crossing point on the femur through the tibial tunnel. To adjust the guidewire at this point, a surgeon must utilize the physiological knee laxity. Namely, the “leg-hanging” position is commonly necessary, and the “figure 4” position is needed in some cases. Thus, two anatomical femoral tunnels were created on the lateral condyle (Fig. 22.7a).

To evaluate this TT technique, several radiological, biomechanical, and clinical studies have been conducted. Inoue et al. [16] radiologically evaluated the accuracy of this TT technique (Fig. 22.7b) and reported that it is useful for clinical use. Biomechanically, the tunnel positions created with this TT technique could restore the knee functions close to that of the normal knee [23, 49]. The clinical results of this anatomic DB reconstruction procedure are significantly better that the conventional SB reconstruction [22, 48]. In addition, recently, this TT technique has been successfully performed in remnant tissue-preserving anatomic DB reconstruction.

The review has showed that, although the conventional TT techniques had obvious disadvantages, many “modified” TT techniques have recently been reported to improve them. This chapter has explained that the anatomic tunnel creation can be successfully performed with the modern TT techniques in both SB and DB ACL reconstructions, although there are some controversies concerning the anatomic femoral point on the femoral condyle. Then, we should recognize that, not only in the AMP and OI techniques but also in the TT technique, a surgeon must use some additional procedures to precisely or safely insert a guidewire at the anatomical point on the femur. In the future studies to compare the TT technique with the other two techniques, researchers should evaluate not only the accuracy of the tunnel location and direction but also all merits and demerits of the additional procedures.

At this time, the TT, AMP, and OI techniques have their own set of advantages and disadvantages [38]. Concerning the TT technique, the advantages include less surgical pain and morbidity, better cosmesis with no lateral incision, reduced surgical time, parallel bone tunnels, technically familiar and less demanding, lower risk of revision, and beneficial to place the graft penetrating the remnant ACL tissue [24, 51]. The disadvantages involved elliptical tunnel outlet on the lateral condyle, inability to freely position femoral tunnel, fluid leakage through the tibial tunnel, and an increased cost due to special devices [38]. On the other hand, the AMP technique has the following advantages and disadvantages [38]. The advantages include independent placement of femoral and tibial tunnels, ease of approach to the femoral targeted point, tunnel placement independent of tunnel guides, and allowing parallel placement of interference screws. The previous studies pointed out the following disadvantages: technically demanding (difficulty visualizing instruments due to limited visibility in hyperflexion, inability to maintain aimer in hyperflexed knee, difficulty passing instruments due to portal tightening in hyperflexion, difficulty seating endoscopic aimer), challenges with graft fixation device passage, short or bicortical sockets which may limit fixation options, potential damage to common peroneal nerve, posterior-wall blowout and potential damage to posterior articular cartilage, iatrogenic damage to cartilage of medial femoral condyle, low portal placement which may injure anterior horn of medial meniscus, higher graft failure rates, and increased risk of revision. Concerning the OI technique, the following advantages and disadvantages have been described in the previous reports [38]. The advantages include less risk of bone tunnel divergence, ease of approach to the targeted point, avoidance of posterior-wall blowout, and ease of use for revision ACL procedures. The disadvantages involve greater surgical morbidity with lateral incision, greater abrasion of the graft at the intra-articular edges of the tunnel, increased operative time, worse cosmesis, and increased cost due to special devices.