**6. The move toward anatomy**

Several surgeons, who early recognized the need to further improve the outcome of ACL reconstruction, moved towards a more anatomic way to reconstruct the ACL. This was mostly based on the drawbacks of the transtibial technique

Contemporary Anterior Cruciate Ligament Reconstruction 207

femoral tunnel through an AM portal allows obtaining tunnel aperture which overlaps with the native ACL footprint, while drilling through the tibial tunnel hardly covers part of the AM footprint (Abebe et al., 2009). Modifying the tibial tunnel orientation to overcome this issue has been proposed (Chhabra et al., 2004; Heming et al., 2007; Kopf et al., 2010; Miller et al., 2010). When drilling a more horizontal tunnel, and starting more medial it becomes possible to target the native ACL footprint. However, the resulting tunnel becomes very short, with a quite oval intra-articular tunnel aperture, putting the medial tibial plateau at risk for fracture, rising concerns for tibial graft fixation, and compromising graft stability at the tunnel aperture. Nevertheless, transportal drilling technique has pearls and pitfalls which have been described in the literature (Basdekis et al., 2008; Harner et al., 2008; Lubowitz, 2009; Zantop et al., 2008).

The location of the instrumental anteromedial (AM) portal, also called accessory AM- or far medial portal is critical (Fig. 9). The best way to locate it is to use a spinal needle, keeping the scope through the anterolateral (AL) portal in order to optimize its placement under direct vision. The needle must sit above the anterior segment of the medial meniscus, far enough from the medial femoral condyle not to damage the cartilage when using endoscopic drills. Single fluted endoscopic drills reduce the risk for cartilage damages. If the portal is close to the patellar tendon the drill will be oriented at sharp angle with regard to the lateral wall of the intercondylar notch resulting in an oval femoral tunnel aperture. If the portal is more medial, the orientation of the drill will result in a more circular aperture.

Fig. 9. Portal location for transportal drilling technique. Anterolateral portal (AL) is high in the soft spot above the fat pad. Proximal anteromedial portal (PAM) is located at the junction betwwen the patella and the medial femoral condyle. Distal anteromedial (DAM)

During drilling, the knee must be bent at least at 110 degree of flexion in order to avoid blowing up the posterior wall of the lateral femoral condyle (Fig. 10). The more the knee is

portal is located above the anterior segment of the medial meniscus

**7.1 Portals** 

**7.2 Drilling** 


Fig. 8. Position of the femoral guide wire inserted eiher transtibial or transportal in cadaver. All the three illustrations are from the same right knee. A: 1 transtibial guide wire inserted at 90 degree of flexion, 2 transportal guide wire inserted at 110 degree of knee flexion. B: intra-articular visualization of the guide wires from the medial side (TT transtibial, AM transportal). C: The medial femoral condyle has been removed. The TT guide wire is located in the roof of the intercondylar notch out of the ACL foot print. The AM guide wire is right in the center of the AMB attachment sire (pink). The PL footprint is colored in green.

#### **7. Transportal technique**

Drilling the femoral tunnel through an anteromedial (AM) portal has been described early on (Clancy, 1985; Cain & Clancy, 2002; Deehan & Pinczewski, 2002). These authors recognized the best and easiest way to reach the femoral ACL footprint was to drill through an AM portal. Transportal technique allows positioning the femoral tunnel lower in the notch, where the ACL is attached, with a more horizontal tunnel, offering in addition to the tibial translation control a better rotational control compared to the transtibial technique (Alentorn-Geli et al., 2009; Bedi et al., 2010; Bedi et al., 2011; Bottoni, 2008; Dargel et al., 2009; Gavriilidis et al., 2008; Loh et al.,2003; Rue et al., 2008; Sohn & Garrett, 2009; Zantop et al., 2008). Also, drilling the femoral tunnel through an AM portal allows obtaining tunnel aperture which overlaps with the native ACL footprint, while drilling through the tibial tunnel hardly covers part of the AM footprint (Abebe et al., 2009). Modifying the tibial tunnel orientation to overcome this issue has been proposed (Chhabra et al., 2004; Heming et al., 2007; Kopf et al., 2010; Miller et al., 2010). When drilling a more horizontal tunnel, and starting more medial it becomes possible to target the native ACL footprint. However, the resulting tunnel becomes very short, with a quite oval intra-articular tunnel aperture, putting the medial tibial plateau at risk for fracture, rising concerns for tibial graft fixation, and compromising graft stability at the tunnel aperture. Nevertheless, transportal drilling technique has pearls and pitfalls which have been described in the literature (Basdekis et al., 2008; Harner et al., 2008; Lubowitz, 2009; Zantop et al., 2008).
