The most important finding of the present study was that the anteromedial positioning of the femoral tunnel has a lower revision rate in ACL reconstruction.
It is not known where the best point is to the center the femoral tunnel [17,18,19].
Two similar studies published in 2013  and 2015  evaluated the mechanical functions of AM and posterolateral (PL) bands. Both studies found that the AM band presents greater anteroposterior and rotational stability. Considering therefore that the anteromedial region or band is the main stabilizer in both the anteroposterior and rotational planes, perhaps the ideal point for the center of the femoral tunnel is not exactly in the center of the LCA, as demonstrated in the previously mentioned studies [15, 19]. Another interesting recent discussion is related to the presence of two types of fibers in the ACL: direct and indirect . In 2012, a histological study  pointed to a microscopic four-layer structure in both the direct femoral and tibial insertion, demonstrating that the direct fibers are stronger and biomechanically more important, located in the lateral femoral intercondylar ridge. In addition, a recent study  demonstrated that no area of the ACL is actually isometric, but the region anterior to the center (between the AM and PL bands), i.e., the lateral femoral intercondylar crest, is the most isometric. Therefore, when approaching the center of the tunnel to lateral femoral intercondylar ridge and the anteromedial region, the center of the tunnel approaches a point that may function mechanically better than in the center of the native ACL, and this positioning is usually close to that obtained by transtibial reconstruction.
Studies that report more reruptures with the medial transportal technique compared to the transtibial technique are retrospective and have several limitations. The first important study that presented these results was published in 2013 . This was an evaluation of medical records of the Danish registry of ACL reconstructions, in which 9239 reconstructions performed by several surgeons in several hospitals between 2007 and 2010 were evaluated, a period considered by the study of popularization of the transportal technique, while the transtibial technique was already well-established. In addition, only the technique performed was evaluated, and not the exact placement of the tunnel, as there was no imaging examination to verify where the tunnels were actually placed. Another important study , with a similar methodology, evaluated the Swedish registry and found more reruptures with the medial transportal technique compared to the transtibial technique, but the authors subdivided the patients of the medial transportal group into anatomical transportal and reference transportal. For this division, the authors classified as anatomical those surgeries that the surgeons reported to have performed only anatomically, and classified as reference those who reported in the questionnaire to have used some anatomical parameters and the medial portal to choose the placement of the femoral tunnel. When comparing the transportal group with the transtibial group, they found the same need for revision in the groups. These studies [14, 15] are usually cited, but there are also other publications showing superior clinical results with the transportal technique, with less need for revision or without difference when comparing the medial transportal and transtibial techniques [5, 16]. It is important to note that we did not find any prospective, randomized, controlled series with homogeneous groups and patients operated by the same surgeon, that found more reruptures or better clinical outcome in the transtibial group.
In the present study, when comparing the techniques (transtibial x medial transportal x outside-in), the rerupture rate was 9.9% for the transtibial, 11.4% for the medial transportal and 7.2% for the outside-in technique, with no significant difference. However, comparing techniques is different from comparing tunnel placement. The present study compared the rerupture rate of the techniques but also compared the rerupture rate related to the placement sought by the same surgeon over 14 years. Two other recently published studies compared the rerupture rate related to the placement of the femoral tunnel. In the first , a rerupture rate of 7% was found in patients in whom the ACL was placed in the central (mid-bundle) position, and of 1.8% in those in the anteromedial bundle footprint position, with statistical significance. The second study  compared the anteromedial position obtained by the transtibial technique with the central position obtained by the medial transportal technique and found a rerupture rate of 5.9% of the cases in the anteromedial position versus 6.9% in the central region. In the present study, when comparing high AM (transtibial) x central x AM placement, there was a 9.9% rate of rerupture with high AM, 9.2% with central, and 4.5% with AM. Although the P-value of 0.371 indicates no significant difference, we believe this is a type 2 statistical error, i.e., with a larger sample, the p-value would tend to decrease until at some point it reaches statistical significance. When comparing the AM placement with the others, the AM placement had a 4.5% rerupture rate, while the others had 9.2%, also with no statistical significance, but perhaps with the same type 2 error, corroborating with the data in the literature presented above and with the greater importance of the anteromedial region of the ACL [20, 21].
Despite evaluating the placement of the tunnels with the different techniques, this placement was not documented with imaging tests. In addition, the techniques changed over time, and thus older techniques had more time for the occurrence of new ruptures. Another factor that deserves to be mentioned is that the transportal technique has a smaller sample than the other techniques, and thus few cases of rerupture associated with this technique considerably change the rate in this group.
Knowing that the best results are obtained with the anteromedial positioning of the femoral tunnel in the ACL reconstruction. The choice of technique by the surgeon in daily practice is made easier, and the risk of revisions decreases.