Fig. 29.1
(a) Partial rupture of the posterolateral (PL) bundle (white arrow). The anteromedial (AM) bundle (black arrow) of the ACL was well preserved although the remaining AM bundle is not completely intact. (b) AM bundle preserving ACL augmentation for the PL bundle rupture (white arrow, grafted tendon; black arrow, preserved AM bundle)
Fig. 29.2
(a) Partial rupture of the anteromedial (AM) bundle (black arrow). The posterolateral (PL) bundle (white arrow) of the ACL was preserved although the remaining PL bundle was not completely intact. (b) PL bundle preserving ACL augmentation for the AM bundle rupture (black arrow, grafted tendon; white arrow, preserved PL bundle)
29.2.2.1 Femoral Bone Tunnel
For femoral bone tunnel preparation, we regularly use the far-anteromedial portal technique, because this technique allows more flexibility in accurate anatomical positioning for femoral tunnel drilling than the transtibial technique. Excision of the femoral stump using a motorized shaver system is minimized. A delicate debridement and bone tunnel placement is important to minimize damage to the ACL remnant. It may be true that the main part of the femoral attachment of the ACL is on the resident’s ridge from the biomechanical point of view, and the remaining part (fan-like extension fibers) is attached to the posterior portion of the ridge. However, we think that the center of the femoral tunnel opening should not be on the resident’s ridge but should be placed just behind the resident’s ridge when using the hamstring tendon for ACL reconstruction [9]. This is because the graft is pulled and shifts to the anterodistal side of the femoral tunnel opening in knee extension and mild flexion position. The center of the bone tunnel opening is not the central point of the application of force.
In cases of PL bundle rupture, the central portion of the femoral tunnel is aimed at the clock position between 2 o’clock and 2:30 (left knee) or between 9:30 and 10 o’clock (right knee). At this position, approximately three-quarters of the femoral tunnel opening is occupied by the femoral attachment of the PL bundle and approximately one-quarter by the femoral attachment of the AM bundle. This is because we think that the remaining bundle is not intact and that the biomechanical function of the remaining bundle probably declines to some extent. In cases of AM bundle rupture, the central portion of the femoral tunnel was aimed at the clock position between 1:30 and 2 o’clock (left knee) or between 10 o’clock and 10:30 (right knee). In patients with a continuous thick ACL remnant between the intercondylar notch and the tibia after complete ACL rupture, the positions of the femoral bone tunnels is the same as used for standard anatomic single-bundle ACL reconstruction.
29.2.2.2 Tibial Bone Tunnel
In most cases, the tibial attachment of ACL remnant is normal. First, a longitudinal slit is made at the center of the ACL remnant through the anteromedial portal. The tip of the tibial drill guide, which is inserted through the anteromedial portal, is placed through the slit of the ACL remnant at an angle of 60–65° to the tibial plateau to allow visualization of the tip of the guide pin or Kirschner wire.
In cases of PL bundle rupture, the tip of the drill guide is positioned in the center of the tibial insertion of the whole ACL. In cases of AM bundle rupture and complete rupture, the tibial tunnel opening should be positioned as anterior as possible within the tibial footprint of the ACL. We recommend to check the position of the guide pin with the knee extended to see if the guide pin impinges on the roof of the intercondylar notch. When the position of the guide pin is satisfactory, the guide pin is advanced by a cannulated drill to create a tibial bone tunnel.
29.2.2.3 Graft Passage and Fixation
For cases such as the PL bundle rupture, if the graft passes above the ACL remnant, the positional relationship is anatomically incorrect. In such cases, pathologic impingement between the graft and the ACL remnant may occur. Therefore, in cases of PL bundle rupture and complete rupture, the graft should pass through the slit of the ACL remnant. As for the cases of AM bundle rupture, the graft should pass above the ACL remnant. The graft composites are introduced from the tibial tunnel to the femoral tunnel, and the proximal side of the graft is fixed to the lateral femoral cortex by flipping the endobutton. For graft fixation, we apply a tension force of 50 N to the distal endobutton tape connected to the graft and secure it with two staples at 30° of knee flexion.
29.3 Clinical Outcomes
29.3.1 Early History of ACL Augmentation
As detailed above, preserving the ACL remnant has great potential to contribute to knee function from several points of view. Therefore, in 1992, Ochi started performing ACL augmentation, when indicated, without sacrificing ACL remnant by using an autogenous hamstring tendon under arthroscopy. In 2000, Adachi et al. [11] reported that the proprioceptive function and joint stability of 40 patients who underwent arthroscopy-assisted ACL augmentation from 1992 to 1997 were superior to those of 40 patients who underwent standard single-bundle ACL reconstruction during the same period. However, in the early surgical procedure of ACL augmentation, the graft was passed through the over-the-top route for the femoral side. Therefore, the surgical technique needed two incisions at the medial aspect of the proximal tibia and also at the lateral femoral condyle. For this problem, Ochi started performing ACL augmentation with the one-incision technique using endobutton-CL and femoral bone tunnel and documented it as a report in 2006 [12]. The major indication for ACL augmentation was partial ACL rupture during the study period. In 2008, he started performing ACL augmentation even for patients with continuity of the ACL remnant between the femur and the tibia after complete ACL rupture. Anatomic central single-bundle ACL augmentation has been carried out for patients in this group.
29.3.2 Clinical Studies of ACL Augmentation
ACL augmentation has attracted much attention in the field of ACL reconstruction for this 10 years. Especially since 2006, a number of reports with regard to ACL augmentation has been published (Table 29.1) [13]. Several remnant-preserving techniques, including the remnant re-tensioning technique, selective AM or PL bundle reconstruction, and preservation of the ACL tibial remnant, have been described. To summarize the clinical results of ACL augmentation, we have reviewed the previous literature on ACL augmentation using a PubMed (1983–2014) and reported [13]. The review excluded case reports, literature review, animal studies, or current concepts. Table 29.1 [13] shows studies reporting arthroscopic remnant-preserving augmentation in ACL reconstruction. There are five different surgical techniques for ACL remnant preservation: (1) anatomic single-bundle ACL augmentation preserving ACL remnant for complete rupture, (2) anatomic double-bundle ACL augmentation preserving ACL remnant for complete rupture, (3) single-bundle ACL reconstruction with remnant-tensioning technique, (4) selective AM or PL bundle augmentation for partial rupture, and (5) standard ACL reconstruction plus tibial remnant sparing. The ACL remnant in (1) and (2) maintains a bridge between the tibia and the intercondylar notch.
Study | Study design | Patient numbera | Patient’s age (years)a | Time from injury to reconstruction (months)a | Mean follow-up (months)a |
|---|---|---|---|---|---|
Adachi and Ochi et al. (2000) [11] | Retrospective comparative study | 40 | 25.8 | 4.2 | 38 |
Ochi et al. (2006) [12] | Technical note | 17 | 31 | Not reported | Not reported |
Lee BI et al. (2006) [14] | Technical note | Not reported | Not reported | Not reported | Not reported |
Buda et al. (2006) [15] | Case series | 47 | 23.3 | 4.5 | (More than 60) |
Gohil et al. (2007) [16] | Randomized controlled trial | 22 | 30.5 | 2 | 12 |
Buda et al. (2008) [17] | Case series | 28 | 32.3 | Not reported | 27 |
Lee et al. (2008) [18] | Case series | 16 | 35.1 | 5.5 | 35.1 |
Ochi et al. (2009) [8] | Case series | 45 | 22 | 7.9 | 35 |
Yoon et al. (2009) [19] | Retrospective comparative study | 82 | 28 | 7 | 24 |
Ahn et al. (2009) [20] | Technical note | 65 | Not reported | Not reported | Not reported |
Kim et al. (2009) [21] | Technical note | 21 | Not reported | Not reported | 12 |
Ahn et al. (2010) [22] | Cohort study | 41 | 29.2 | 36.1 | 6.3 |
Sonnery-Cottet et al. (2010) [23] | Case series | 36 | 32 | 6.6 | 24 |
Serrano-Fernandez et al. (2010) [24] | Case series | 24 | 25 | 3 | 74 |
Ahn et al. (2011) [25] | Case series | 53 | 32.2 | 28.2 | 27.7 |
Jung et al. (2011) [26] | Retrospective comparative study | 76 | 32 | 2.5 | 31 |
Ochi et al. (2011) [10] | Technical note | Not reported | Not reported | Not reported | Not reported |
Pujol et al. (2012) [27] | Randomized controlled trial | 29 | 31.24 | 5.3 | (More than 12) |
Hong et al. (2012) [28] | Randomized controlled trial | 39 | 34 | 10.3 | 25.8 |
Ohsawa et al. (2012) [29] | Case series | 19 | (15–57) | 4.8 | 40.2 |
Yasuda et al. (2012) [30] | Case series | 44 | 29 | 4 | 16.6 |
Park et al. (2012) [31] | Retrospective comparative study | 55 | 30.4 | 7.0 | 34.1 |
Demirağ et al. (2012) [32] | Randomized controlled trial | 20 | 28 | 2.3 | 24.3 |
Sonnery-Cottet et al. (2012) [33] | Case series | 168 | 30 | 3 | 26 |
Cha et al. (2012) [34] | Retrospective comparative study | 100 | 31.9 | Not reported | Not reported |
Muneta et al. (2013) [35] | Cohort study | 88 | 22.1 | 6.7 | (More than 24) |
Kazusa and Ochi et al. (2013) [9] | Technical note | Not reported | Not reported | Not reported | Not reported |
Maestro et al. (2013) [36] | Retrospective comparative study | 39 | 28.1 | 1 | 31.7 |
Buda et al. (2013) [37] | Case series | 52 | 23.3 | 4.3 | (Up to 60) |
Abat et al. (2013) [38] | Case series | 28 | 30.4 | 2 | 37.3 |
Nakamae and Ochi et al. (2014) [39] | Retrospective comparative study | 73 | 26.6 | Not reported | 28.9 |
Zhang et al. (2014) [40] | Randomized controlled trial | 27 | 23.5 | 12.7 | 24.4 |
Lee et al. (2014) [41] | Retrospective comparative study | 16 | 30.6 | Not reported | 29.5 |
Ahn et al. (2014) [42] | Technical note | Not reported | Not reported | Not reported | Not reported |
Noh et al. (2014) [43] | Technical note | Not reported | Not reported | Not reported | Not reported |
Sonnery-Cottet et al. (2014) [44] | Technical note | Not reported | Not reported | Not reported | Not reported |
Muneta et al. (2014) [45] | Cohort study | 200 | Not reported | Not reported | Not reported |
Kim et al. (2014) [46] | Retrospective comparative study | 66 | 30 | 3 | 27 |
Taketomi et al. (2014) [47] | Technical note | 47 | 31
Related posts: Conservative Treatment of Pediatric ACL Injury
 Graft Rupture and Failure After ACL Reconstruction
 Anterolateral Ligament Reconstruction: Anatomy, Rationale, Technique, and Outcome
 ACL Graft Tensioning
 Anatomy of the ACL Insertions: Arthroscopic Identification of the Attachments
 Treatment of MCL Injury in Combined ACL/MCL Injury
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