Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction With Anatomic Aimers

Graft positioning is a key issue in anterior cruciate ligament (ACL) reconstruction and even more sensitive in double-bundle reconstruction, where 2 tunnels have to be drilled within the ACL footprints at both the femoral and tibial insertion sites. Specific ancillary instruments have been developed to facilitate the positioning of the 4 sockets necessary when performing anatomic double-bundle ACL reconstruction. This technical note describes the rationale and the step-by-step method of using the specific aimers developed for this purpose. However, a prerequisite for successful double-bundle ACL reconstruction is a good knowledge of ACL footprint anatomy.     

Hybrid Anterior Cruciate Ligament Reconstruction: Introduction of a New Technique for Anatomic Anterior Cruciate Ligament Reconstruction

Recently, anatomic or double-bundle reconstruction of the anterior cruciate ligament (ACL) has been presented in an effort to more accurately restore the native anatomy. These techniques create 2 tunnels in both the femur and tibia to reproduce the bundles of the ACL. However, the increased number of tunnels, particularly on the femoral side, has raised some concerns among authors and surgeons. We describe a technique to reconstruct the 2 distinct bundles of the ACL by using a single femoral tunnel and 2 tibial tunnels, the “hybrid” ACL reconstruction. The femoral tunnel is drilled through an anteromedial arthroscopy portal, which allows placement in a more anatomic position. Fixation in the femur is achieved with a novel device that separates a soft-tissue graft into 2 independently functioning bundles. Once fixed in the femur, the anteromedial and posterolateral bundles of the graft are passed through respective tunnels at the anatomic footprint on the tibia. These bundles are independently tensioned, which creates a reconconstruction that is similar to the native ACL. The technique presented provides surgeons with an alternative to other double-bundle techniques involving 4 tunnels.     

Anterior Cruciate Ligament Double-Bundle Reconstruction With Hamstring Tendon Autografts

The anterior cruciate ligament (ACL) surgical technique via a 5-strand hamstring tendon autograft is designed with a conventional single-bundle reconstruction that has shown favorable results and an additional posterolateral (PL) bundle reconstruction. The conventional single-tunnel technique is performed for the tibial tunnel, and the double-tunnel technique is performed for the femoral tunnel. The anteromedial (AM) femoral tunnel is prepared with 1 mm of the posterior femoral cortex being left over the top at the 11- to 1-o’clock position. The PL femoral tunnel is prepared with the outside-in technique by use of a 4.5-mm cannulated reamer. The AM bundle is fixed with a rigid fixation system on the femoral side, and the PL bundle is fixed to tie with the miniplate from the outside femur. A double-bundle reconstruction with 5-strand hamstring autografts, in conjunction with a conventional AM bundle and an additional PL bundle, seems to be a very effective method for the treatment of ACL instabilities. Although the long-term clinical outcome of the procedure is yet to be determined, complications including graft impingement, limitation in range of motion, and residual instability have not been observed to date in the first 38 patients who have undergone our technique.     

前交叉韧带的生物力学研究

目的研究前交叉韧带（ACL）在维持膝关节前后稳定和旋转稳定中的作用。方法标本取自新鲜尸体的5只膝关节，分别在ACL完整和切断的情况下对标本施加股四头肌力和腔股关节作用力，采用应变计测量技术和计算机图形处理技术对受载膝关节位移和转角进行测量和图像重建。结果在负载作用下，ACL切断与否对膝关节内、外旋角度的影响很小，但对腔骨前后位移的影响很大。结论ACL是维持膝关节前后稳定的重要结构。     

A Comparison of the Fixation Strengths Provided by Different Intraosseous Tendon Lengths during Anterior Cruciate Ligament Reconstruction: A Biomechanical Study in a Porcine Tibial Model

Background

The purpose of this study was to determine the tibial fixation strength provided by different intraosseous soft tissue graft lengths within the tibial tunnel.

Methods

Porcine tibial bones and digital flexor tendons were used for testing. Bone mineral densities of proximal tibial medial condyles were measured, and two-strand tendon bundles of 8 mm diameter were used. An intraosseous graft length of 2 cm was used in group 1 (n = 10), and a graft length of 4 cm was used in group 2 (n = 10). Tunnels were 4 cm in length and 8 mm in diameter. Tibial fixation was performed using a suture tied around a screw post with a washer and an additionally inserted 7 × 20 mm bioabsorbable screw. After applying preconditioning loading of 10 cycles, 1,000 cycles between 70-220 N were applied at a frequency of 1 Hz. Graft slippage and total graft movement were recorded. Ultimate tensile strength was measured by pull-out testing at an Instron crosshead speed of 1,000 mm/min.

Results

No significant intergroup difference was found for total graft movement after cyclic loading (slippage in group 1, 1.2 mm and group 2, 1.2 mm, respectively, p = 0.917; and total graft movement in group 1, 3.3 mm and group 2, 2.7 mm, respectively, p = 0.199). However, mean ultimate tensile strength in group 2 was significantly higher than that in group 1 (group 1, 649.9 N; group 2, 938 N; p = 0.008).

Conclusions

In a porcine model, ultimate tensile strength was greater for a 4 cm long intraosseous flexor tendon in the tibial tunnel. However, no intergroup difference in graft slippage or total graft movement was observed. The results show that a 2 cm intraosseous graft length in the tibial tunnel is safe and has sufficient strength (> 450 N) for adequate rehabilitation after anterior cruciate ligament reconstruction.     

Twenty-Year Experience of a Double-Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a four-strand semitendinosus tendon was started in our department in July 1994. The motivation for starting the procedure was that the EndoButton with an inside-out procedure instrument became available in Japan. A review article of our DB ACL reconstruction procedure was summarized for the twentieth anniversary of the surgical procedure. Initial tension setting of the two grafts was changed in the first 8 years to achieve better stability during DB ACL reconstruction. A randomized clinical trial (RCT) was started in July 2002 to clarify superiority of the DB procedure to single-bundle (SB) reconstruction under the concept of anatomic reconstruction. Several anatomic studies were performed to describe normal ACL anatomy, which is essential for realizing anatomic reconstruction. A remnant-preserving technique would be an additional option for our DB procedure to improve reconstruction outcomes. Thus, a new remnant-preserving DB procedure was started in 2012. The reproducibility of the new procedure was investigated using three-dimensional computed tomography images. More complex procedures were performed using a transtibial technique and EndoButtons. Initial tension balancing between the two grafts was important for a better outcome. Superiority of knee stability after the DB compared to that after the SB procedure was clarified by the RCT. However, no patient consensus has been reached on any subjective advantage to the DB procedure. Studies of normal ACL anatomy have left questions unresolved regarding where the two tunnels should be created for direct and indirect insertions based on normal anatomy. A new remnant-preserving DB ACL procedure has been practiced. The procedure was more reproducible with respect to creating the femoral tunnel. DB ACL reconstruction using a semitendinosus tendon is an attractive option when pursuing a better outcome for patients.     

Injury to the Anterior Tibial Artery during Bicortical Tibial Drilling in Anterior Cruciate Ligament Reconstruction

Many complications have been reported during or after anterior cruciate ligament (ACL) reconstruction, including infection, bleeding, tibial tunnel widening, arthrofibrosis, and graft failure. However, arterial injury has been rarely reported. This paper reports a case of an anterior tibial arterial injury during bicortical tibial drilling in arthroscopic ACL reconstruction, associated with an asymptomatic occlusion of the popliteal artery. The patient had a vague pain which led to delayed diagnosis of compartment syndrome and delayed treatment with fasciotomy. All surgeons should be aware of these rare but critical complications because the results may be disastrous like muscle necrosis as in this case.