Aperture Fixation in Arthroscopic Anterior Cruciate Ligament Double-Bundle Reconstruction

The native anterior cruciate ligament (ACL) consists of 2 bundles, which have distinct biomechanical yet synergistic functions with respect to anterior tibial translation and combined rotatory loads. Traditionally, most ACL reconstruction techniques have primarily addressed the restoration of the anteromedial bundle, and less consideration was given to the posterolateral bundle. Recently, various ACL double-bundle reconstruction techniques have been described. With most of these techniques, however, an indirect extra-anatomic fixation far from the articular surface was performed. Because extra-anatomic fixation techniques, rather than aperture fixation techniques, are associated with graft tunnel motion, windshield wiper action, and suture stretch-out, concerns may arise regarding delayed biological incorporation, tunnel enlargement, and secondary rotational and anterior instability. We, therefore, present a novel arthroscopic technique that reapproximates the footprints of native ACL with the use of double-strand semitendinosus and gracilis autografts for reconstruction of the anteromedial and posterolateral bundles, respectively. A separate femoral and tibial tunnel is drilled for each double-strand autograft. The femoral tunnel for the anteromedial bundle is drilled primarily through a transtibial technique, and the femoral tunnel for the posterolateral bundle is drilled via an accessory anteromedial portal with the use of a 4-mm offset drill guide in the anteroinferior aspect of the femoral tunnel for the anteromedial bundle. Bioabsorbable interference screws are used in aperture fixation for anatomic fixation of each bundle. This technique attempts to reproduce closely the native ligament and its biomechanical function.     

Three-Dimensional Reconstruction Computed Tomography Evaluation of Tunnel Location during Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of Transtibial and 2-Incision Tibial Tunnel-Independent Techniques

Background

Anatomic tunnel positioning is important in anterior cruciate ligament (ACL) reconstructive surgery. Recent studies have suggested the limitations of a traditional transtibial technique to place the ACL graft within the anatomic tunnel position of the ACL on the femur. The purpose of this study is to determine if the 2-incision tibial tunnel-independent technique can place femoral tunnel to native ACL center when compared with the transtibial technique, as the placement with the tibial tunnel-independent technique is unconstrained by tibial tunnel.

Methods

In sixty-nine patients, single-bundle ACL reconstruction with preservation of remnant bundle using hamstring tendon autograft was performed. Femoral tunnel locations were measured with quadrant methods on the medial to lateral view of the lateral femoral condyle. Tibial tunnel locations were measured in the anatomical coordinates axis on the top view of the proximal tibia. These measurements were compared with reference data on anatomical tunnel position.

Results

With the quadrant method, the femoral tunnel centers of the transtibial technique and tibial tunnel-independent technique were located. The mean (± standard deviation) was 36.49% ± 7.65% and 24.71% ± 4.90%, respectively, from the over-the-top, along the notch roof (parallel to the Blumensaat line); and at 7.71% ± 7.25% and 27.08% ± 7.05%, from the notch roof (perpendicular to the Blumensaat line). The tibial tunnel centers of the transtibial technique and tibial tunnel-independent technique were located at 39.83% ± 8.20% and 36.32% ± 8.10%, respectively, of the anterior to posterior tibial plateau depth; and at 49.13% ± 4.02% and 47.75% ± 4.04%, of the medial to lateral tibial plateau width. There was no statistical difference between the two techniques in tibial tunnel position. The tibial tunnel-independent technique used in this study placed femoral tunnel closer to the anatomical ACL anteromedial bundle center. In contrast, the transtibial technique placed the femoral tunnel more shallow and higher from the anatomical position, resulting in more vertical grafts.

Conclusions

After single-bundle ACL reconstruction, three-dimensional computed tomography showed that the tibial tunnel-independent technique allows for the placement of the graft closer to the anatomical femoral tunnel position when compared with the traditional transtibial technique.     

经胫骨隧道与前内侧入路建立前交叉韧带股骨隧道的比较研究

目的 比较关节镜下前交叉韧带(ACL)重建术中经胫骨隧道与髌下前内侧入路建立股骨隧道的长度和角度。 方法回顾性分析2000年11月至2009年11月收治的102例ACL重建手术患者资料,其中50例采用经胫骨隧道建立股骨隧道（经胫骨隧道组）：男39例,女11例;年龄15～49岁,平均（27.9±7.6）岁。52例采用经前内侧入路建立股骨隧道（前内侧入路组）：男33例,女19例;年龄15～56岁,平均(30.5±10.7)岁。术中记录股骨隧道长度,术后行膝关节前后位及侧位X线片检查,测量股骨隧道在冠状面与内、外髁连线及矢状面与股骨干轴线的夹角,并进行统计学分析。 结果 经胫骨隧道组股骨隧道的平均长度[（50.9±5.0）mm]长于前内侧入路组[(37.8±4. 7)mm],差异有统计学意义(t=15.083,P=0. 000);经胫骨隧道组冠状面股骨隧道角度(68.6°±7.0°)、矢状面股骨隧道角度(45.1°±8.1°)均大于前内侧入路组(49.8°±7.7°)、33.7°±9.7°),差异均有统计学意义(t=12. 874,P=0. 000;t =5. 877,P=0. 000)。 结论关节镜下ACL重建术中,采用前内侧入路制备的股骨隧道长度短、角度小。     

Oblique femoral tunnel or oblique graft? A modified anteromedial portal technique to obtain vertical femoral tunnel and oblique graft in anatomic anterior cruciate ligament reconstruction

In anterior cruciate ligament (ACL) reconstruction, transtibial drilling of the femoral tunnel has been criticized for its vertical and less anatomical tunnel, which accompanied rotational instability of knee. Many authors recommend anteromedial (AM) portal drilling technique, which creates more oblique and anatomic femoral tunnel. However, recent researches show that oblique tunnel is related to risks of too short femoral tunnel, blowout of back wall, and posterolateral structures injury. Is oblique femoral tunnel really essential for anatomic reconstruction? We introduce a modified AM technique, which abandons the oblique tunnel and provides vertical femoral tunnel and oblique graft with anatomic starting point. The fundamental of the new technique is that oblique graft but not oblique tunnel is essential for rotational stability of knee. Thus, it avoids the risks and preserves anatomic reproduction of ACL.     

Anteromedial Portal Technique for Creating the Anterior Cruciate Ligament Femoral Tunnel

There has been a renewed focus on anterior cruciate ligament (ACL) insertional anatomy and its biomechanics. It has been postulated that traditional single-bundle transtibial reconstructions have placed grafts in a less anatomic location relative to the true ACL insertion site. In traditional transtibial techniques, the femoral tunnel is predetermined by the position of the tibial tunnel. It is our belief that achieving the most anatomic position for the graft requires the femoral and tibial tunnels to be drilled independently. Use of the anteromedial portal technique provides us with more flexibility in accurately placing the femoral tunnel in the true ACL insertion site as compared with the transtibial technique. Advantages include anatomic tunnel placement, easy preservation of any remaining ACL fibers when performing ACL augmentation procedures, and flexibility in performing either single- or double-bundle reconstructions in primary or revision settings. This technique is not limited by the choice of graft or fixation and offers the advantage of true parallel screw placement through the same portal as that used for tunnel drilling in the case of interference fixation.     

Intraoperative Qualitätskontrolle bei der Bohrkanalplatzierung zum vorderen Kreuzbandersatz

The reconstruction of a ruptured anterior cruciate ligament (ACL) is a frequently performed operation, however technically demanding with a revision rate of approximately 10%. The correct placement of bone tunnels in femur and tibia is the most important variable to achieve a successful outcome. A distinct knowledge of the anatomic insertion sites is crucial. The ideal location for the femoral bone tunnel is achieved when a 1-2 mm posterior wall is left to the over-the-top position and when the entry to the bone tunnel is at 10 o'clock (right knees) or 14 o'clock (left knees) in the frontal plane. The femoral bone tunnel can be drilled through the tibial bone tunnel (transtibial technique) or through an anteromedial arthroscopic portal. According to recent studies the use of an anteromedial portal helps to reduce the risk of misplacement of the bone tunnel. The center of the tibial bone tunnel should be located on an imaginary line between medial border of the anterior horn of the lateral meniscus and the medial tibial spine. The position of the tibial guide wire has to be far enough posterior to avoid impingement of the graft with the roof of the intercondylar notch. Measures for quality control include the intraoperative use of an image intensifier (fluoroscopy), instrumented laxity measurements and a postoperative radiograph in 2 planes. The use of computer assisted surgery cannot routinely be recommended at present.     

Double bundle revision of a malplaced single bundle vertical ACL reconstruction: ACL revision surgery using a two femoral tunnel technique

Background  Several factors influence the outcome after ACL reconstruction. One of the most important factors influencing the resulting knee kinematics and subjective instability is femoral tunnel placement. Revision can be necessary if the femoral tunnel is drilled transtibial in the roof of femoral notch (mismatch). Hypothesis  Double bundle reconstruction using two femoral tunnels and one tibial tunnel technique can be used in revision of a primary vertical ACL reconstruction. Study design  Case series (level of evidence III). Methods  ACL revision was performed in five patients complaining instability after primary transtibial ACL reconstruction. Clinical examination, X-ray and CT analysis were performed to evaluate objective knee laxity, tunnel placement and widening. In all patients a technique using two femoral tunnels in a two medial portal technique and one tibial tunnel was used. Patients were reevaluated at a follow up of 24 months. Results  Preoperatively, pivot shift tests were 2+ in three and 1+ in the remaining two patients. Lachman test was found to be positive in all patients (4 patients, 2+ firm endpoint; 1 patient, 2+ soft endpoint). X-rays showed a femoral tunnel position at 11.30 (1 patient) and 12.00 o’clock (4 patients). In one patient significant tibial tunnel enlargement was to be found. At a follow up of 24 months, KT 1000 was <2 mm side to side difference and the pivot shift test was negative in all patients. Conclusion  Revision of a primary vertical ACL reconstruction can be safely performed using a double bundle reconstruction with two femoral tunnels in a two medial portal technique and one tibial tunnel technique. The femoral tunnel need to be located in the anatomic origin of the AM and PL bundle. Clinical relevance  Femoral tunnel placement in the notch of the intercondylar notch should be avoided. In these cases without significant tunnel enlargement, a primary double bundle revision with two femoral and one tibial tunnel can be performed.     

Drilling the Femoral Tunnel During ACL Reconstruction: Transtibial Versus Anteromedial Portal Techniques

Incorrect bone tunnel position, particularly on the femoral side, is a frequent cause of failed anterior cruciate ligament reconstruction. Several studies have reported that drilling the femoral tunnel through the anteromedial portal allows a more anatomical placement on the lateral femoral condyle and higher knee stability than does transtibial reconstruction.In the current study, the femoral tunnel was drilled with transtibial (n=6) and anteromedial (n=6) portal techniques in 12 cadaveric knees. With appropriate landmarks inserted into bone tunnels, the direction and length of the tunnels were determined on anteroposterior and lateral radiographs. Knee stability was evaluated with a KT1000 arthrometer (MEDmetric Corporation, San Diego, California) and pivot shift test, comparing the pre- and postoperative values of both techniques. Finally, all knees were dissected to enhance vision of the insertion of the reconstructed ligament. The anteromedial portal technique led to better placement of the femoral tunnel in the coronal and sagittal planes, with higher knee stability according to the pivot shift test but not the KT1000 arthrometer.Anatomical and clinical results reported in the literature on transtibial and anteromedial portal techniques are controversial, but most of studies report better results with the anteromedial portal technique, especially regarding rotational stability. The current cadaveric study showed that the anteromedial portal technique provided better tunnel placement on the lateral femoral condyle in the coronal and sagittal planes, with an improvement in the rotational stability of the knee.     

Editorial Commentary: Anteromedial Portal Drilling of the ACL Femoral Socket Avoids Transtibial Constraint Results in Anatomic Reconstruction and Superior Outcomes

Femoral and tibial tunnel locations for ACL grafts should be predicated on anatomy. Regarding femoral ACL socket or tunnel creation, multiple techniques have been debated. Network meta-analysis shows that the anteromedial portal (AMP) technique results in better anteroposterior and rotational stability than does the “standard” constrained, transtibial technique based on side-to-side differences in laxity and pivot-shift tests, as well as IKDC objective scores. The AMP provides a direct shot at the anatomic ACL origin on the femur. It avoids the osseous constraint of the reamer that hampers transtibial approaches. It avoids the extra incision required by the outside-in technique and the accompanying graft obliquity. Despite the need for knee hyperflexion and the potential for shorter femoral sockets, the AMP technique should be easily reproducible for an accomplished ACL surgeon to reproduce the patient’s anatomy.     

Technical note: Anterior cruciate ligament reconstruction in the presence of an intramedullary femoral nail using anteromedial drilling

AIM To describe an approach to anterior cruciate ligament(ACL) reconstruction using autologous hamstring by drilling via the anteromedial portal in the presence of an intramedullary(IM) femoral nail.METHODS Once preoperative imagining has characterized the proposed location of the femoral tunnel preparations are made to remove all of the hardware(locking bolts and IM nail). A diagnostic arthroscopy is performed in the usual fashion addressing all intra-articular pathology. The ACL remnant and lateral wall soft tissues are removed from the intercondylar, to provide adequate visualization of the ACL footprint. Femoral tunnel placement is performed using a transportal ACL guide with desired offset and the knee flexed to 2.09 rad. The Beath pin is placed through the guide starting at the ACL's anatomic footprint using arthroscopic visualization and/or fluoroscopic guidance. If resistance is met while placing the Beath pin, the arthroscopy should be discontinued and the obstructing hardware should be removed under fluoroscopic guidance. When the Beath pin is successfully placed through the lateral femur, it is overdrilled with a 4.5 mm Endobutton drill. If the Endobutton drill is obstructed, the obstructing hardware should be removed under fluoroscopic guidance. In this case, the obstruction is more likely during Endobutton drilling due to its larger diameter and increased rigidity compared to the Beath pin. The femoral tunnel is then drilled using a best approximation of the graft's outer diameter. We recommend at least 7 mm diameter to minimize the risk of graft failure. Autologous hamstring grafts are generally between 6.8 and 8.6 mm in diameter. After reaming, the knee is flexed to 1.57 rad, the arthroscope placed through the anteromedial portal to confirm the femoral tunnel position, referencing the posterior wall and lateral cortex. For a quadrupled hamstring graft, the gracilis and semitendinosus tendons are then harvested in the standard fashion. The tendons are whip stitched, quadrupled and shaped to match the diameter of the prepared femoral tunnel. If the diameter of the patient's autologous hamstring graft is insufficient to fill the prepared femoral tunnel, the autograft may be supplemented with an allograft. The remainder of the reconstruction is performed according to surgeon preference. RESULTS The presence of retained hardware presents a challenge for surgeons treating patients with knee instability. In cruciate ligament reconstruction, distal femoral and proximal tibial implants hardware may confound tunnel placement, making removal of hardware necessary, unless techniques are adopted to allow for anatomic placement of the graft. CONCLUSION This report demonstrates how the femoral tunnel can be created using the anteromedial portal instead of a transtibial approach for reconstruction of the ACL.     

Comparisons of tunnel-graft angle and tunnel length and position between transtibial and transportal techniques in anterior cruciate ligament reconstruction

Purpose

Our aim was to evaluate tunnel-graft angle, tunnel length and position and change in graft length between transtibial (30 patients) and anteromedial (30 patients) portal techniques using 3D knee models after anterior cruciate ligament (ACL) reconstruction.

Methods

The 3D angle between femoral or tibial tunnels and graft at 0° and 90° flexion were compared between groups. We measured tunnel lengths and positions and evaluated the change in graft length from 0° to 90° flexion.

Results

The 3D angle at the femoral tunnel with graft showed a significant difference between groups at 0° flexion (p?=?0.01) but not at 90° flexion (p?=?0.12). The 3D angle of the tibial tunnel showed no significant differences between groups. Femoral tunnel length in the transtibial group was significantly longer than in the transportal group (40.7 vs 34.7 mm,), but tibial tunnel length was not. The relative height of the lateral femoral condyle was significantly lower in the transportal than the transtibial group (24.1 % vs 34.4 %). No significant differences were found between groups in terms of tibial tunnel position. The change in graft length also showed no significant difference between groups.

Conclusion

Even though the transportal technique in ACL reconstruction can place the femoral tunnel in a better anatomical position than the transtibial technique, it has risks of a short femoral tunnel and acute angle at the femoral tunnel. Moreover, there was also no difference in the change of the graft length between groups.     

Anatomic assessment of femoral tunnel by transtibial drilling technique in double-bundle anterior cruciate liga- ment reconstruction： an in vivo study

Objective： To evaluate the anatomy of femoral tunnels created by simulated transtibial technique in double-bundle anterior cruciate ligament （ACL） reconstruction. Methods： Two tibial tunnels, anteromedial （AM） and posterolateral （PL）, were drilled 45° and 55° to tibial plateau respectively. On the femoral side, the AM and PL tunnels were drilled through anteriomedial portal. After the four tun- nels were established, the shaft of a reamer was introduced into the joint through tibial tunnel and reached against the lateral wall of intercondylar notch. The position that the reamer shaft can reach was marked and recorded. Results： Neither femoral AM nor PL tunnel opening can be fully or partially reached by the reamer shaft through the tibial AM tunnel in all cases. The evaluation through the tibial PL tunnel showed that only in 8 of 50 cases （16%） the femoral AM tunnel opening and in 4 cases （8%） the PL opening can be fully reached. On the other hand, in 12 cases （24%） the femoral AM tunnel opening and in 10 cases （20%） the PL opening can be partially reached by the shafts through the tibial PL tunnel. Conclusion： The result strongly suggests that transtibial technique is not well competent for femoral tun- nel drilling in anatomic double-bundle ACL reconstruction as we have hypothesized.     

前交叉韧带解剖双束重建中股骨隧道建立路径的比较研究

目的前瞻性研究在关节镜下前交叉韧带（ACL）解剖双束重建术中,采用经胫骨隧道与经前内人路定位建立股骨隧道的可行性与准确性。方法在连续30例ACL患者的解剖双束重建术中,首先分别以45°、55°角钻取胫骨隧道,关节内出口分别在ACL胫骨解剖附丽区印记的前内和后外,保留1～2mm间隔骨桥;关节外入口分别位于胫骨结节内侧和内侧副韧带前缘的前方,间隔以两枚Washer不重叠为准,分别用于前内侧束和后外侧束的移植重建。然后分别经两胫骨隧道,将两根球头空心钻的钻杆自胫骨隧道插入关节内,观察两钻头杆能否到达理想的股骨隧道,录像记录并进行统计学分析。结果在本组30例患者中,经胫骨前内侧束隧道插入的钻头杆,在股骨侧的指向全部偏高、偏前,无一例能完全或部分到达股骨侧前内侧或后外侧束隧道口;而经胫骨后外侧束隧道的钻头杆,经屈或伸膝调整角度后,5例（16．7％）可完全到达、8例（26．7％）可部分到达股骨的前内侧束隧道口;有2例（6．7％）可完全到达、6例（20．0％）部分到达股骨的后外侧束隧道口。而经前内入路屈膝120°后,28例（93．3％）定位可达到理想位置。结论在ACL解剖双束移植重建中,经胫骨隧道定位钻取股骨隧道的方法不可靠、准确性差、变异较大、可重复性差;而经前内入路方法可调节性强、准确性好、股骨隧道短、不受胫骨隧道方向、角度和直径的影响、简便易行、重复性好;但应注意要在较大的屈膝角度下定位钻取。     

No-Tunnel Anterior Cruciate Ligament Reconstruction: The Transtibial All-Inside Technique

The purpose of this technical note is to describe the transtibial all-inside anterior cruciate ligament (ACL) reconstruction technique. This technique combines the advantages of previously described but technically demanding all-inside ACL reconstruction techniques with the ease and familiarity of transtibial guide pin placement. The all-inside technique uses bone sockets as opposed to bone tunnels in both the femur and the tibia and represents a “no-tunnel” technique. When performed with allograft tissue, the method requires only arthroscopic portals and percutaneous guide pin passage. In such cases, this represents a “no-incision” ACL reconstruction. The technique requires the use of a Dual Retrocutter (Arthrex, Naples, FL). This cannulated drill is placed via the anteromedial arthroscopic portal and threads onto a transtibial, percutaneous, reverse-threaded guide pin. Because the drill is assembled arthroscopically (within the joint), a skin incision is not required. The Dual Retrocutter is capable of retrograde and antegrade drilling. Thus, a single Dual Retrocutter achieves transtibial drilling of both tibial and femoral bone sockets. The transtibial all-inside technique may be performed with the use of any ACL graft option. Graft diameter should equal socket diameter. To prevent the graft from “bottoming-out” during tensioning and fixation, graft length must be less than the sum of combined femoral plus tibial socket lengths plus ACL intra-articular distance. During the learning curve, surgeons may choose to wait until the sockets have been prepared, so that graft length need not be estimated. If the graft is prepared before arthroscopic surgery is performed, a 79-mm graft length could be recommended as ideal. To prepare for graft passage, both femoral and tibial graft passing suture loops must be brought out the anteromedial arthroscopic portal without soft tissue interposition between or within the loops. To prepare for graft fixation, a nitinol wire must be brought into the joint via the transtibial, percutaneous guide pin tract for the purpose of guiding the introduction of a cannulated Retroscrewdriver. All of these goals may be accomplished in a single pass. The graft is fixed with femoral and tibial Retroscrews. Backup fixation is optional and may be achieved by tying sutures over small, percutaneously placed cortical buttons. Advantages of this technique may result from “anatomic” graft fixation at the levels of the femoral and tibial joint lines and from retrograde screw fixation, which may eliminate interference screw divergence and increase graft tension when the retrograde screw is advanced. Additionally, because this technique minimizes skin incisions and eliminates open bone tunnels, patients may experience decreased pain, more rapid return to function, and improved cosmesis.     

Trantibial anterior cruciate ligament double bundle reconstruction technique: two tibial bundle in one tibial tunnel

The anterior cruciate ligament (ACL) consists of two functional bundles that behave independently throughout the range of knee motion. Many two-bundle reconstruction techniques have been introduced to restore the function of the two bundles of the ACL. Generally, two femoral and two tibial tunnels are made during the surgery for a two-bundle ACL reconstruction. However, the procedure is technically demanding and time consuming. This paper describes one-tibial-two-femoral ACL double bundle reconstruction technique with a sextuple-stranded hamstring autograft. The anteromedial femoral tunnel is made using transtibial drilling technique and posterolateral femoral tunnel is made using outside-in technique. The two bundles in a single tibial tunnel are separated using biodegradable interference screw. Stable and adequate femoral fixation of the two bundles with a transtibial fixation and bioabsorbable screw can be obtained. This technique is relatively simple, and replicates the anatomy and differential behavior of the two native bundles of ACL more effectively.     

Femoral tunnel placement in anterior cruciate ligament reconstruction: rationale of the two incision technique

Endoscopic anterior cruciate ligament (ACL) reconstruction can be performed through one-incision or two-incision technique. The current one-incision endoscopic ACL single bundle reconstruction techniques attempt to perform an isometric repair placing the graft along the roof of the intercondylar notch, anterior and superior to the native ACL insertion. However the ACL isometry is a theoretical condition, and has not stood up to detailed testing and investigation. Moreover this type of reconstruction results in a vertically oriented non-anatomic graft, which is able to control anterior tibial translation but not the rotational component of the instability. Femoral tunnel obliquity has a great effect on rotational stability. To improve the obliquity of graft, an anatomical ACL reconstruction should be attempt. Anatomical insertion of ACL on the femur lies very low in the notch, spreading between 11 and 9–8 o'clock position and the center lies lower than at 11 o'clock position. Femoral aiming devices through the tibial tunnel aim at an isometric placement, and they do not aim at an anatomic position of the graft. Also, a placement of tunnel in a position of 11 o'clock is unable to restore rotational stability. The two-incision technique, with the possibility to position femoral tunnel independently by tibial tunnel, allows us to place femoral tunnel entrance in a position of 10 'clock that can most accurately reproduce the anatomic behaviour of the ACL and can potentially improve the response of the graft to rotatory loads. This positioning results in a more oblique graft placement, avoiding problem related to PCL impingement during knee flexion. Further studies are required to understand if this kind of reconstruction can ameliorate proprioception as well as clinical outcome at a long-term follow-up.     

3D CT evaluation of femoral and tibial tunnels in anatomic double bundle anterior cruciate ligament reconstruction

BackgroundAn anatomical double bundle ACL reconstruction replicates the anatomy of native ACL as the tunnels are made to simulate the anatomy of ACL with AM and PL bundle foot prints. The goal of anatomic ACL reconstruction is to tailor the procedure to each patient’s anatomic, biomechanical and functional demands to provide the best possible outcome. The shift from single bundle to double bundle technique and also from transtibial to transportal method has been to provide near anatomic tunnel positions.PurposeTo determine the position of femoral and tibial tunnels prepared by double bundle ACL reconstruction using three dimensional Computed tomography.Study designA prospective case series involving forty patients with ACL tear who underwent transportal double bundle ACL reconstruction.MethodComputed tomography scans were performed on forty knees that had undergone double bundle anterior cruciate ligament reconstruction. Three-dimensional computed tomography reconstruction models of the knee joint were prepared and aligned into an anatomical coordinate axis system for femur and tibia respectively. Tibial tunnel centres were measured in the anterior-to-posterior and medial-to-lateral directions on the top view of tibial plateau and femoral tunnel centres were measured in posterior to anterior and proximal-to-distal directions with anatomic coordinate axis method. These measurements were compared with published reference data.ResultsAnalysing the Femoral tunnel, the mean posterior-to-anterior distances for anteromedial and posterolateral tunnel centre position were 46.8% ± 7.4% and 34.5% ± 5.0% of the posterior-to-anterior height of the medial wall and the mean proximal-to-distal distances for the anteromedial and posterolateral tunnel centre position were 24.1% ± 7.1% and 61.6% ± 4.8%. On the tibial side, the mean anterior-to-posterior distances for the anteromedial and posterolateral tunnel centre position were 28.8% ± 4.3% and 46.2% ± 3.6% of the anterior-to posterior depth of the tibia measured from the anterior border and the mean medial-to-lateral distances for the anteromedial and posterolateral tunnel centre position were 46.5% ± 2.9% and 50.6% ± 2.8% of the medial-to-lateral width of the tibia measured from the medial border. There is high Inter-observer and Intra-observer reliability (Intra-class correlation coefficient).Discussion and conclusionFemoral AM tunnel was positioned significantly anterior and nearly proximal whereas the femoral PL tunnel was positioned significantly anterior and nearly distal with respect to the anatomic site. Location of tibial AM tunnel was nearly posterior and nearly medial whereas the location of tibial PL tunnel was very similar to the anatomic site Evaluation of location of tunnels through the anatomic co-ordinate axes method on 3D CT models is a reliable and reproducible method. This method would help the surgeons to aim for anatomic placement of the tunnels. It also shows that there is scope for improvement of femoral tunnel in double bundle ACL reconstruction through transportal technique.     

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.     

Reduction of femoral interference screw divergence during endoscopic anterior cruciate ligament reconstruction.

One of the complications of endoscopic anterior cruciate ligament (ACL) reconstruction is femoral interference screw divergence, usually occurring when the femoral screw insertion is different than the portal used for reaming the femoral tunnel. A new technique using a StraightShot graft passer (DePuy Orthopaedic Technology, Tracy, CA) allows the safe passage of a 7 mm M. Kurosaka Advantage cannulated femoral interference screw (DePuy) through the tibial tunnel with the patella tendon graft fully in position. This study compares femoral interference screw divergence in bone-patellar tendon-bone ACL reconstruction using two different screw insertion portals: the accessory anteromedial patella portal and the tibial tunnel portal (StraightShot technique). A radiographic analysis of 81 consecutive endoscopic ACL reconstructions was performed. The total divergence of each femoral screw was measured on both anteroposterior and lateral radiographs and then combined. Group I had the 7-mm femoral screw inserted through the accessory anteromedial patella portal; group II had the femoral screw inserted directly through the tibial tunnel. Group I showed more than 10 degrees of divergence in 50% of the cases, compared with only 4% percent in group II. The average divergence dropped from 11.3 degrees in group I to 1.2 degrees in group II. Femoral interference screw divergence can be virtually eliminated by inserting the femoral screw directly through the tibial tunnel using the StraightShot technique.