X线影像导航系统辅助关节镜下前交叉韧带重建术

目的 探讨X线影像导航系统辅助关节镜下前交叉韧带重建手术的可行性和隧道位置的精确性。方法 2005年12月至2006年2月共行X线影像导航系统辅助前交叉韧带重建手术30例（导航手术组）,同期使用传统关节镜手术技术重建前交叉韧带40例（传统手术组）,术前进行股骨、胫骨隧道理想位置的设计。术中C臂透视机获得正侧位影像后传输入计算机系统形成虚拟工作界面。膝关节周围分别固定股骨、胫骨追踪器。手术工具装配追踪器。经过注册及校准后,导航系统通过捕获追踪器发射的信号实时跟踪手术工具的位置方向,并叠加在工作界面上,达到导航的目的。本文对导航手术组进行总结,术后进行胫骨隧道位置测量,并与传统手术组进行比较。结果术后测量,导航手术组胫骨隧道位置平均值45．90％（41．00％～49．80％,标准差2．36％）,传统手术组胫骨隧道位置在41．05％（范围25．00％～54．00％,标准差6．01％）,两组结果差异有统计学意义（P〈0．05）。同时导航组的平均手术时间较传统组延长20min,透视次数为4次。术后短期随访（1-3个月）,两组膝关节稳定性无明显差异。结论 X线影像导航系统辅助关节镜下前交叉韧带重建手术是安全、可行的,通过术前规划,可以使股骨、胫骨隧道位置更精确。     

A New Technique for Femoral and Tibial Tunnel Bone Grafting Using the OATS Harvesters in Revision Anterior Cruciate Ligament Reconstruction

Revision anterior cruciate ligament (ACL) reconstruction is becoming more frequent, especially in specialized centers, because of the large numbers of primary ACL procedures performed. In 2-stage revisions, bone grafting of the tunnels may be undertaken if the primary position was inaccurate or if osteolysis has caused widening of the tunnels. This will allow the desired placement of the new tunnels without the risk of loss of structural integrity. It is technically difficult to deliver and impact bone graft into the femoral tunnel with the standard surgical and arthroscopic instruments. We describe a new technique for femoral and tibial tunnel impaction grafting in 2-stage ACL revisions, using the OATS grafting instruments (Osteochondral Autologous Transfer System; Arthrex, Naples, FL). The appropriately sized OATS harvester is chosen 1 mm larger than the tunnel size and is used to harvest bone graft from the iliac crest through a percutaneous approach. This provides a cylindrical graft, which is delivered to the femoral tunnel through the arthroscopic portal. The inside punch of the harvester is tapped and this allows delivery of the graft in a controlled manner and its impaction into the tunnel. The same is repeated for the tibial tunnel while providing support for the proximal end of the tunnel.     

Intraoperative 3-Dimensional Imaging–Based Navigation-Assisted Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

In anatomic double-bundle anterior cruciate ligament (ACL) reconstruction, it is more technically demanding, even for experienced surgeons, to place 2 femoral tunnels within the ACL attachment than to place 2 tibial tunnels. We describe a technique using a three-dimensional (3-D) fluoroscopy–based navigation system to place 2 femoral tunnels accurately. After a reference frame is rigidly attached to the femur, an intraoperative image of the distal femur is obtained. The image is transferred to a navigation system and reconstructed into a 3-D image. During the placement of guidewires for the femoral tunnels through an accessory medial portal, a femoral guide with a tracker feeds back to the surgeons the direction of the guidewire on the 3-D femur bone surface image in real-time. The femoral guide is placed at the center of the footprint with the aid of visual guidance of the navigation and an arthroscopic view. The flexion angle of the knee is then adjusted to prevent posterior blowout on the computer screen during insertion of the guidewire. The length of the femoral tunnel can also be estimated before overdrilling the guidewire. This technology allows surgeons to place 2 femoral tunnels precisely without any complication during anatomic double-bundle ACL reconstruction.     

Precision of ACL tunnel placement using traditional and robotic techniques.

The objective of this study was to examine the precision of ACL tunnel placement using: (1) CASPAR (orto MAQUET GmbH Co. KG)--an active robotic system, and (2) four orthopedic surgeons with various levels of experience (between 100 and 3,500 ACL reconstructions). The robotic system and each surgeon drilled tunnels for ACL reconstruction in 10 plastic knees (total n = 50) that included a reference cube in the medial aspect of the proximal tibia and distal femur. For the robotic system, the placement of each tunnel was planned preoperatively using custom software and CT data for each femur and tibia. The robotic system then drilled the tunnels in the femur and tibia based on the preoperative plan. For the surgeons, tunnel placement was accomplished using their preferred technique, which was based on the one-incision arthroscopic technique. The distribution of intra-articular points on the tibia was contained within a sphere of radius 2.0 mm (robot system), 2.1 mm (Fellow 1), 2.4 mm (Fellow 2), 3.4 mm (Experienced Surgeon 1), or 2.0 mm (Experienced Surgeon 2). On the femur, no significant differences in the distribution of intra-articular points could be demonstrated between the robotic system (2.1 mm), Fellow 1 (4.5 mm), Fellow 2 (4.1 mm), Experienced Surgeon 1 (2.3 mm), and Experienced Surgeon 2 (3.0 mm). The direction of the tunnels drilled in the femur and tibia was different with the robotic and traditional techniques. However, the robotic system had the most consistent tunnel directions, while the surgeons' tunnels were more dispersed. Variation in surgeon precision of tunnel placement for ACL reconstruction is greater on the femur than the tibia, and this can be correlated with experience. Our data also suggest that the robotic system has the same precision as the most experienced surgeons.     

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.     

Endoscopic anterior cruciate ligament reconstruction using a computer-assisted fluoroscopic navigation system

Background During anterior cruciate ligament (ACL) reconstruction, placement of the reconstructed ligament affects the clinical results. To accomplish accurate and reproducible placement of the tibial bone tunnel, we employed a fluoroscopic navigation system for endoscopic ACL reconstruction. In this study, preciseness of the tibial tunnel placement was evaluated, and the advantages and disadvantages of this navigation system for endoscopic ACL reconstruction are discussed. Methods Altogether, 16 knees of 16 patients who had undergone ACL reconstruction using this system (navi group) were evaluated regarding the positioning of the tibial tunnel against Blumensaat's line using X-p and the route of the graft by magnetic resonance imaging (MRI). Another 16 knees of 16 patients who underwent endoscopic ACL reconstruction without the navigation system were the controls (control group). Results At the 1-year follow-up, maximally extended lateral knee X-p revealed that the anterior edge of the tibial tunnel and Blumensaat's line were almost aligned and that roof impingement was avoided; the T2-weighted MR images showed that the graft was placed close to and parallel to the intercondylar roof in all the knees of the navi group. The ratio of the distance between Blumensaat's line and the anterior edge of the tibial tunnel at the level of the tibial plateau to the anteroposterior width in fully extended true lateral radiographs was 2.7% ± 3.4% in the navi group and 8.4% ± 7.4% in the control group. Conclusions The computer-assisted fluoroscopic navigation system improves accuracy and decreases dispersion of the tibial tunnel placement against Blumensaat's line in single-bundle ACL reconstruction. This innovative device renders the reconstruction procedure more reliable, eliminating the problem of skeletal variation among patients. However, the function of this navigation system for femoral tunnel placement is insufficient at present. Further refinement of the system is necessary, and the method of application requires improvement.     

前交叉韧带重建术后骨道增宽的临床研究

目的分析前交叉韧带（ACL）重建术后骨道增宽的发生率、增宽程度、骨道形状、相关因素及其与临床效果的关系。方法回顾性研究应用胭绳肌腱重建ACL手术后骨道的变化,通过X线片测量ACL重建术后的骨道直径。对51例患者行ACL重建手术,其中男性30例,女性21例。所有患者均获随访,平均随访时间16个月。主要研究及观察指标：患者性别、年龄、身高等因素,移植物的固定方式,随访时的关节活动度、膝关节稳定性检查（KT2000）及肌力恢复情况,以及股骨和胫骨的骨道直径、骨道位置和角度等。数据分析采用统计学卡方检验及相关性分析。结果前交叉韧带重建术后的骨道增宽率股骨85％-94％,胫骨65％;增宽程度股骨51％-53％,胫骨40％～44％。胫骨骨道增宽的形态以O型（冠位片）及V型（矢位片）最常见。骨道增宽与年龄、身高及体重指数相关。股骨骨道位置偏前会引起股骨骨道的增宽,股骨骨道角或胫骨骨道角越小,则股骨骨道越容易增宽。结论以腘绳肌腱为移植物重建前交叉韧带手术,术后骨道增宽的发生率与程度,股骨骨道较胫骨骨道明显。骨道增宽与患者年龄、身高以及骨道定位相关,其中股骨和胫骨骨道的位置及角度是引起术后骨道增宽的主要因素之一。骨道增宽与KT2000结果和术后肌力恢复情况相关。     

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.     

Anatomical analysis of the anterior cruciate ligament femoral and tibial footprints

Background The current trend in anterior cruciate ligament (ACL) reconstruction has shifted to anatomical double-bundle (DB) reconstruction, which reproduces both the anteromedial bundle (AMB) and the posterolateral bundle (PLB) of the ACL. Navigation systems have also been recently introduced to orthopedic surgical procedures, including ACL reconstruction. In DB-ACL reconstruction, the femoral and tibial tunnel positions are very important, but a representation of the ACL footprint under an arthroscopic view has not been established even though navigation systems have been introduced. The purpose of this study was to evaluate the anatomical footprints of both the AMB and the PLB using the representation method for application to arthroscopic DB-ACL reconstruction using a navigation system, and to evaluate the validity of the currently determined footprint position compared with other representation methods. Methods Thirty-six cadaveric knees were used for an anatomical evaluation of footprints of the AMB and PLB. On the tibial side, the ACL footprints were evaluated using an original method. On the femoral side, the ACL footprints were evaluated using Watanabe’s method and three other methods: (1) the quadrant method, (2) Mochizuki’s method, and (3) Takahashi’s method. Results The central points of the ACL footprints were represented almost constantly. The present data is in accordance with previous measurement data. Conclusion This study showed that the anatomical data of the ACL femoral and tibial footprints determined with Watanabe’s method at the femoral side and our original method at the tibial side were both applicable to arthroscopic surgery with a navigation system.     

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.     

Medial portal technique for single-bundle anatomical Anterior Cruciate Ligament (ACL) reconstruction

The aim of the paper is to describe the medial portal technique for anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Placement of an ACL graft within the anatomical femoral and tibial attachment sites is critical to the success and clinical outcome of ACL reconstruction. Non-anatomical ACL graft placement is the most common technical error leading to recurrent instability following ACL reconstruction. ACL reconstruction has commonly been performed using a transtibial tunnel technique in which the ACL femoral tunnel is drilled through a tibial tunnel positioned in the posterior half of the native ACL tibial attachment site. ACL reconstruction performed using a transtibial tunnel technique often results in a vertical ACL graft, which may fail to control the combined motions of anterior tibial translation and internal tibial rotation which occur during the pivot-shift phenomenon. The inability of a vertically oriented ACL graft to control these combined motions may result in the patient experiencing continued symptoms of instability due to the pivot-shift phenomenon. The medial portal technique in which the ACL femoral tunnel is drilled through an anteromedial or accessory anteromedial portal allows consistent anatomical ACL tunnel placement. This paper describes the advantages of the medial portal technique, indications for the technique, patient positioning, proper portal placement, anatomical femoral and tibial tunnel placement, graft tensioning and fixation.     

Radiological landmarks for placement of the tunnels in single-bundle reconstruction of the anterior cruciate ligament

There is little evidence examining the relationship between anatomical landmarks, radiological placement of the tunnels and long-term clinical outcomes following anterior cruciate ligament (ACL) reconstruction. The aim of this study was to investigate the reproducibility of intra-operative landmarks for placement of the tunnels in single-bundle reconstruction of the ACL using four-strand hamstring tendon autografts. Isolated reconstruction of the ACL was performed in 200 patients, who were followed prospectively for seven years with use of the International Knee Documentation Committee forms and radiographs. Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnel was a mean of 86% (sd 5) along Blumensaat's line and the tibial tunnel was 48% (sd 5) along the tibial plateau. Taking 0% as the medial and 100% as the lateral extent, the tibial tunnel was 46% (sd 3) across the tibial plateau and the mean inclination of the graft in the coronal plane was 19 degrees (sd 5.5). The use of intra-operative landmarks resulted in reproducible placement of the tunnels and an excellent clinical outcome seven years after operation. Vertical inclination was associated with increased rotational instability and degenerative radiological changes, while rupture of the graft was associated with posterior placement of the tibial tunnel. If the osseous tunnels are correctly placed, single-bundle reconstruction of the ACL adequately controls both anteroposterior and rotational instability.     

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。     

Three-Portal Technique for Anterior Cruciate Ligament Reconstruction: Use of a Central Medial Portal

Standard endoscopic reconstruction of the anterior cruciate ligament (ACL) is performed with the use of 2 arthroscopic portals. The surgical error most commonly associated with ACL reconstruction is improper positioning of the tunnel. Errors in femoral tunnel position may be related to poor visualization of the lateral wall. When anatomic double-bundle ACL reconstruction is performed, proper visualization of the lateral wall is essential to ensure correct placement of both tunnels. We propose the use of a central portal, in addition to more standard anterolateral and anteromedial portals, to enhance visualization of the lateral wall. In addition, the arthroscope can be moved interchangeably throughout the portals during the procedure for improved viewing during specific steps. An accessory anteromedial portal placed inferiorly and medially allows placement of the femoral tunnels while providing a high central anteromedial portal for best visualization of the lateral wall. As a result, no notchplasty is required, and a more anatomic reconstruction can be performed.     

Laser-Guided Placement of the Tibial Guide in the Transtibial Technique for Anterior Cruciate Ligament Reconstruction

In anterior cruciate ligament (ACL) reconstruction, it is important to determine the location and direction of the femoral bone tunnel when using the transtibial technique. Accurately identifying the anatomic location at which to make the femoral bone tunnel for double-bundle ACL reconstruction is not a straightforward procedure. We describe a new method in which the centrum of the femoral tunnel is marked with an awl and a laser beam–guided technique is used to place the tibial pin. This procedure allows us to mark the desired location of the femoral tunnel before drilling the tibial bone tunnel when using the transtibial technique. This is the first report of a laser-guided technique used in arthroscopic surgery. We used a laser beam to determine the location of the femoral tunnel—the anatomic site needed to perform the intra-articular drilling in the tibia. In this technique, a laser pointer is set at the tibial guide, which reflects the laser beam and illuminates the point where the femoral bone tunnel should be made. Our method offers an easy and accurate way to reconfirm the tibial placement before drilling.     

Arthroscopic anterior cruciate ligament reconstruction: An air-fluid medium to enhance visual clarity

We describe a surgical technique that has been used successfully during arthroscopic anterior cruciate ligament reconstruction to enhance the visual clarity of the operating field specifically during tunnel placement. The precise siting of both tibial and femoral tunnels is critical to both the short- and long-term success of this procedure. Gentle insufflation of the knee joint with air prior to tunnel siting allows for an excellent view of the intercondylar notch. This visual clarity helps in the precise placement and measurement of the femoral tunnel.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 3 (March), 2003: pp E22     

In vitro comparison of elongation of the anterior cruciate ligament and single- and dual-tunnel anterior cruciate ligament reconstructions.

This study evaluated strain in the normal anterior cruciate ligament (ACL) and compared it to four different double-strand hamstring tendon reconstructive techniques. Seventeen fresh-frozen knees from 11 cadavers were tested. The strain in the anteromedial and posterolateral bands of the native ACL and their equivalents in four autograft techniques were measured using differential variable reluctance transducers. The anteromedial band of the intact ACL shortened from 0 degree -30 degrees of flexion, then lengthened to 120 degrees; the posterolateral band of the intact ACL shortened from 0 degree - 120 degrees of flexion. Following ACL excision, these knees underwent reconstruction with double-strand hamstring tendons with either single tibial and femoral tunnels, single tibial and dual femoral tunnels, dual tibial and single femoral tunnels, or dual tibial and dual femoral tunnels. With the exception of the dual-band, dual-tunnel technique, all of the procedures placed greater strain on the reconstructive tissues than was observed on the native ACL, after approximately 30 degrees of flexion. These results indicate that dual-band hamstring tendon reconstructions placed with single tibial and femoral tunnels do not address the complexity of the entire ACL. Rather, these procedures appear to only duplicate the effect of the anteromedial band, while perhaps overconstraining the joint as a result of its inability to reproduce the function of the posterolateral band. During rehabilitation following ACL reconstruction, therefore, only from 0 degree - 30 degrees of the graft tissues are not significantly strained. Dual tibial and femoral tunnel techniques should be evaluated further to more closely recreate knee kinematics following ACL reconstruction.     

Effects of femoral tunnel placement on knee laxity and forces in an anterior cruciate ligament graft.

The purpose of this study was to measure the effects of variation in placement of the femoral tunnel upon knee laxity, graft pretension required to restore normal anterior-posterior (AP) laxity and graft forces following anterior cruciate ligament (ACL) reconstruction. Two variants in tunnel position were studied: (1) AP position along the medial border of the lateral femoral condyle (at a standard 11 o'clock notch orientation) and (2) orientation along the arc of the femoral notch (o'clock position) at a fixed distance of 6-7 mm anterior to the posterior wall. AP laxity and forces in the native ACL were measured in fresh frozen cadaveric knee specimens during passive knee flexion-extension under the following modes of tibial loading: no external tibial force, anterior tibial force, varus-valgus moment, and internal-external tibial torque. One group (15 specimens) was used to determine effects of AP tunnel placement, while a second group (14 specimens) was used to study variations in o'clock position of the femoral tunnel within the femoral notch. A bone-patellar tendon-bone graft was placed into a femoral tunnel centered at a point 6-7 mm anterior to the posterior wall at the 11 o'clock position in the femoral notch. A graft pretension was determined such that AP laxity of the knee at 30 deg of flexion was restored to within 1 mm of normal; this was termed the laxity match pretension. All tests were repeated with a graft in the standard 11 o'clock tunnel, and then with a graft in tunnels placed at other selected positions. Varying placement of the femoral tunnel 1 h clockwise or counterclockwise from the 11 o'clock position did not significantly affect any biomechanical parameter measured in this study, nor did placing the graft 2.5 mm posteriorly within the standard 11 o'clock femoral tunnel. Placing the graft in a tunnel 5.0 mm anterior to the standard 11 o'clock tunnel increased the mean laxity match pretension by 16.8 N (62%) and produced a knee which was on average 1.7 mm more lax than normal at 10 deg of flexion and 4.2 mm less lax at 90 deg. During passive knee flexion-extension testing, mean graft forces with the 5.0 mm anterior tunnel were significantly higher than corresponding means with the standard 11 o'clock tunnel between 40 and 90 deg of flexion for all modes of constant tibial loading. These results indicate that AP positioning of the femoral tunnel at the 11 o'clock position is more critical than o'clock positioning in terms of restoring normal levels of graft force and knee laxity profiles at the time of ACL reconstruction.     

Technique of anatomical footprint reconstruction of the ACL with oval tunnels and medial portal aimers

Purpose

The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible.

Technique and patients

The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan.

Results

There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions.

Conclusions

This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do.

Level of Evidence

Level IV, case series.     

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.