Single-Bundle Anterior Cruciate Ligament Reconstruction: Technique Overview and Comprehensive Review of Results

Transcription

1 67 COPYRIGHT 2008 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Single-Bundle Anterior Cruciate Ligament Reconstruction: Technique Overview and Comprehensive Review of Results By Lieutenant Commander John-Paul H. Rue, MD, Paul B. Lewis, MD, MS, A. Dushi Parameswaran, MD, and Bernard R. Bach Jr., MD Introduction The purpose of this scientific exhibit is to review the single-bundle anterior cruciate ligament reconstruction theory and technique, focusing on technical pearls used to avoid the most commonly encountered errors, and to provide a comprehensive review of outcomes after singlebundle anterior cruciate ligament reconstruction. Single-Bundle Theory vertically oriented femoral tunnel is one of the most common causes of failure after anterior cruciate ligament A reconstruction 1-3. In this situation, patients may demonstrate a normal result on the Lachman examination but have instability as demonstrated by a pivot shift phenomenon on clinical examination. As opposed to the two-incision anterior cruciate ligament reconstruction, in which the femoral and tibial tunnels are drilled independently of each other, the femoral tunnel position in a single-incision, transtibial technique is dependent on the position and orientation of the tibial tunnel. Problem: Instability Due to Vertical Graft When the transtibial, single-incision technique is used for reconstruction of the anterior cruciate ligament, it is possible for surgeons to inadvertently create a vertically oriented graft (Fig. 1). Such a vertical graft may not adequately restore either the translational or rotational kinematic properties of an intact knee. Clinical failure in these patients commonly presents as subjective instability, with a positive pivot shift, despite a negative result on the Lachman test. Anatomy: Anteromedial Bundle Provides Anterior Stability and Posterolateral Bundle Provides Rotational Stability To further investigate this problem, the contributions of the Fig. 1 Arthroscopic image of a vertically oriented anterior cruciate ligament graft in a right knee. This patient complained of instability, and the physical examination demonstrated a negative Lachman test with a positive pivot shift. Note that the arthroscopic probe is placed at the twelve o clock position. anteromedial and posterolateral bundles of the native anterior cruciate ligament have been studied. The anteromedial bundle has been shown to be located more toward the eleven o clock position in a right knee and primarily provides a restraint to anteriorly directed forces, while the posterolateral bundle is located more laterally near the nine o clock position and provides restraint to both anterior as well as rotational forces 4,5 (Fig. 2). Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated. Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States Government. J Bone Joint Surg Am. 2008;90 Suppl 4:35-9 doi: /jbjs.h.00651

2 68 Summary of Single-Bundle Theory With use of a transtibial technique, a lateralized femoral tunnel placed at the 10:30 position (right knee) places the anterior cruciate ligament graft at the midpoint between the anteromedial and posterolateral bundles of the native anterior cruciate ligament, effectively creating a hybrid anterior cruciate ligament reconstruction (Figs. 7-A and 7-B). Overview of the Single-Bundle Anterior Cruciate Ligament Reconstruction Technique s is common to most described anterior cruciate ligament Areconstruction techniques, a graft is placed through a tibial and a femoral bone tunnel to substitute for the native anterior cruciate ligament. There are three critical points to performing a single-bundle anterior cruciate ligament reconstruction with use of a transtibial drilled lateralized femoral Fig. 2 Cadaver dissection showing the anteromedial (AM) and posterolateral (PL) bundles of the anterior cruciate ligament. Anatomy: Lateralized Femoral Tunnel Reconstructs Portions of Both Anteromedial and Posterolateral Bundle Origins In a cadaver model, a lateralized, transtibial, drilled 10-mm femoral tunnel placed at approximately the 10:30 position (halfway between the ten and the eleven o clock position) has been shown to overlap approximately 50% of the anteromedial bundle and 51% of the posterolateral bundle 6 (Figs. 3, 4, and 5). Biomechanical Data: Lateralized Femoral Tunnel Position Restores Rotational Stability In biomechanical studies, an oblique femoral tunnel positioned laterally on the intercondylar wall has been shown to restore rotational stability, as well as anterior and posterior stability 7-9. Practical Application: A Lateralized Femoral Tunnel Can Be Achieved with Use of a Transtibial Technique A recent cadaver study has suggested that transtibial techniques that place a femoral tunnel within the anatomic footprint of the anterior cruciate ligament origin result in a shortened tibial tunnel and might compromise tibial fixation 10. In more than 1800 anterior cruciate ligament reconstructions by the senior surgeon (B.R.B. Jr.), this has not been found to be a problem. In contrast, we reviewed the postoperative radiographs of fifty consecutive knees that had a primary single-bundle anterior cruciate ligament reconstruction with use of a transtibial anterior cruciate ligament technique and found that we were reliably able to place the femoral tunnel at approximately the 10:30 position through a tibial tunnel angled approximately 60 in the coronal plane 11 (Fig. 6). Fig. 3 Schematic drawing of a clock face superimposed on a coronal image of a right knee. The clock face reference is a useful tool for coronal plane orientation. (Reprinted, with permission, from: Rue JH, Busam ML, Bach BR Jr. Hybrid single-bundle anterior cruciate ligament reconstruction technique using a transtibial drilled femoral tunnel. Tech Knee Surg. 2008;7: )

3 69 Notch Preparation The goal of the notchplasty is to create a space of 10 mm between the lateral wall of the intercondylar notch and the lateral edge of the posterior cruciate ligament to prevent impingement of the graft. The final configuration of the posterior intercondylar notch should resemble a smooth Roman arch as opposed to a sloped Gothic arch (Fig. 8) for easier placement of the aiming guide at the 10:30 position as the aiming device has a tendency to migrate vertically (i.e., toward the eleven o clock position) with a more steeply oriented notchplasty. Fig. 4 Cadaver dissection photograph showing the relationship of a 10-mm femoral tunnel to the anteromedial (AM) and posterolateral (PL) bundle origins of the anterior cruciate ligament. Tibial Tunnel Preparation The use of an accessory inferomedial portal (Fig. 9) placed through the patellar tendon one fingerbreadth lateral and distal to the medial portal allows improved rotational mobil- Fig. 5 Cadaver dissection photograph showing the lateralized orientation of a femoral tunnel placed at the 10:30 position (midway between the anteromedial and posterolateral bundle origins of the anterior cruciate ligament). (Reprinted, with permission, from: Rue JH, Busam ML, Bach BR Jr. Hybrid single-bundle anterior cruciate ligament reconstruction technique using a transtibial drilled femoral tunnel. Tech Knee Surg. 2008;7: ) tunnel. Each of the following steps is common to the vast majority of described anterior cruciate ligament reconstruction techniques: (1) A proper posterior over the top notchplasty in the shape of a smooth Roman arch aids in the placement and rotation of the femoral offset aimer. (2) The tibial tunnel orientation dictates femoral tunnel placement. The tibial tunnel should be placed at approximately 60 to the tibial articular surface. (3) The femoral offset aimer should be hooked in the over the top position and then rotated laterally to achieve the lateralized 10:30 position for a right knee (1:30 for a left knee). Fig. 6 The average position of the femoral tunnel corresponded to approximately the 10:30 position for a right knee (angle A) when drilled through a tibial tunnel oriented approximately 60 to the proximal tibial articular surface (angle B) in the coronal plane. (Reprinted, with permission, from: Rue JP, Ghodadra N, Lewis PB, Bach BR Jr. Femoral and tibial tunnel position using a transtibial drilled anterior cruciate ligament reconstruction technique: Technical note. J Knee Surg. 2008;21:246-9.)

4 70 Fig. 7-A Fig. 7-B Schematic (Fig. 7-A) and cadaver dissection photograph (Fig. 7-B) demonstrating the position of a hybrid femoral tunnel placed midway between the anteromedial (AM) and posterolateral (PL) bundle origins of the anterior cruciate ligament at approximately the 10:30 position for a right knee. (Figure 7-A reprinted, with permission, from: Busam ML, Provencher MT, Bach BR Jr. Complications of anterior cruciate ligament reconstruction with bone-patellar tendon-bone constructs: care and prevention. Am J Sports Med. 2008;36: Figure 7-B reprinted, with permission, from: Rue JH, Busam ML, Bach BR Jr. Hybrid single-bundle anterior cruciate ligament technique using a transtibial drilled femoral tunnel. Tech Knee Surg. 2008;7: ) ity of the tibial guide-pin aiming device and easier medialto-lateral (i.e., oblique) orientation of the aimer compared with when it is placed through the standard medial portal. The guide is set on the basis of the n + 10 rule, i.e., by adding 10 to the tendinous graft length to set the guide in degrees. For example, by following this rule with a typical graft length of 45 mm, the guide is set at 55. Alternatively, we select 55 on the aimer if it provides for a longer tibial tunnel. This modification of the n + 7 rule assists in matching the graft and tunnel lengths 12. As the femoral tunnel placement is impacted by the tibial tunnel orientation (Fig. 10), this technique also allows the surgeon to ensure that the femoral tunnel entrance is appropriately oriented obliquely on the femur. The tibial tunnel is typically placed at approximately 60 to the tibial articular surface in the coronal plane. Accurate pin placement follows four parameters: (1) placement in the posterior aspect of the tibial anterior cruciate ligament footprint; (2) 5 mm lateral to the medial tibial spine; (3) 7 mm anterior to the posterior cruciate ligament; and finally (4) confirmation that the tibial pin is posterior to the intercondylar apex with the knee in complete extension. Once the tibial guide-pin is properly positioned, it is overreamed with a cannulated reamer 1 mm larger than the tibial bone block (typically 10 or 11 mm) or the same diameter as a soft-tissue graft. This reduces the likelihood of delamination of the graft during passage. A chamfer reamer and curved hand rasp are used to smooth the posterior edge of the tunnel s intra-articular opening. This step aids in the subsequent positioning of the femoral offset aimer in the correct lateralized and posterior orientation and ensures a smooth posterior surface on which the graft will lie. Femoral Tunnel Preparation The primary goal in drilling the femoral tunnel is to position it within the anatomic footprint of the anteromedial and posterolateral bundles of the anterior cruciate ligament at the 10:30 position on a right knee (or the 1:30 position on a left knee). To reduce the possibility of a posterior wall blowout, a 7-mm offset guide is used if a 10-mm femoral tunnel is to be drilled, leaving a 2-mm posterior cortical bone shell. The femoral offset guide is inserted retrograde through the tibial tunnel and is hooked over the over the top position (Fig. 11-A) and rotated laterally (Fig. 11-B) to achieve the final desired orientation at the 10:30 position on a right knee (the 1:30 position on a left knee). A femoral tunnel footprint is reamed 8 to 10 mm into the femur before fully reaming the tunnel. This footprint is then inspected and probed to confirm cortical integrity and an appropriate posterior cortical wall thickness of 1 to 2 mm (Fig. 12) prior to reaming the tunnel to a depth of 30 to 35 mm. The femoral bone plug is inserted with the cortex oriented posteriorly. The interference screw is placed anterior to and slightly toward the midline of the femoral bone plug (Fig. 13). This fi-

5 71 Fig. 8 The final notchplasty configuration should resemble a smooth Roman arch as opposed to a pointed Gothic arch. (Reprinted, with permission, from: Rue JH, Busam ML, Bach BR Jr. Hybrid single-bundle anterior cruciate ligament reconstruction technique using a transtibial drilled femoral tunnel. Tech Knee Surg. 2008;7: ) Fig. 10 Schematic illustration demonstrating the influence of differing tibial tunnel orientations on the femoral tunnel position. As the femoral tunnel placement is impacted by tibial tunnel orientation, it is imperative that the surgeon anticipate the appropriate tibial tunnel angle in order to obtain the desired lateralized position of the femoral tunnel. This angle is typically 60 to the tibial articular surface in the coronal plane. (Reprinted, with permission, from: Rue JH, Busam ML, Bach BR Jr. Hybrid single-bundle anterior cruciate ligament reconstruction technique using a transtibial drilled femoral tunnel. Tech Knee Surg. 2008;7: ) Fig. 9 Intraoperative photograph of a right knee showing the use of an accessory inferomedial (IM) portal (arrow). The tibial guide-pin aiming arm is placed through the accessory inferomedial portal to improve rotational mobility. Note the superomedial (SM) outflow portal. nal step places the graft in the most posterior and lateralized position possible. The graft is then viewed arthroscopically in both flexion and extension to assess orientation and tension and to ensure that there is at least 3 to 5 mm of clearance between the graft and the roof of the notch in extension and that there is no impingement on the posterior cruciate ligament (Figs. 14-A and 14-B). Results of Single-Bundle Anterior Cruciate Ligament Reconstruction Spindler et al. 13 performed a systematic review of patellar

6 72 review, instead, established an unbiased database of outcomes after single-bundle anterior cruciate ligament reconstruction for comparison with forthcoming data on alternative surgical techniques. The clinical follow-up in their systematic review consisted of 911 patients at a minimum two-year follow-up. It is worth noting that the study group had an appreciable number of reported concomitant injuries. At the time of follow-up, the International Knee Documentation Committee (IKDC) system grades were reported for 766 subjects 14. The outcome was graded as A or B for 568 patients (74%) and as C or D for 198 patients (26%). The overall prevalence of anterior knee pain was found to be 23% (eighty-eight of 378 patients). Nevertheless, 93% of the sub- Fig. 11-A Fig. 11-B The femoral offset guide is positioned and rotated laterally (Fig. 11-A) to achieve the proper oblique orientation (the 10:30 position on a right knee and the 1:30 position on a left knee) (Fig. 11-B). (Reprinted, with permission, from: Rue JP, Ghodadra N, Lewis PB, Bach BR Jr. Femoral and tibial tunnel position using a transtibial drilled anterior cruciate ligament reconstruction technique: Technical note. J Knee Surg. 2008;21:246-9.) tendon and hamstring autografts and their clinical outcomes and concluded that there were no significant differences between these graft types. On the basis of this conclusion, we performed a comprehensive systematic review of these grafts collectively to establish a baseline, whereby double-bundle reconstructions could be compared with single-bundle reconstructions. Lewis et al. 14 performed a systematic review of eleven randomized, controlled trials and combined the results of the graft choices to objectively define the success of single-bundle anterior cruciate ligament reconstruction. Their review compared neither graft choice nor reconstruction technique. The Fig. 12 A femoral tunnel footprint is reamed 8 to 10 mm into the femur before fully reaming the tunnel to ensure the posterior wall cortical integrity. Fig. 13 The femoral interference screw is placed anterior to and toward the midline of the femoral bone plug. This final step places the graft in the most posterior and lateral position possible.

7 73 Fig. 14-A Fig. 14-B Arthroscopic image of the final orientation of the anterior cruciate ligament graft in flexion (Fig. 14-A) and extension (Fig. 14-B), demonstrating proper orientation and tension and the absence of impingement. jects were satisfied with their outcome, and 335 (79%) of 424 subjects had returned to their preinjury level of sports by the time of follow-up. In their review, Lewis et al. reported that 577 (81%) of 712 reconstructions with data available had a negative pivot shift test and 135 (19%) had an abnormal pivot shift 14. Of the positive pivot shift results, 129 knees were further stratified, with ninety-seven (75%) graded as 1+, twenty-four (19%) graded as 2+, and eight (6%) graded as 3+ pivot shifts. Of the 598 reported Lachman tests, 354 (59%) were negative. Of the 244 knees with a positive result, 220 (90%) were reported to have only a mild difference in anterior displacement with a firm end point. Arthrometric evaluation of anterior-posterior stability was reported for 358 patients. Of the studied subjects, 274 knees (77%) had a side-to-side difference of <3 mm. There was no loss of extension or hyperextension in 382 (54%) of 701 reported knees 14. The loss of active extension or the presence of hyperextension was 5 in 634 (90%) of the 701 subjects. No loss of flexion was reported for 290 (78%) of 372 subjects. Additional details about loss of flexion were limited by inconsistently reported ranges of flexion loss. Lewis et al. found that three studies had noted no radiographic evidence of degenerative changes in the 271 subjects at the time of a minimum two-year follow-up. Graft failure was reported in thirty-two (3.5%) of the 911 reconstructions. Twenty-five graft failures (78%) were due to traumatic rupture, and seven were detected clinically. Practicing orthopaedic surgeons must balance their comfort in performing established procedures with the need to adapt to improved understanding of the biomechanics of anterior cruciate ligament reconstruction. The outcome results presented above are intended to provide assistance in evaluating and comparing the potential benefits of newer techniques, such as double-bundle anterior cruciate ligament reconstruction, and the established standards with use of a traditional single-bundle technique. Discussion ith a few minor adjustments, surgeons can adapt their Wown current single-bundle anterior cruciate ligament reconstruction technique to accomplish the same lateralized femoral tunnel position highlighted in this presentation. While the primary emphasis of this technique overview is on the steps that will aid in placing the femoral tunnel in the lateralized position between the anteromedial and posterolateral bundles, it is important to note that coronal orientation constitutes only part of the proper placement of the femoral tunnel. Sagittal positioning of the femoral tunnel along the posterior aspect of the intercondylar notch is also important in order to accurately reconstruct the native anterior cruciate ligament. In our hands, using these techniques, single-bundle anterior cruciate ligament reconstruction has consistently yielded high rates of stability and subjective patient satisfaction, with low revision rates over many years of experience. Lieutenant Commander John-Paul H. Rue, MD National Naval Medical Center, 8901 Rockville Pike, Bethesda, MD address: johnpaulrue@gmail.com Paul B. Lewis, MD, MS A. Dushi Parameswaran, MD Bernard R. Bach Jr., MD Division of Sports Medicine, Department of Orthopaedic Surgery, Rush University Medical Center, 1725 West Harrison Street, Suite 1063, Chicago, IL 60612

8 74 References 1. George MS, Dunn WR, Spindler KP. Current concepts review: revision anterior cruciate ligament reconstruction. Am J Sports Med. 2006;34: Jaureguito JW, Paulos LE. Why grafts fail. Clin Orthop Relat Res. 1996; 325: Johnson DL, Fu FH. Anterior cruciate ligament reconstruction: why do failures occur? Instr Course Lect. 1995;44: Mochizuki T, Muneta T, Nagase T, Shirasawa S, Akita KI, Sekiya I. Cadaveric knee observation study for describing anatomic femoral tunnel placement for twobundle anterior cruciate ligament reconstruction. Arthroscopy. 2006;22: Yasuda K, Kondo E, Ichiyama H, Kitamura N, Tanabe Y, Tohyama H, Minami A. Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts. Arthroscopy. 2004;20: Rue JP, Ghodadra N, Bach BR Jr. Femoral tunnel placement in single-bundle anterior cruciate ligament reconstruction: a cadaveric study relating transtibial lateralized femoral tunnel position to the anteromedial and posterolateral bundle femoral origins of the anterior cruciate ligament. Am J Sports Med. 2008; 36: Scopp JM, Jasper LE, Belkoff SM, Moorman CT 3rd. The effect of oblique femoral tunnel placement on rotational constraint of the knee reconstructed using patellar tendon autografts. Arthroscopy. 2004;20: Yamamoto Y, Hsu WH, Woo S, Van Scyoc AH, Takakura Y, Debski RE. Knee stability and graft function after anterior cruciate ligament reconstruction: a comparison of a lateral and an anatomical femoral tunnel placement. Am J Sports Med. 2004;32: Loh JC, Fukuda Y, Tsuda E, Steadman RJ, Fu FH, Woo SL. Knee stability and graft function following anterior cruciate ligament reconstruction: comparison between 11 o clock and 10 o clock femoral tunnel placement. Arthroscopy. 2003;19: Heming JF, Rand J, Steiner ME. Anatomical limitations of transtibial drilling in anterior cruciate ligament reconstruction. Am J Sports Med. 2007;35: Rue JP, Ghodadra N, Lewis PB, Bach BR. Femoral and tibial tunnel position using a transtibial drilled anterior cruciate ligament reconstruction technique. J Knee Surg. 2008;21: Olszewski AD, Miller MD, Ritchie JR. Ideal tibial tunnel length for endoscopic anterior cruciate ligament reconstruction. Arthroscopy. 1998;14: Spindler KP, Kuhn JE, Freedman KB, Matthews CE, Dittus RS, Harrell FE Jr. Anterior cruciate ligament reconstruction autograft choice: bone-tendon-bone versus hamstring: does it really matter? A systematic review. Am J Sports Med. 2004;32: Lewis PB, Parameswaran AD, Rue JP, Bach BR Jr. Systematic review of singlebundle anterior cruciate ligament reconstruction outcomes: a baseline assessment for consideration of double-bundle techniques. Am J Sports Med In press.