Double-Bundle Anterior Cruciate Ligament Reconstruction

Chapter 78


Double-Bundle Anterior Cruciate Ligament Reconstruction





Chapter Synopsis



• Anterior cruciate ligament (ACL) reconstruction is a common surgical procedure, yet there is no single universally accepted reconstructive technique.


• Single-bundle reconstruction is most commonly done, but debate is ongoing as to whether it should be done with the traditional transtibial approach for drilling the femur, or via an independent drilling technique on the femur either through the anteromedial (AM) portal or via a lateral two-incision type of approach.


• More recently, with recognition of the tendency for a vertical nonanatomic graft if the reconstruction is done transtibially, attention has focused on an anatomic single-bundle reconstruction through independent drilling.


• An alternative to an anatomic technique in ACL reconstruction is to perform a double-bundle ACL reconstruction.


• As with single-bundle ACL reconstruction, there are different ways to perform a double- bundle ACL reconstruction.


• This chapter focuses on the all-inside procedure, which is the most minimally invasive technique for double-bundle ACL reconstruction.



Important Points



• A hallmark surgical indication for ACL reconstruction is the subjective sensation of giving way, correlated with objective pivot-shift test results on examination.


• The normal ACL has two primary bundles—anteromedial (AM) and posterolateral (PL).


• Experimental studies have shown benefit to the addition of a PL bundle for rotational stability.


• Two grafts provide potential for better isometry with some portion of graft material tight through full range of motion.


• The all-inside technique is conceptually different via creation of a retrograde tibial socket from inside the joint—not a full tunnel—thereby being innately less invasive; clinically, the procedure seems less painful.


• No transtibial drilling; the procedure involves independent drilling of femoral and tibial sockets with the femur drilled either through the AM portal or “outside-in” as in a two-incision approach.


• An all-inside technique is versatile relative to graft choice; choices include patellar or quadriceps tendon, hamstring autograft or allograft, or a combination thereof.



Clinical and Surgical Pearls



• Issue of graft length in PL socket: Owing to bony anatomy relative to the width of the lateral femoral condyle, the intraosseous distance for the PL bundle is shorter. The goal is to have at least 20 mm of graft in the PL socket for optimal healing. It is preferable not to use an accessory medial portal because that would create an angle of approach to the femur that is too perpendicular and thus further shorten the intraosseous distance. With use of a low AM portal, it is possible to orient the guide pin more obliquely from the femoral starting point to make for a longer intraosseous distance, which is the key to maximal graft in the femoral socket.


• The proprietary RetroCutter (Arthrex, Naples, FL) provides optimal circular cuts for tibial sockets to minimize aperture fragmentation and also maximize space available for two separate tibial sockets to avoid the risk of coalescence. In addition, this device make visualization of the socket position technically easier.


• PL bundle tibial socket creation: It is critical to initiate the starting point on the tibia with the RetroCutter guide pin close to the midline; this greatly facilitates later passage of the RetroScrew (Arthrex) from inside the joint for graft fixation. Otherwise, it is difficult to place the RetroScrew on the driver if not centered in notch.


• A helpful step for RetroScrew fixation of both bundles on the tibia is dilating over a tibial guide wire with the RetroScrewdriver (Arthrex) before placing the RetroScrew. This provides more room for the RetroScrew to fixate anterior to the graft filling the socket.


• Use a cannula through the AM portal when passing grafts to avoid getting sutures caught in the soft tissue (i.e., fat pad), which can be very frustrating.


• Fix the PL bundle in full extension because the biomechanics of knee motion involves tightening of the PL bundle by 2 to 3 mm as the knee is extended. If the PL bundle is not fixed in full extension, either the joint will be overconstrained and extension will be limited, or the PL graft will stretch and fail.



Clinical and Surgical Pitfalls



• Measurement of graft length is critical with the all-inside technique because femoral and tibial sockets are fixed lengths, along with intra-articular distance; otherwise, grafts could “bottom out” and be lax.


• AM portal drilling for femoral socket creation: Drill the PL socket first to make sure it is not positioned too distally toward the weight-bearing surface of the lateral femoral condyle; if the AM bundle is drilled first, the surgeon risks not leaving enough room for the PL. If the injury is chronic and there are no remaining native PL and AM fibers for orientation for the sockets, the approach is to be sure that both sockets are positioned posterior to the lateral intercondylar ridge (“resident’s ridge”) with 2 mm between the sockets and 3 to 4 mm intact from the distal lateral femoral condyle articular surface for the PL bundle.


• If the surgeon is uncomfortable with AM portal drilling, another option is to use an outside-in approach with the FlipCutter (Arthrex). This is a proprietary guide pin that easily converts to a reamer for creation of the femoral sockets from a lateral drilling position.


• If a patient has a small tibial footprint, double-bundle ACL reconstruction may not be feasible. An intra-articular measuring device is used, and if the distance from the front of the posterior cruciate ligament (PCL) to the anterior margin of the ACL footprint is at least 18 mm, all-inside double-bundle ACL reconstruction is possible. The RetroCutter greatly facilitates the double-bundle procedure because it achieves true circular sockets on the tibia, which take up less room than transtibial tunnels; transtibial tunnels create a wider more oval aperture upon entering the knee joint, with a higher propensity for aperture microfracturing.





Preoperative Considerations


An acute anterior cruciate ligament (ACL) tear is typically related to a “giving way” episode, and a noncontact rotational injury is quite common, particularly in football and soccer. Deceleration and landing from a jump are classic mechanisms of injury in basketball players. Patients usually have early swelling with an acute tear consistent with hemarthrosis, and resultant limited motion—especially extension. One should have a high level of suspicion with young female basketball or soccer players who hurt the knee and have diffuse pain and swelling with a difficult examination; an ACL tear should be presumed until proven otherwise. In the chronic setting, patients relate instability with twisting and pivoting, and may also note catching or locking if they have an associated meniscus tear.


Physical examination for an ACL tear is predicated on determination of both pathologic anterior and rotational joint laxity compared with the normal knee. The Lachman test at 30 degrees of flexion is easily done even in the acute setting and is very sensitive for anterior laxity. The pivot-shift maneuver is really the key test, however, because it is diagnostic for rotational instability, which is the disabling feature of an ACL tear—that is, the mechanism that puts the knee at risk for giving way. Joint line tenderness should raise suspicion for a meniscus tear, especially if pain and/or a pop is present with provocative knee flexion and rotation testing. In the acute setting, lateral joint tenderness may be more related to the common associated bone contusion injury pattern to the lateral femoral condyle anteriorly and the lateral tibial plateau posteriorly.


Standard imaging for an ACL injury includes weight-bearing radiographs, especially important in patients with chronic ACL deficiency to assess for degenerative change or malalignment. Magnetic resonance imaging (MRI) is helpful in acute injury to quantify the extent of lateral compartment bone contusion, which is important relative to consideration of a period of non–weight-bearing time to protect the lateral compartment articular surfaces, particularly if there is associated chondral injury. In the chronic setting, subtle degenerative chondral changes may be seen. MRI is also very useful to assess the status of the collateral ligaments if there is any question of the need for repair or reconstruction of the medial or lateral-PL ligament complex at the time of ACL reconstruction. MRI, of course, also provides valuable information relative to the status of the menisci. Certainly, accurate knowledge about the state of the secondary stabilizers relative to the collateral ligaments and the menisci, along with the condition of the articular surfaces, is helpful for surgical planning.


Options for ACL reconstruction include single-bundle versus double-bundle procedures. In the realm of single-bundle procedures, recent experimental and clinical work has highlighted the potential for vertical graft placement with traditional transtibial drilling of the femur, which in turn can lead to residual instability. This has spawned the term “anatomic” single-bundle reconstruction done with independent drilling of the femur and tibia. The femoral socket can be drilled either through the anteromedial (AM) portal or outside-in, either with a two-incision technique for guide pin placement from the lateral femur into the joint for reaming, or less invasively with a FlipCutter (Arthrex, Naples, FL), which is a guide pin that converts easily to a reamer. Given the fact that the native ACL has at least two major bundles—AM and posterolateral (PL)—an alternative approach would be double-bundle reconstruction, which would conceptually result in an even more anatomic reconstruction.


Certainly, there are numerous ways to perform a double-bundle ACL reconstruction. The overall goal regardless of the chosen technique is to achieve anatomic placement of graft tissue to recreate both the AM and the PL bundles. In its purest sense, double-bundle reconstruction is done with two separate tunnels in the femur and tibia. However, there are described “double-bundle ACL” techniques that use one tibial tunnel with two femoral tunnels, as well as techniques that use one tibial tunnel and one femoral tunnel with splitting of the graft into “bundles” with the fixation used. For a true double-bundle reconstruction, full tibial tunnels are usually created with guides by drilling into the joint from the proximal tibia. The femoral tunnels are then created transtibially, from the AM portal, or via a lateral two-incision type of approach. This chapter outlines the all-inside procedure, which is the most minimally invasive way to perform a double-bundle reconstruction. In the procedure to be detailed, two separate femoral sockets are drilled through the AM portal, and two separate tibial sockets are created in a retrograde manner from within the joint. Fixation is dependent on graft choice but generally consists of suspensory fixation on the femur with retrograde aperture screw fixation on the tibial side.


All-inside ACL reconstruction is based on the principle of creating a tibial socket by reaming from within the joint, as opposed to a traditional full tibial tunnel reamed from outside in. In addition, graft fixation on the tibial side is also done in retrograde fashion with placement of a fixation screw from within the joint. This was originally described in 2006 for single-bundle ACL reconstruction and was termed “no-tunnel“ reconstruction”1 and subsequently was first reported for double-bundle reconstruction in 2008.2 The driving force for the all-inside technique is its innate minimal invasiveness; the tibial socket is created through a small incision with a 3.0-mm-diameter pin, leading to less overall tibial soft tissue dissection. The key technologic advance is use of the RetroCutter (Arthrex) device. The other major difference from a traditional ACL reconstruction done through a full tibial tunnel is use of the RetroScrew (Arthrex) placed also from inside the joint for aperture fixation. Anecdotally, it was appreciated early on that patients seemed to have less pain postoperatively with the all-inside technique. Currently, a level I study comparing standard endoscopic single-bundle soft tissue allograft ACL reconstruction with an all-inside approach is being completed with 2-year follow-up data collection. Preliminary results confirm significantly less pain with visual analogue scale (VAS) scoring with the all-inside technique at all follow-up timeframes up to 2 years. It is important to note that no difference in outcome scores with International Knee Documentation Committee (IKDC) and Knee Society Score (KSS) scales has been seen (Smith and colleagues, unpublished data).


Potential indications for double-bundle reconstruction include athletes for whom rotational stability is paramount, particularly in position-dependent situations—for example, running backs, wide receivers, linebackers, and defensive backs in football. Patients who demonstrate inherent physiologic laxity with excessive knee hyperextension also may be appropriate candidates. Finally, for certain revision procedures the double-bundle approach may be most suitable.


A relative shortcoming of double-bundle reconstruction includes the need for harvesting two grafts when one wants to use autograft tissue. Certainly, the procedure is easily performed with two allografts—as illustrated in the surgical case presented in this chapter—but in young athletes, autograft tissue is generally preferable. Initially the all-inside double-bundle procedure with autograft tissue in young athletes was done with use of a doubled semitendinosus graft for the AM bundle and a doubled gracilis for the PL bundle, but a rerupture rate of approximately 7% (Smith, unpublished data) for that group on return to play was considered to be unacceptable. It was speculated that the doubled gracilis tendon was not strong enough for the stresses placed on the PL bundle, especially with joint loading in extension with athletic activity. This led to use of a patellar tendon autograft for the AM bundle and a doubled semitendinosus for the PL bundle in athletes, which has resulted in an acceptable rerupture rate of only 1.5% (Smith, unpublished data). However, this procedure requires use of both the patellar tendon and the semitendinosus, which prevents their use later if failure should occur. In that setting, I have found that an autograft quadriceps tendon single-bundle revision procedure has worked well.


A potential contraindication relates to the difficulty of a revision ACL reconstruction after a double-bundle procedure. The all-inside technique has an advantage in that regard, because creation of tibial sockets—not full bone tunnels—is inherently bone saving. Therefore a single-stage revision reconstruction has not been a problem, and I have even performed revision all-inside double-bundle reconstruction after a failed all-inside double-bundle construction.



Surgical Technique


The all-inside double-bundle ACL reconstruction discussed here is a case study of a left knee repaired with use of two semitendinosus soft tissue allografts. The PL bundle graft is 7.5 mm in diameter, and the AM bundle graft is 8.0 mm in diameter. The following is an overview of the procedure: Both the PL and AM femoral sockets are first created through the AM portal in hyperflexion for optimal anatomic positioning. Next, the PL tibial socket is created with the RetroCutter from a midline approach. The PL graft is passed and fixated on the femoral side with the suspensory TightRope device (Arthrex), and on the tibial side with a RetroScrew in full extension. The AM tibial socket is then created with the RetroCutter, and this graft is passed and fixed on the femur with the TightRope and on the tibial side with another RetroScrew at 30 degrees of knee flexion. A key point with all-inside surgery is accurate determination of graft length to ensure that a graft does not “bottom out,” which would make it lax at time zero. This is easily accomplished by knowing the depth of each graft in the femoral and tibial sockets in addition to measuring the intra-articular length of both grafts. Then, 5 to 10 mm is added to the reamed depth of each tibial socket to accommodate tensioning of each bundle and to ensure that neither graft will be too long.



Specific Steps


Box 78-1 outlines the specific steps of this procedure.



Box 78-1   Surgical Steps



Related posts:

Open Repair of Posterior Shoulder Instability Autologous Chondrocyte Implantation in the Knee Allografts for Anterior Cruciate Ligament Reconstruction All-Inside Anterior Cruciate Ligament GraftLink Technique: Second-Generation, No-Incision Anterior Cruciate Ligament Reconstruction Primary Repair of Osteochondritis Dissecans in the Knee Arthroscopic Meniscus Repair: All-Inside Technique

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Sep 11, 2016 | Posted by in SPORT MEDICINE | Comments Off on Double-Bundle Anterior Cruciate Ligament Reconstruction

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