Lateral Extra-articular Tenodesis in ACL Reconstruction

Abstract

Background:

Following anterior cruciate ligament (ACL) reconstruction, rotational instability is thought to be a key contributor to the development of arthritis and may be one reason for decreased postoperative patient satisfaction. Multiple studies have shown that ACL reconstructions may leave patients with deficiencies in rotational stability when compared to the native knee. While the posterior lateral bundle of the ACL is considered the primary rotational stabilizer of the knee, the anterolateral complex also helps to impart additional rotatory stability and has drawn attention as a source for supplemental rotational stability after ACL injury via a lateral extra-articular tenodesis (LET).

Indications:

The anterolateral complex helps provide rotational stability to the knee, and LET should be considered following ACL injury for patients with a high-grade pivot shift, generalized ligamentous laxity, younger age with a desire to return to pivoting activities, or failed prior ACL reconstruction.

Technique Description:

Over the lateral aspect of the knee, Gerdy’s tubercle and the lateral epicondyle are identified. A 4-cm incision is created just posterior and proximal to the epicondyle to facilitate the graft harvest and the creation of a tunnel for the LET just proximal and posterior to the epicondyle to match the origin of the anterior lateral ligament (ALL). An iliotibial (IT) band graft is harvested, maintaining its distal insertion to Gerdy’s tubercle, and is passed medial to the fibular collateral ligament. A tunnel is drilled at the anatomic origin of the ALL with its trajectory aimed away from the femoral ACL tunnel, and the graft is secured with a suture anchor.

Results:

In the appropriate patient, ACL reconstruction with concomitant LET has been shown to confer a significantly lower clinical failure rate likely stemming from a reduced pivot shift and decreased forces on the ACL graft.

Discussion:

In vivo and in vitro studies have shown that ACL reconstruction reliably restores the knee’s anterior to posterior stability, but rotational stability remains significantly different between reconstructed and native ACLs. Rotational instability is thought to be a key contributor to the development of arthritis and may be one reason for decreased postoperative patient satisfaction. Performing LET in conjunction with ACL reconstruction decreases postoperative rotational instability and may decrease ACL failure in appropriately selected patients.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Background

More and more athletes are getting started at a high level of sport at an early age.^1,11,23 This is great but comes at a price, as there is an increasing number of injuries in this young and demanding athletic population with a high rate of reinjury.^1,11,23 At present, there are nearly 200,000 anterior cruciate ligament (ACL) reconstructions performed annually, with some populations having roughly a 25% chance of graft failure. ²³

When we think about assessing the integrity of the ACL, we first assess the anterior-posterior (AP) integrity of the knee in the form of Lachman and anterior drawer. Furthermore, our interest in restoring AP stability of the knee has led many to use devices like the KT-1000 to assess this postoperatively.^2,3,14 Our focus on restoring the anterior to posterior integrity of the knee has resulted in excellent ability to restore stability in this plane with ACL reconstruction; where we are lacking is control of rotatory stability, with numerous reports showing that we are not always effective at restoring the rotational stability needed by our high-demand patients.^4,10,19,21 In this study, Ristanis et al ¹⁹ performed an in vivo investigation of rotational knee stability by analyzing the maximum range of motion of tibial rotation during a high-demand activity analogous to the demands of high-level sport and showed a significant difference in rotational stability between ACL reconstructions and healthy controls. This rotational instability is thought to be a key contributor to the long-term development of osteoarthritis and has been implicated as one reason for lack of complete patient satisfaction after ACL reconstruction.^12,13,16

Given this, we were left searching for other possible strategies for restoring rotational stability. While the posterolateral bundle of the ACL is considered the primary rotational stabilizer, the anterior lateral ligament (ALL) complex also helps to impart rotatory stability of the knee joint and has drawn attention as a source for passport rotational stability after ACL injury. ⁸ Over the years as people became more and more interested in the rotational instability after ACL injuries, it has become increasingly more evident that rotational instability after ACL rupture and anterolateral complex injuries are extremely commonly seen together and go hand in hand. For instance, in this 2017 study out of Italy, they identified that ACL injury present in 90% of ACL tears and the high-grade pivot shifters were strongly correlated with having ACL injury. ⁵

Given this growing body of evidence, it is next important to figure out which patients would benefit from a lateral extra-articular tenodesis (LET). Rowan et al ²⁰ proposed a series of major and minor criteria, suggesting any patient with a high-grade pivot or undergoing a revision reconstruction would benefit from a LET as well as any patient with 2 or more minor criteria. The international ALL complex consensus group established a similar recommendation, suggesting LET in patients undergoing revision ACL reconstruction, with a high-grade pivot or generalized ligamentous laxity, and young patients returning to pivoting activities. ⁶  With the importance of the ALL established, we can now turn our attending to how it should be fixed or augmented.

Indications

This is a case of a right knee, quadriceps tendon ACL reconstruction augmented with LET in an active mixed martial arts athlete. Prior to any arthroscopic work being done, the iliotibial (IT) band graft is prepared and tunnels are created.

Technique Description

On the lateral aspect of the knee, we mark out Gerdy’s tubercle, the lateral epicondyle, and a 4-cm incision just posterior and proximal to the epicondyle. This will allow us to drill our inside-out ACL tunnel while also drilling the tunnel and fixing the LET just proximal and posterior to the epicondyle to match the origin of the ALL.^15,18 This incision may look proximal, but you will notice that after developing subcutaneous flaps above the IT band, you are able to get plenty of exposure distally down to nearly Gerdy’s tubercle. We prefer to make an incision with the knee in flexion. Incision is made down to the IT band, and subcutaneous flaps are created. Take care when dissecting near the femoral attachment to avoid the superolateral genicular artery, which should be avoided or coagulated to prevent unnecessary bleeding and postoperative hematoma. As shown here, we use the Cobb elevator to strip the mobile tissue overlying the IT band to better define and identify its posterior border.

At the proximal portion of our incision, we start our IT band graft harvest site, leaving a small cuff of posterior tissue to facilitate fascia-to-fascia closure at the end of the case. We then travel in a curvilinear fashion distally to Gerdy’s tubercle. At this stage, care must be taken not to cut too deeply as the fibular collateral ligament (FCL) may be damaged. We then create a parallel cut about 1 cm anteriorly and transect the proximal portion of the graft. It is important not to transect the graft before completing both longitudinal cuts so as to maintain control of the graft. Our graft is typically around 7 cm in length, but we have found that if you see muscle underlying the proximal portion of your graft, you have enough length for your graft. This is only reliable for anchor fixation, however, and one should keep in mind that additional graft would be required if utilizing a socket for graft fixation. We then dissect away the IT band graft, traveling proximal to distal to the level of Gerdy’s tubercle. Again, you can see that despite a slightly proximal incision, you can really mobilize the skin sufficiently to expose distally to the tubercle. We then identify the FCL, following and confirming its origin up to the lateral epicondyle. We then create longitudinal slits just anterior and posterior to the FCL to facilitate creation of a path for our IT band graft. We then utilize a passing stitch and subsequently pass our graft from distal to proximal, now traveling deep to the FCL, taking care to ensure the graft does not become twisted upon itself during passage.

Using electrocautery, we again identify the femoral insertion of the FCL and lateral epicondyle, and we expose our LET insertion site just proximal and posterior to the lateral epicondyle, ensuring dissection down to the bone. We aim our trajectory, going proximal and anteriorly, so that we can avoid our femoral tunnel for ACL, which we know will be directed more distal in a reliable way. We prefer to use the Arthrex hybrid, all-suture knee FiberTac anchor. With good retraction and counter-force on the medial aspect of the knee, the femoral socket is drilled proximally and anteriorly while maintaining hand position and inserting and fully seating the anchor. Once the sutures from the all-suture anchor are uncleated, the insertion handle is removed, and the anchor is set so that the all-suture anchor unloads in the cancellous bone and achieves good fixation.

At this point in time, we are done with our LET for now and will complete the arthroscopic portion of the case. We clamp the all-suture anchor sutures to the bed to facilitate suture management. We have not found fluid extravasation to be a problem when doing the LET harvest before arthroscopy. Here were are using the Arthrex Flipcutter to create our outside-in ACL femoral tunnel. You can see that this is placed just distal to our anchor for the LET, and the angle is different from that of the trajectory of the anchor for the LET—reliably ensuring that the 2 tunnels do not interfere.

Now that the ACL has been fixed, we maintain the leg at around 60° of knee flexion with neutral tibial rotation, either using a paint roller bump or leg holder. It is important to repeatedly check that you are maintaining a neutral tibial position to prevent malrotation. You can see here the distal blue and white sutures correspond to our femoral button from previous ACL fixation, which is in close proximity to the LET anchor. These sutures are removed. Using the blue looped passing suture, we then place the proximal IT band graft through the loop and pull the graft to its femoral insertion. It is very important not to overconstrain the knee, and thus care is taken not to apply too much tension to the graft. The graft is secured with a knotless loop in an onlay fashion, and the knee is brought through a full range of motion, ensuring the graft has been placed isometrically and the joint is not overconstrained. You can see that we have sufficient length of our graft, and if there is any remaining IT band, this can be cut, or for additional fixation, this can be sewn back onto itself or even to the LCL to provide another means of fixation. After completing the LET, it is important to completely close the IT band to prevent muscle herniation, which can be symptomatic.

Results

Here you can see our typical postoperative protocol for ACL reconstruction and LET. As discussed throughout the video, on screen you will find common pearls and pitfalls associated with our LET.

Discussion/Conclusion

While we previously showed how the absence of the ALL increases rotational instability, we are left wondering if fixing it actually helps. But the biomechanical data are pretty compelling that in the right patients, LET reduces pivot. In this study, Herbst et al ⁹ showed that when ACL and ALL injury are present, ACL reconstruction and LET reduced pivot shift and anterior translation significantly, whereas anatomic ACL reconstruction did not. This is further supported by the study by Marom et al, ¹⁷ showing that combining LET with ACL reconstruction resulted in a decrease in ACL graft force of up to 80% with pivot loads. Furthermore, these outcomes have translated into clinical data, with this prospective, randomized study in high-level female athletes showing that over half of patients with an ACL reconstruction only have residual pivot shift, whereas <20% have a positive pivot when undergoing an ACL reconstruction with an LET. ²² Finally, this study, which assessed rates of ACL reconstruction failure in patients at high risk of rerupture, showed a significantly lower clinical failure rate in patients undergoing ACL reconstruction and LET when compared to ACL reconstruction alone. ⁷