Lateral extra-articular augmentation techniques alongside anterior cruciate ligament reconstruction: comparison of semi-anatomical, anatomical and non-anatomical procedures
Year: 2025
Type: article
Abstract: INTRODUCTION Anterior cruciate ligament (ACL) rupture is one of the most common musculoskeletal injuries in young individuals,[1,2] with an eight times higher incidence observed among female athletes than male athletes.[3] Such an injury often leads to increased translational and rotational instability,[2] presenting orthopaedic surgeons with the dilemma of whether to reconstruct the anterolateral complex. Numerous studies have reported on the persistence of knee instability after isolated ACL reconstruction (ACLr) in up to 20% of cases,[4] with a positive pivot shift test considered an important indicator of failed reconstruction.[5] Lateral extra-articular augmentation (LEA) techniques have gained popularity, as they provide additional stability to the anterolateral complex, addressing the persistent rotational knee instability.[2,6] Lateral extra-articular tenodesis (LET), anterolateral ligament reconstruction (ALLr) and ‘over-the-top’ ACLr with lateral plasty are three of the most commonly employed LEA techniques [Figure 1], due to their potential to more effectively restore knee joint kinematics.[7] Several biomechanical studies have shown the superiority of combined ACLr with an LEA technique, specifically when ACL rupture co-occurs with lesions to the anterolateral complex,[8] such as iliotibial band (ITB), anterolateral ligament (ALL), anterolateral capsule and lateral meniscus. In addition, performing an LEA technique in primary ACLr provides better rotational stability and improves clinical outcomes.[9] Currently, the literature supports that combined procedures, LEA and ACLr, can significantly reduce the risk of graft re-rupture[3,7] by three times.[6]Figure 1: Illustration of three lateral extra-articular augmentation techniques on a right knee: (a) modified Lemaire lateral extra-articular tenodesis (LET);[ 13 ] (b) anterolateral ligament (ALL) reconstruction;[ 18 ] and (c) over-the-top anterolateral ligament reconstruction (ACLr) (with lateral plasty) alongside anterior cruciate ligament (ACL) reconstruction.[ 23 ] G: gracilis, ITB: iliotibial band, LCL: lateral collateral ligament, LIMS: lateral intermuscular septum, LP: lateral plasty, ST: semitendinosusThe complex nature of the anterolateral structures of the knee joint forms a functional unit that contributes significantly to rotational stability.[8] Persistent rotational instability and grade 3 pivot shift test may be indicative of lesions of the anterolateral complex and suggest the need for adding lateral augmentation during ACL.[7] Recent literature recommends using the LEA technique only in selected cases that meet specific criteria, such as joint hyperlaxity, revision ACLr, age below 20 years, elite athletes and participation in pivoting sports.[7,9] Currently, the question remains: which is the most suitable LEA technique to enhance stability and restore knee kinematics while minimising the risk of complications, such as increased pain, prolonged rehabilitation period and lateral compartment over-constraint leading to osteoarthritis. LATERAL EXTRA-ARTICULAR TENODESIS Since Lemaire’s first description of LET in 1967 to address anterolateral complex deficiency, numerous studies have described various modified Lemaire techniques.[10-12] These typically involve harvesting a strip from the middle of the iliotibial band (ITB) while preserving its distal attachment to Gerdy’s tubercle. The proximal end of the iliotibial strip is then routed deep to and beneath the lateral collateral ligament (LCL). It is subsequently fixed proximal and posterior to the LCL origin — either in a bone tunnel with an interference screw,[10] with a suture anchor,[11] using common suspensory femoral fixation,[12] or by suturing it to the lateral intermuscular septum. Mahmoud et al.[13] described a technique for LET using a strip of ITB. During the procedure, a 12- to 15-cm strip of ITB is detached proximally, excluding the posterior curved fibres. The strip of ITB is passed under the LCL, through the lateral distal intermuscular septum from posterior to anterior, and fixed adjacent to the femur. The graft of ITB is sutured to itself at physiological tension, with the foot in neutral rotation and the knee in 50° of flexion. The main advantage of this technique is its simplicity, as it can be easily performed by surgeons who already perform ACLr and LET.[4,13] Moreover, no additional implant, such as anchor, stapler or screw, is required to fix the iliotibial graft, thus keeping cost relatively low [Table 1].[13] Of note, this technique reduces the risk of tunnel coalition when performed with ACLr and does not require extra surgical steps that could increase the complexity of the described technique.[4,13] However, failure to close the ITB defect may result in muscle herniation and persistent pain in the donor site [Table 1].[4] The LET procedure, when performed in combination with ACLr, alters lateral compartment pressures, increasing the risk of over-constraining the lateral tibiofemoral compartment, which could potentially lead to osteoarthritis.[8,14] Biomechanical studies found that a minimal LET graft tension of 20 N is adequate to prevent over-constraint of the lateral compartment and restore normal knee kinematics.[14,15]Table 1: Advantages and disadvantages of three lateral extra-articular augmentation techniques.Anterolateral ligament reconstruction In 1879, Paul Segond described a cortical avulsion fracture of the proximal tibia, located just distal to the lateral tibial plateau at the site of insertion of the middle third of the lateral capsular ligament.[6] Vieira et al.[16] first used the term ‘anterolateral ligament’ of the knee in 2007, describing it as an anatomical fibro-osseous part of ITB. Interestingly, in 2013, Claes et al.[17] published a detailed anatomical description of ALL as a distinct ligamentous structure on the anterolateral aspect of the knee joint. To date, several studies have been conducted and different techniques combining ACL and ALL reconstruction have been proposed to decrease rotational stability and reduce positive pivot shift test.[2,6,7,18] Sonnery-Cottet et al.[18] described a combined ACL and ALL reconstruction technique using hamstring tendon autograft and maintaining the semitendinosus insertion. In this technique, the ACL graft is formed from a tripled semitendinosus tendon and a single strand of gracilis tendon. The femoral tunnel is placed in an anatomical intra-articular location, with the exit point in the femur just posterior and proximal to the lateral epicondyle. The additional length of the single strand of gracilis exits the femoral tunnel at the anatomical origin of ALL, and is routed through a tibial tunnel, under the ITB and back to the femoral origin [Figure 1].[6,18] The potential advantages of ALLr include the improved biomechanical function of the knee due to the improved isometric property afforded by the anatomical tunnel placement in both the femur and tibia.[18,19] This double-bundle ALLr, with an inverted Y-shaped configuration, mimics the triangular shape of the native ALL with its narrow and broad femoral and tibial attachments, respectively.[18] With this technique, the Kaplan fibres of ITB are preserved and peroneal nerve injury can be avoided [Table 1].[20,21] In addition, to reduce the risk of over-constraint and non-anatomical rotation of the lateral compartment, the ALL graft is routed percutaneously under the ITB and above the LCL.[18] However, it is important to exercise caution, as the tibial sockets are very close together, and there is always a risk of bone bridge fracture between them. Moreover, as the tibial attachment of the semitendinosus is preserved, there is a risk of injury during tibial tunnel drilling [Table 1].[6] ‘Over-the-top’ ACLr with lateral plasty The ‘over-the-top’ technique, first described by Marshall et al.[22] in 1979, involves using the patellar and quadriceps tendons as a graft to reconstruct the ACL. In this technique, a strip of fascia lata is used to reinforce the primary ACLr. The strip is left attached distally, while the proximal part of the strip is placed ‘over the top’ of the lateral femoral condyle. Meanwhile, Marcacci et al.[23] performed a combined intra- and extra-articular arthroscopic ACLr using hamstring tendons. In this technique, semitendinosus and gracilis tendons are harvested and sutured together, leaving the distal insertion intact. After creating the tibial tunnel, the graft is passed through it and positioned in an ‘over-the-top’ manner, with a groove created in the posterolateral aspect of the femur. Then, the graft is fixed with two staples in the groove, while the remaining part of the graft is fixed distally to Gerdy’s tubercle, passing under the fascia and over the LCL [Figure 1].[23] The main advantage of this technique is the absence of a femoral tunnel, eliminating the risk of tunnel malposition and convergence during intra- and extra-articular reconstructions,[24] — recognised as the primary cause of surgical failure[24] and ACL revision surgery.[25] Additionally, this technique is cost effective, as only three staples are required for graft and lateral augmentation fixation at the femur and tibia.[24,25] However, despite its clear advantages, critics of the technique argue that it may increase graft stress and lead to failure, as it is a non-anatomical lateral augmentation method.[26] Additionally, the risk of symptomatic hardware is a concern — particularly due to graft fixation in the tibia and the use of a subcutaneous staple at a site just distal to Gerdy’s tubercle.[27,28] DISCUSSION This commentary aims to review possible advantages and disadvantages of a semi-anatomical LET, an anatomical ALLr and a non-anatomical ‘over-the-top’ lateral augmentation technique in the context of an ACLr. Presently, none of these techniques is without drawbacks. More than ever, the success of a procedure depends on the surgeon’s training and experience with the specific technique. The distinction between anatomical, semi-anatomical and non-anatomical lateral augmentation techniques lies in how the graft is placed on the femoral and tibial insertions. Mahmoud et al.[13] proposed a semi-anatomical lateral augmentation technique by keeping the femoral insertion of the native ALL, using an ITB graft and positioning it just proximal and posterior to the LCL, through the lateral intermuscular septum. The only part of this technique that cannot be changed is the preservation of the distal insertion of the ITB graft on Gerdy’s tubercle,[13] creating a semi-anatomical reconstruction of the native ALL. The literature supports the finding that ALL is a thin ligament that is distinct from the knee capsule, which has a femoral insertion just proximal and posterior to the lateral femoral epicondyle and a tibial attachment at the midpoint between Gerdy’s tubercle and fibular head.[29] Thus, it is clear that the technique by Sonnery-Cottet et al. attempts to reproduce the native anatomy of ALL and the normal kinematics of the knee joint. In contrast, the ‘over-the-top’ technique by Marcacci et al.,[23] seeks to restore the function of several lateral structures of the anterolateral complex, which contribute significantly to the rotational stability of the knee.[7,28] All three techniques are not free from complications, particularly the risk of over-constraining the lateral compartment mainly at 60° and 90° of knee flexion.[15,30] In addition, postoperative over-constraint may lead to gradual elongation of the graft, alterations in knee biomechanics and increase in contact forces within the joint that can accelerate joint degeneration.[31,32] The literature describes various ways to avoid over-constraint of the lateral compartment. Since LET provides the possibility of manually adjusting the tension of the ITB graft, biomechanical studies suggest that the flexion angle can be fixed at 30° to 70° of flexion, with neutral rotation of the foot and application of low tension of 20 N on the graft during femoral fixation.[15,33] Similarly, to minimise the risk of knee over-constraint during ALLr, the graft is always fixed in full extension and neutral rotation to respect its normal non-isometry.[6,34] In contrast, the ‘over-the-top’ lateral augmentation technique tends to over-constrain the knee at 0° to 60° of knee flexion, but not at 90°.[35] Zaffagnini et al.[36] proposed the use of the hamstring graft to perform lateral plasty without intersecting the iliotibial tract. This technique may avoid lateral overtightening, which can cause degenerative changes in the lateral compartment.[36] For reoperation, LEA techniques (both anatomical or non-anatomical) reduce the risk of ACL graft re-rupture and minimise the risk of reoperation by almost three times in high-risk population[37] while improving the rate of return to sport.[6] In a retrospective case–control study by Mahmoud et al.,[13] a 5% graft failure rate was found in patients who underwent primary ACLr (quadrupled semitendinosus–gracilis graft) combined with modified Lemaire LET using ITB, as compared to 11% in the ACLr group, over a mean follow-up period of 10 years. Although considered low, this graft failure rate is still higher than that for combined ACLr and ALLr (3.5%)[38] and ‘over-the-top’ technique plus lateral plasty (3.5%).[39] A possible explanation for the slightly higher failure rate could be due to the proximal dynamic type of fixation of ITB as a graft in the lateral intermuscular septum. However, Mahmoud et al.[13] believe that this technique of dynamic fixation overcomes the issue of over-constrained joint, which may be possible with techniques involving the use of staples and bone tunnels. Using an ALLr, Sonnery-Cottet et al.[38] reported a lower revision rate of 3.5% for ACLr as compared to isolated ACLr (17.4%) at over a long-term follow-up period of about 8.7 years. It is clear from the literature that LEA techniques offer a powerful tool to control rotation of the knee and drastically decrease the failure rate from 17.4%[38] to 3%.[39] Despite the well-established role of LEA techniques in minimising graft failure during ACLr with hamstrings autograft,[1,13,24,28,38,39] there remains a lack of in-depth research on the role of quadriceps tendon and bone–patellar tendon–bone as an ACL graft in graft failure. Recent studies have demonstrated that the use of different types of graft for primary and revision ACLr, such as bone–patellar tendon–bone[40] and soft tissue quadriceps tendon graft,[41] performed with a concomitant LET using a modified Lemaire technique can significantly reduce graft failure rate. Similarly, data presented by Alessio-Mazzola et al.[42] showed no graft failure among patients with a combined autologous bone–patellar tendon–bone autograft for ACL graft and LET procedure. However, the mean reported follow-up period from these studies ranged from 2 to 4 years,[40-42] indicating a short postoperative period, which is not truly predictive of worse postoperative outcomes. Despite overall positive effects, it is difficult to draw definitive conclusions regarding the superiority of quadriceps and patellar tendon grafts in reducing reoperation rates due to the short postoperative follow-up periods of these studies. Grassi et al.[39] analysed the data of 267 patients who underwent ACLr with an ‘over-the-top’ surgical technique using single-strand semitendinosus and gracilis tendon with their tibial attachments preserved. They found a revision rate of 1.1% at 2 years and 3.7% at 10 years follow-up. These rates are better than the reported rates after isolated ACLr with hamstrings and bone–patellar tendon–bone autografts.[1,38,42] In addition, these rates are similar to those reported after ALLr (3.5%)[38] and slightly better than those observed with modified Lemaire LET (5%).[13] In a recently published systematic review, Sarraj et al.[26] reported that ‘over-the-top’ ACLr is an efficacious procedure in both primary and revision cases with outcomes similar to standard modern techniques. Likewise, this review found that a re-rupture rate of 3.7% among 453 patients with a mean follow-up period of 4.3 years. However, the ‘over-the-top’ technique is not among the commonly used lateral extra-articular procedures,[24] despite its rising popularity, especially among growing patients with an immature skeleton.[43] CONCLUSION Although several techniques for LEA have been introduced, the ideal surgical technique for combined ACL and anterolateral structures reconstruction has not been established. Currently, there is no direct comparison in the literature between semi-anatomical, anatomical and non-anatomical LEA techniques. Each reported type of LEA technique used alongside ACLr has its own role. There is no perfect technique and each procedure has its pros and cons. Therefore, the choice of technique depends on the surgeon’s preference and expertise. The debate regarding which technique is best can only be answered through future comparative studies with long-term follow-up. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Source: Singapore Medical Journal
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4411141131