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Editorial Commentary: Nonanatomic Lateral Extra-Articular Procedures Performed at the Time of Anterior Cruciate Ligament Reconstruction Risk Overconstraint: Anatomic Anterolateral Ligament Reconstruction Does Not
Isolated anterior cruciate ligament reconstruction is associated with a risk of graft rupture that is more than 5-fold higher than that of combined anterior cruciate ligament–anterolateral ligament (ALL) reconstruction at a mean follow-up of greater than 100 months. However, biomechanical and clinical studies report that overconstraint is a concern with nonanatomic lateral-sided reconstruction. In fact, the normal biomechanics of the native ALL are anisometric. The ligament is tight in extension (providing rotational control) and slack in flexion (allowing physiological internal rotation). The ALL femoral attachment is proximal and posterior to the lateral epicondyle. The tibial tunnel or tunnels are located anterior to the fibular head and posterior to the Gerdy tubercle. An ALL graft must lie deep to the iliotibial band and superficial to the lateral collateral ligament. Fixation is performed in extension and neutral rotation. A single- or double-strand technique may be used. Surgeons performing lateral extra-articular procedures must understand the technical pitfalls that can lead to overconstraint and must seek to avoid them. Overconstraint can occur for a number of reasons, including the use of nonanatomic reconstruction and technical errors in tensioning, fixation angle, and tunnel positioning.
Lateral extra-articular procedures performed at the time of anterior cruciate ligament (ACL) reconstruction are increasingly popular. A plethora of new techniques with variable fixation angles and tunnel positions have been described, and there is ongoing debate regarding which technique is optimal. I congratulate Xu, Ye, Han, Xu, Zhao, and Dong
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
for their elegant study entitled “Anterolateral Structure Reconstructions With Different Tibial Attachment Sites Similarly Improve Tibiofemoral Kinematics and Result in Different Graft Force in Treating Knee Anterolateral Instability.” They report that anterior, middle, and posterior tibial attachment sites all similarly restored knee laxity close to the native state but also that all reconstructions were associated with some degree of overconstraint. These findings are of great value in highlighting some important potential pitfalls in lateral extra-articular reconstruction.
In my opinion, the most important message from the study by Xu et al.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
is that nonanatomic lateral extra-articular procedures risk overconstraint. Indeed, it is not clear from the current article exactly what structure the authors intended to reconstruct, but in a recent letter to the editor regarding a different study from the same institution,
the authors reported that their augmentation procedure “was based on the concept of the rotatory functional restoration, neglecting the precise anatomy of the ALL [anterolateral ligament] or ALC [anterolateral complex].”
I disagree with this statement on the basis that there are numerous comparative studies reporting significant benefits of combined ACL-ALL reconstruction
Anterolateral ligament reconstruction is associated with significantly reduced ACL graft rupture rates at a minimum follow-up of 2 years: A prospective comparative study of 502 patients from the SANTI Study Group.
Risk of graft rupture after adding a lateral extra-articular procedure at the time of ACL reconstruction: A retrospective comparative study of elite alpine skiers from the French National Team.
Clinical outcomes of isolated revision anterior cruciate ligament reconstruction or in combination with anatomic anterolateral ligament reconstruction.
Combined reconstruction of the anterolateral ligament in patients with anterior cruciate ligament injury and ligamentous hyperlaxity leads to better clinical stability and a lower failure rate than isolated anterior cruciate ligament reconstruction.
Epidemiological evaluation of meniscal ramp lesions in 3214 anterior cruciate ligament-injured knees from the SANTI Study Group database: A risk factor analysis and study of secondary meniscectomy rates following 769 ramp repairs.
Anterolateral ligament reconstruction protects the repaired medial meniscus: A comparative study of 383 anterior cruciate ligament reconstructions from the SANTI Study Group with a minimum follow-up of 2 years.
). The SANTI (Scientific ACL Network International) Study Group has also recently shown that isolated ACL reconstruction is associated with a risk of graft rupture that is more than 5-fold higher than that of combined ACL-ALL reconstruction at a mean follow-up of greater than 100 months.
Long-term graft rupture rates after combined ACL and anterolateral ligament reconstruction versus isolated ACL reconstruction: A matched-pair analysis from the SANTI Study Group.
These consistent findings across a wealth of studies, including at long-term follow-up, provide confidence in the clinical effectiveness of combined ACL-ALL reconstruction. It is also noteworthy that among specific investigations of complications and reoperations, no cases of overconstraint were identified.
Combined ACL and anterolateral reconstruction is not associated with a higher risk of adverse outcomes: Preliminary results from the SANTI randomized controlled trial.
Reoperation rates after combined anterior cruciate ligament and anterolateral ligament reconstruction: A series of 548 patients from the SANTI Study Group with a minimum follow-up of 2 years.
These studies share several key characteristics that seem to be important in minimizing the risk of overconstraint:
1
They aim to reconstruct a specific anatomic structure (the ALL) with precise landmarks and known biomechanics.
2
A femoral attachment proximal and posterior to the lateral epicondyle is used.
3
The reconstruction lies deep to the iliotibial band and superficial to the lateral collateral ligament.
4
Fixation is performed in extension and neutral rotation.
5
A single- or double-strand technique is used, with the tibial tunnel or tunnels located anterior to the fibular head and posterior to the Gerdy tubercle.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
report that (based on the ALL anatomy) they have used a femoral position that is proximal and posterior to the lateral epicondyle, the laboratory photographs and illustrations show a location that is at the level of (not proximal to) and posterior to the lateral epicondyle (Fig 1). This point may seem pedantic, but it is important point because it likely explains a large proportion of the overconstraint observed in the current study. Of clinical relevance, this is also a pitfall to be aware of and avoid intraoperatively.
Fig 1Illustration of lateral extra-articular reconstruction evaluated by Xu et al.,
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
revealing a femoral tunnel at the level of (not proximal to) and posterior to the lateral epicondyle. Reprinted with permission from Elsevier. (LCL, lateral collateral ligament; Ta, anterior tibial attachment; Tm, middle tibial attachment; Tp, posterior tibial attachment.)
There is a clear consensus that the normal biomechanics of the native ALL are anisometric and that its femoral attachment is proximal and posterior to the lateral epicondyle.
For a reconstruction to replicate this anisometry, an anatomic femoral position that is proximal and posterior to the lateral epicondyle is required (Fig 2). In a previous surgical technique note, we provided a video specifically highlighting the consequences of tunnel malposition during ALL reconstruction.
We showed that selecting a femoral attachment site at the level of the lateral epicondyle restricts internal rotation during knee flexion and therefore causes overconstraint.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
who also showed that overconstraint (less tibial anterolateral translation than the native state on simulated pivot shift) occurred with their chosen femoral position, regardless of which tibial tunnel position was used. Furthermore, the authors reported that these findings were most pronounced at 45° of flexion,
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
Fig 2Intraoperative photograph of lateral aspect of right knee. A surgical marking pen has been used to highlight the lateral collateral ligament and the lateral epicondyle. The femoral guide is positioned so that an outside-in wire enters the lateral cortex at the anatomic footprint of the anterolateral ligament, which is proximal and posterior to the lateral epicondyle.
(Reproduced with permission from Saithna A, Thaunat M, Delaloye JR, Ouanezar H, Fayard JM, Sonnery-Cottet B. Combined ACL and anterolateral ligament reconstruction. JBJS Essent Surg Tech 2018;8:e2.)
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
showed that all positions were able to control the rotatory instability that resulted from sectioning of the anterolateral structures but found that each location provided a different degree of control and resulted in different degrees of loading during the pivot shift. These results are consistent with those of our previous studies, which showed that altering the tibial tunnel position can significantly alter control of knee rotation and translation but that the magnitude of the effect is dependent on the femoral tunnel position and knee flexion angle at fixation.
Technical considerations in lateral extra-articular reconstruction coupled with anterior cruciate ligament reconstruction: A simulation study evaluating the influence of surgical parameters on control of knee stability.
Regardless, a notable finding from Xu et al. was that the tibial attachment position anterior to Gerdy's tubercle was associated with the most overconstraint. This is a location that is inconsistent with the attachment sites for both ALL reconstruction and iliotibial band–based procedures such as the modified Lemaire procedure, and again, this should serve to highlight the point that nonanatomic reconstruction risks overconstraint.
Historically, there has been considerable concern about overconstraint, and it is one of the reasons why extra-articular procedures were widely abandoned in the 1980s. At that time, there was a tendency to perform fixation in flexion and external rotation and to immobilize knees postoperatively in full extension for prolonged periods, both of which could lead to knee stiffness. However, a systematic review of long-term studies has suggested that concerns about overconstraint may be unwarranted because it did not show an increased rate of osteoarthritis with lateral extra-articular procedures.
Combined anterior cruciate ligament reconstruction and lateral extra-articular tenodesis does not result in an increased rate of osteoarthritis: A systematic review and best evidence synthesis.
Regardless, it is not confirmed that these issues have been fully resolved in contemporary practice. Although it is clear that combined reconstruction with either an ALL reconstruction or modified Lemaire procedure can restore normal knee kinematics without overconstraining the knee,
it is my opinion that overconstraint is perhaps more likely with a modified Lemaire procedure (because it is nonanatomic and the knee is fixed in flexion) when compared with an ALL reconstruction (anatomic, with the knee fixed in extension, replicating the normal biomechanics and anisometry of the ALL); this is supported by several biomechanical studies
Different anterolateral procedures have variable impact on knee kinematics and stability when performed in combination with anterior cruciate ligament reconstruction.
Lateral tenodesis procedures increase lateral compartment pressures more than anterolateral ligament reconstruction, when performed in combination with ACL reconstruction: A pilot biomechanical study.
Anterolateral structure reconstruction similarly improves the stability and causes less overconstraint in anterior cruciate ligament-reconstructed knees compared with modified Lemaire lateral extra-articular tenodesis: A biomechanical study.
Double-bundle anterior cruciate ligament reconstruction with lateral extra-articular tenodesis is effective in restoring knee stability in a chronic, complex anterior cruciate ligament-injured knee model: A cadaveric biomechanical study.
However, the issue is clouded by the fact that we do not have a clear consensus on the definition of “overconstraint” and what degree of overconstraint is clinically important. Although it is reassuring that long-term studies have not shown an increased risk of osteoarthritis, this remains an area that requires further study.
A further important point to highlight is that Xu et al.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
report an original technique and coin the term “anterolateral structure reconstruction” to describe it. This is reflective of the recent publication of an abundance of newly described lateral extra-articular techniques. In my opinion, given the wealth of clinical data supporting existing techniques (including long-term data), there is little justification for using a technique that is not supported by robust clinical data. Furthermore, I recommend against the use of new nomenclature because it is well recognized that the orthopaedic community’s quest for consensus on this topic has been hampered by confusing and overlapping terminology. In fact, numerous terms, including “capsulo-osseous layer,” “short lateral ligament,” “anterior oblique band,” “anterior band of the lateral collateral ligament,” and “middle-third lateral capsular ligament,” have all been used variably and sometimes interchangeably. Furthermore, using established and agreed-upon nomenclature
helps to make clear exactly what anatomic structure is being reconstructed and, therefore, what its precise landmarks, expected biomechanics, and expected clinical outcomes are.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
on their insightful study, which has helped to highlight that the issue of overconstraint remains an important consideration in lateral extra-articular reconstruction. Overconstraint can occur for a number of reasons, including the use of nonanatomic reconstruction and technical errors in tensioning, fixation angle, and tunnel positioning. Furthermore, the biomechanics of soft-tissue grafts versus synthetic grafts (such as those used by Xu et al.) have not been fully elucidated, and it is not clear whether the latter are associated with a greater risk of overconstraint. I recommend that surgeons performing lateral extra-articular procedures understand the technical pitfalls that can lead to overconstraint and seek to avoid them.
Anterolateral structure reconstructions with different tibial attachment sites similarly improve tibiofemoral kinematics and result in different graft force in treating knee anterolateral instability.
Anterolateral ligament reconstruction is associated with significantly reduced ACL graft rupture rates at a minimum follow-up of 2 years: A prospective comparative study of 502 patients from the SANTI Study Group.
Risk of graft rupture after adding a lateral extra-articular procedure at the time of ACL reconstruction: A retrospective comparative study of elite alpine skiers from the French National Team.
Clinical outcomes of isolated revision anterior cruciate ligament reconstruction or in combination with anatomic anterolateral ligament reconstruction.
Combined reconstruction of the anterolateral ligament in patients with anterior cruciate ligament injury and ligamentous hyperlaxity leads to better clinical stability and a lower failure rate than isolated anterior cruciate ligament reconstruction.
Epidemiological evaluation of meniscal ramp lesions in 3214 anterior cruciate ligament-injured knees from the SANTI Study Group database: A risk factor analysis and study of secondary meniscectomy rates following 769 ramp repairs.
Anterolateral ligament reconstruction protects the repaired medial meniscus: A comparative study of 383 anterior cruciate ligament reconstructions from the SANTI Study Group with a minimum follow-up of 2 years.
Long-term graft rupture rates after combined ACL and anterolateral ligament reconstruction versus isolated ACL reconstruction: A matched-pair analysis from the SANTI Study Group.
Combined ACL and anterolateral reconstruction is not associated with a higher risk of adverse outcomes: Preliminary results from the SANTI randomized controlled trial.
Reoperation rates after combined anterior cruciate ligament and anterolateral ligament reconstruction: A series of 548 patients from the SANTI Study Group with a minimum follow-up of 2 years.
Technical considerations in lateral extra-articular reconstruction coupled with anterior cruciate ligament reconstruction: A simulation study evaluating the influence of surgical parameters on control of knee stability.
Combined anterior cruciate ligament reconstruction and lateral extra-articular tenodesis does not result in an increased rate of osteoarthritis: A systematic review and best evidence synthesis.
Different anterolateral procedures have variable impact on knee kinematics and stability when performed in combination with anterior cruciate ligament reconstruction.
Lateral tenodesis procedures increase lateral compartment pressures more than anterolateral ligament reconstruction, when performed in combination with ACL reconstruction: A pilot biomechanical study.
Anterolateral structure reconstruction similarly improves the stability and causes less overconstraint in anterior cruciate ligament-reconstructed knees compared with modified Lemaire lateral extra-articular tenodesis: A biomechanical study.
Double-bundle anterior cruciate ligament reconstruction with lateral extra-articular tenodesis is effective in restoring knee stability in a chronic, complex anterior cruciate ligament-injured knee model: A cadaveric biomechanical study.
The author reports the following potential conflicts of interest or sources of funding: A.S. is a consultant for Arthrex and receives travel/accommodation/meeting expenses from AANA, outside the submitted work. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
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