Historical perspective on the "discovery" of the anterolateral ligament of the knee

Isolated ACL Reconstruction Versus Combined ACL and Anterolateral Ligament Reconstruction: Functional Outcomes, Return to Sport, and Survivorship: An Updated Meta-analysis of Comparative Studies

BACKGROUND

Failure, persistent knee instability, and reinjury rates after anterior cruciate ligament (ACL) reconstruction are still concerns. Biomechanical investigations have highlighted the role of the anterolateral ligament (ALL) as a crucial knee stabilizer, and clinical outcomes after combined ACL and ALL reconstruction appear to indicate the success of the procedure.

PURPOSE

To compare the functional outcomes, return-to-sport (RTS) rate, and complications between combined ACL and ALL reconstruction and isolated ACL reconstruction.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The PubMed/MEDLINE, Scopus, and Cochrane Central databases were used to search keywords, and a total of 16 studies were included. The data extracted for quantitative analysis included the Tegner activity scale score, Lysholm knee score, International Knee Documentation Committee (IKDC) score, laxity measured using the KT-1000 knee arthrometer, number and types of complications, RTS rate, and survival rate. Random- and fixed-effects models were used for the meta-analysis of pooled mean differences and odds ratios.

RESULTS

A total of 2329 patients were identified, 1116 of whom underwent combined ACL and ALL reconstruction and 1213 of whom underwent isolated ACL reconstruction. The mean ages were 25.4 ± 7.2 years and 26.5 ± 7.8 years for the combined ACL and ALL reconstruction and isolated ACL reconstruction groups, respectively. The mean follow-ups were 40.3 ± 21.4 months and 42.5 ± 21.6 months, respectively. Comparable Tegner activity scale (P = .16), Lysholm knee (P = .13), and IKDC (P = .83) scores were found between groups. Significantly greater postoperative knee laxity was found in the isolated ACL reconstruction group (mean difference, -0.44; 95% CI, -0.85 to -0.04; P = .03). The combined ACL and ALL reconstruction group showed a significantly lower rate of graft failure (odds ratio [OR], 0.37; 95% CI, 0.18-0.77; P = .008), a higher RTS rate (OR, 1.41; 95% CI, 1.11-1.80; P = .005), and a higher survival rate (OR, 2.94; 95% CI, 1.97-4.37; P < .001).

CONCLUSION

Compared with isolated ACL reconstruction, combined ACL and ALL reconstruction yielded comparable functional outcomes but significantly less residual knee laxity and a lower graft failure rate. Patients who underwent combined ACL and ALL reconstruction also had higher RTS and survival rates.

Evaluation of anterolateral ligament healing in patients with anterior cruciate ligament injury without anterior cruciate ligament reconstruction and its relationship with clinical examination tests

PURPOSE

This study radiologically investigated the potential of preoperative recovery of the anterolateral ligament (ALL) in patients who did not undergo anterior cruciate ligament reconstruction (ACLR) surgery in the early stages despite surgical indication. The secondary aim was to investigate the relationship between ALL injuries in magnetic resonance imaging (MRI) and the results of Lachman and pivot shift tests performed preoperatively and postoperatively under anaesthesia among patients who underwent ACLR in acute and chronic stages.

METHODS

The study examined 100 patients aged 19-51 years who underwent anatomic single bundle ACLR using hamstring autografts for the ACL. Based on the time between the injury and ACLR, they were divided into acute (≤6 months) and chronic (>6 months) groups. The chronic group had three subgroups of ACLR times: 7-12, 13-24 and >24 months. Complete recovery was defined as a change from grade B or C upon injury to grade A before surgery according to the Muramatsu MRI classification. The relationship between preoperative and postoperative Lachman grades and pivot shifting test results and the degree of ALL injury was evaluated.

RESULTS

In the chronic group, 19/61 patients (31.1%) had preoperative grade A, and 4/61 patients (6.5%) had grade A at the time of injury. In the acute group, 22/29 patients with grades B and C (76%) had grade 3 preoperative pivot shifting. In the acute group, grades 1 and 2 were more common in patients with grades B and C (10/29, 35%) than grade A (0/10, 0.0%).

CONCLUSION

The improvement rate was 24.6% among patients who did not receive ACLR in the acute phase and underwent ACLR in the chronic phase. In the acute group, the degree of ALL damage was related to the pivot shift results. However, the results in the chronic phase were not associated with the degree of injury.

LEVEL OF EVIDENCE

Level IV.

Biomechanical Evaluation of Anterolateral Ligament Repair Augmented with Internal Brace

Injuries to the anterolateral ligament (ALL) of the knee are commonly associated with anterior cruciate ligament (ACL) ruptures. Biomechanical studies have demonstrated conflicting results with regard to the role of the ALL in limiting tibial internal rotation. Clinically, residual pivot shift following ACL reconstruction has been reported to occur up to 25% and has been correlated with poor outcomes. As such, surgical techniques have been developed to enhance rotational stability. Recent biomechanical studies have demonstrated restoration of internal rotational control following ALL reconstruction. The purpose of our study was to understand the biomechanical effects of ACL reconstruction with an ALL internal brace augmentation. We hypothesized that (1) sectioning of the ALL while preserving other lateral extra-articular structures would lead to significant internal rotation laxity and gap formation and (2) ALL repair with internal brace augmentation would lead to reduction in internal rotation instability and gap formation. In total, 10 fresh-frozen cadaveric knees were thawed and biomechanically tested in internal rotation for 10 cycles of normal physiologic torque in the intact, ACL-deficient, ACL/ALL-deficient, ACL-reconstructed, and ALL-repaired conditions. Each condition was tested at 30, 60, and 90 degrees of flexion. Following the final ALL-repaired condition, specimens were additionally subjected to a final internal rotation to failure at 1 degree at the last-tested degree of flexion. Kinematic measurements of angle and linear gap between the femur and tibia were calculated in addition to torsional stiffness and failure torque. As hypothesized, ALL repair with internal brace augmentation significantly reduced internal rotation angular motion and gap formation at flexion angles greater than 30 degrees. Additionally, ALL sectioning produced nonsignificant increases in internal rotation laxity and gap formation compared with ACL-deficient and ACL-reconstructed states, which did not support our other hypothesis.

A Review of Current Concepts of the Anterolateral Complex of the Knee

The anterolateral complex (ALC) of the knee has gained increased interest over the last decades due to the high revision rates of anterior cruciate ligament reconstruction (ACLR). Furthermore, in patients with an ACL tear, the injury of at least one of the ALC's anatomic structures has been shown to be significantly higher, thus affecting its secondary stabilizing role at the knee joint. As such, ACLR augmentation techniques, that embrace the ALC, have been proposed recently, and indications for these procedures are still evolving. This review aims to present and discuss the most current anatomical, biomechanical, and imaging data, current reconstruction techniques, and the clinical results of ALC reconstruction.

Increased lateral femoral condyle ratio is associated with greater risk of ALC injury in non-contact anterior cruciate ligament injury

PURPOSE

To examine whether increased lateral femoral condyle ratio (LFCR) correlates with increased risk of Anterior cruciate ligament (ACL) injury (1) and to evaluate the relationship between the LFCR and anterolateral complex (ALC) injury in non-contact ACL torn knees (2).

METHODS

Six hundred and seventy-two patients who underwent ACL reconstruction surgery between 2013 and 2019 were retrospectively reviewed, and 120 patients were finally included in the study. Forty patients (ACL + ALC injury) were included in the study group, while forty patients with isolated ACL injury (isolated ACL injury group) and 40 patients who suffered from meniscal tear without ACL or ALC injury were matched in a 1:1 fashion by age, sex, and BMI to the study group (ACL + ALC injury). The LFCR was measured on standard lateral radiographs in a blinded fashion. The differences between the three groups were analyzed by ANOVA. A ROC (Receiver Operating Characteristic) curve was produced to determine risk of ACL injury and risk of concomitant ALC injury in non-contact ACL injury.

RESULTS

The mean LFCR was 71.9% ± 3.1% in the ACL + ALC injury group, 68.4% ± 3.2% in the isolated ACL injury group, and 66.8% ± 2.6% in the control group (patients who suffered from meniscal tear without ACL or ALC injury). Significantly greater LFCR was found in the ACL + ALC injury group than that in the isolated ACL injury group (p < 0.017). Greater LFCR was additionally confirmed in the ACL injury group as compared to the control group (p < 0.05). ROC curve analysis demonstrated that LFCR > 68.3% was predictive for an increased risk of ACL injury in the entire cohort. LFCR > 69.4% was predictive for an increased risk of ALC injury in non-contact ACL ruptured patients.

CONCLUSION

Increased LFCR was found to be associated with greater risk of ALC injury in non-contact ACL ruptured patients. Additionally, increased LFCR was further confirmed to be correlated with increased risk of ACL injury in an Asian population. The data from this study may help recognize patients undergoing ACL reconstruction that could benefit from additional extra-articular tenodesis.

LEVEL OF EVIDENCE

III.

The anterolateral ligament of the knee joint: a review of the anatomy, biomechanics, and anterolateral ligament surgery

Residual knee instability and low rates of return to previous sport are major concerns after anterior cruciate ligament (ACL) reconstruction. To improve outcomes, surgical methods, such as the anatomical single-bundle technique or the double-bundle technique, were developed. However, these reconstruction techniques failed to adequately overcome these problems, and, therefore, new potential answers continue to be of great interest. Based on recent anatomical and biomechanical studies emphasizing the role of the anterolateral ligament (ALL) in rotational stability, novel surgical methods including ALL reconstruction and anterolateral tenodesis have been introduced with the possibility of resolving residual instability after ACL reconstruction. However, there is still little consensus on many aspects of the ALL, including: several anatomical issues, appropriate indications for ALL surgery, and the optimal surgical method and graft choice for reconstruction surgery. Therefore, further studies are necessary to advance our knowledge of the ALL and its contribution to knee stability.

The anterolateral ligament of the knee and the lateral meniscotibial ligament - Anatomical phantom versus constant structure within the anterolateral complex

BACKGROUND

Concerning the ongoing controversy about the existence and nature of the anterolateral ligament (ALL) of the knee joint, we reinvestigated the formation of the anterolateral part of its fibrous capsule in anatomic specimens. Furthermore, we wanted to clarify if the lateral meniscus has established a constant anchoring to the lateral tibial condyle via a lateral meniscotibial ligament (lmtl).

METHODS

Forty paired embalmed lower extremities taken from 20 human body donors (15 men and five women) underwent exact macroscopic dissection. For the detailed evaluation of the lmtl, additionally 12 specially dissected joint specimens were used. In two of these specimens, the lmtl underwent further histological examination.

RESULTS

In all specimens, the anterolateral part of the knee joint fibrous capsule was established by the iliotibial tract and the anterior arm of the aponeurosis of the biceps femoris muscle. According to their close connection and the fact that the anterolateral part of the fibrous capsule is exclusively assembled by these two aponeuroses, they do not leave any space for a distinct ALL connecting the lateral femoral epicondyle and the lateral tibial condyle. The constantly present lmtl was identified as a flat, rectangular bundle of collagen and also elastic fibers reinforcing the inner aspect of the fibrous capsule. Following an oblique direction, it connected the lateral face of the lateral meniscus with the superolateral margin of the lateral tibial condyle. The lmtl measured, on average, 17.1mm in longitudinal and 13mm in anteroposterior direction.

CONCLUSION

Our results show that there is no evidence for the existence of an ALL in human knee joints. It is represented either by the iliotibial tract or - most likely - by the anterior arm of the short head of the biceps femoris muscle. On the other hand, the lmtl was found to be a constantly present structure.

The Origin of the Knee Anterolateral Ligament Discovery: A Translation of Segond's Original Work With Commentary

Paul Segond was a French surgeon who was in practice at the end of the 19th century. A prodigious anatomist, scientist, and surgeon in his day, he is best known for his treatise on the origin of traumatic hemarthrosis of the knee following injury. In this detailed description of the anatomy of the anterolateral aspect of the knee, he describes "a pearly, resistant, fibrous band that is placed under extreme tension when the knee is forcefully rotated internally," which has more recently been described as the anterolateral ligament or a capsular thickening contributing to the anterolateral complex of the knee. His work goes on to speculate about the role of this structure in controlling internal rotation of the knee. The original study was published in French in 1879. Although this work is widely cited, one must question whether many of the citing authors have actually had the opportunity to read it. As such, we sought to unlock this treasure by translating the original study into English and exposing this illuminating, forward-thinking and historical tour de force to the broader orthopaedic community.

Editorial Commentary: Knee Anterolateral Ligament Bashing-Why So Much Negativity?

Articles on the anterolateral ligament have generated lots of discussion, but a worldwide consensus has been recently reached: the anterolateral ligament exists. Cadaver studies on a small number of subjects should not be used to draw conclusions as they do not replicate real life. We place our faith in clinical studies with a large number of patients as they capture the variability encountered in our practices. This is the true test of a scientific concept.

Editorial Commentary: Looking Outside the Box With Ultrasound in an Anterior Cruciate Ligament-Deficient Knee: Welcome to Surgery 2.0

Perspectives on the anterolateral ligament have changed greatly since the first articles were published that cast doubt on the existence of this structure. The current debate is centered on how to best analyze it. Surgeons are increasingly focusing on the knee's secondary restraints. It is important to understand that magnetic resonance imaging is not the only imaging modality available to us.

Current Concepts of the Anterolateral Ligament of the Knee: Anatomy, Biomechanics, and Reconstruction

In 1879, Paul Segond described an avulsion fracture (now known as a Segond fracture) at the anterolateral proximal tibia with the presence of a fibrous band at the location of this fracture. Although references to this ligament were occasionally made in the anatomy literature after Segond's discovery, it was not until 2012 that Vincent et al named this ligament what we know it as today, the anterolateral ligament (ALL) of the knee. The ALL originates near the lateral epicondyle of the distal femur and inserts on the proximal tibia near Gerdy's tubercle. The ALL exists as a ligamentous structure that comes under tension during internal rotation at 30°. In the majority of specimens, the ALL can be visualized as a ligamentous structure, whereas in some cases it may only be palpated as bundles of more tense capsular tissue when internal rotation is applied. Biomechanical studies have shown that the ALL functions as a secondary stabilizer to the anterior cruciate ligament (ACL) in resisting anterior tibial translation and internal tibial rotation. These biomechanical studies indicate that concurrent reconstruction of the ACL and ALL results in significantly reduced internal rotation and axial plane tibial translation compared with isolated ACL reconstruction (ACLR) in the presence of ALL deficiency. Clinically, a variety of techniques are available for ALL reconstruction (ALLR). Current graft options include the iliotibial (IT) band, gracilis tendon autograft or allograft, and semitendinosus tendon autograft or allograft. Fixation angle also varies between studies from full knee extension to 60° to 90° of flexion. To date, only 1 modern study has described the clinical outcomes of concomitant ALLR and ACLR: a case series of 92 patients with a minimum 2-year follow-up. Further studies are necessary to define the ideal graft type, location of fixation, and fixation angle for ALLR. Future studies also must be designed in a prospective comparative manner to compare the clinical outcomes of patients undergoing ACLR with ALL reconstruction versus without ALL reconstruction. By discovering the true effect of the ALL, investigators can elucidate the importance of ALLR in the setting of an ACL tear.