The anterolateral ligament of the knee: anatomy, biomechanics, and clinical implications

Anatomic reconstruction of the anterior cruciate ligament of the knee with or without reconstruction of the anterolateral ligament: A meta-analysis

PURPOSE

To systematically analyze the effectiveness between combined anterior cruciate ligament and anterolateral ligament reconstruction (ACL+ALLR) and isolated anterior cruciate ligament reconstruction (ACLR) for treatment of patients with injured ACL.

METHODS

We performed a systematic search in MEDLINE, EMBASE, PubMed, Web of Science, Cochrane databases, Chinese Biomedical Literature Database, CNKI, and Wanfang Data for all relevant studies. All statistical analysis was performed using Review Manager version 5.3.

RESULTS

A total of six articles with 460 study subjects were included, with 193 patients in ACL+ALL reconstruction group and 267 patients in ACL reconstruction group. The results of the meta-analysis showed that the ACL+ALL reconstruction group had significantly lower KT measured value (P < 0.00001), Lachman test positive-rate (P = 0.02), Pivot-shift test positive-rate (P < 0.00001) and graft rupture rate (P = 0.02) compared with the ACL reconstruction group. Higher IKDC score (P < 0.00001) and Lysholm score (P < 0.00001) were measured in ACL+ALL reconstruction group, while infection rate (P = 0.86) and other complications rate (P = 0.29) showed no significant differences between the two groups.

CONCLUSIONS

Anatomic reconstruction of the ACL of the knee with reconstruction of the ALL indicates better postoperative knee function and clinical outcomes compared with isolated ACL reconstruction. The infection rate and other complications rate showed no significant difference between two groups.

Anatomic and Histological Study of the Anterolateral Aspect of the Knee: A SANTI Group Investigation

Background:

The structure and function of the anterolateral aspect of the knee have been significantly debated, with renewed interest in this topic since the description of the anterolateral ligament (ALL).

Purpose:

To define and describe the distinct structures of the lateral knee and to correlate the macroscopic and histologic anatomic features.

Study Design:

Descriptive laboratory study.

Methods:

Twelve fresh-frozen human cadavers were used for anatomic analysis. In the left knee, a layer-by-layer dissection and macroscopic analysis were performed. In the right knee, an en bloc specimen was obtained encompassing an area from the Gerdy tubercle to the posterior fibular head and extending proximally from the anterior aspect to the posterior aspect of the lateral femoral epicondyle. The en bloc resection was then frozen, sliced at the level of the joint line, and reviewed by a musculoskeletal pathologist.

Results:

Macroscopically, the lateral knee has 4 main layers overlying the capsule of the knee: the aponeurotic layer, the superficial layer including the iliotibial band (ITB), the deep fascial layer, and the ALL. Histologically, 8 of 12 specimens demonstrated 4 consistent, distinct structures: the ITB, the ALL, the lateral collateral ligament, and the meniscus.

Conclusion:

The lateral knee has a complex orientation of layers and fibers. The ALL is a distinct structure from the ITB and is synonymous to the previously described capsulo-osseous layer of the ITB.

Clinical Relevance:

Increasingly, lateral extra-articular procedures are performed at the time of anterior cruciate ligament reconstruction. Understanding the anatomic features of the anterolateral aspect of the knee is necessary to understand the biomechanics and function of the structures present and allows surgeons to attempt to replicate those anatomic characteristics when performing extra-articular reconstruction.

Clinical outcomes of extra-articular tenodesis/anterolateral reconstruction in the ACL injured knee

PURPOSE

The role of concomitant extra-articular procedures in improving the outcome of ACL reconstruction has experienced a recent resurgence in interest. The aim of this article is to highlight the differences in philosophies and outcomes of historical lateral extra-articular tenodesis (LET) and contemporary, anterolateral reconstruction.

METHODS

A narrative review was performed using PubMed/MEDLINE using the keywords "lateral extra-articular tenodesis" and "anterolateral ligament reconstruction".

RESULTS

Results of search strategy: Thirty-seven studies [13 reporting clinical outcomes of isolated LET in ACL deficient knees and 24 comparing isolated anterior cruciate ligament reconstruction (ACLR) with ACLR + LET] and 1 study on anterolateral ligament (ALL) reconstruction were identified as relevant and included in the review. Results of literature review: Isolated extra-articular reconstructions are rarely performed in contemporary practice. They are associated with a high rate of persistent anterior instability and early degenerative change. Combined ACL reconstruction and lateral extra-articular tenodeses results in a significant reduction in the prevalence of residual pivot shift, but the majority of the studies do not demonstrate any significant difference with respect to patient-reported outcome measures and return to sport. Although several authors report a trend towards decreased graft rupture rates, significant differences were not demonstrated in most studies. In a single clinical study, combined anatomic ACL and anterolateral ligament reconstruction was reported to be associated with a threefold reduction in graft rupture rates and improved return to sport compared to isolated ACL graft choices.

CONCLUSIONS

Historically performed, combined ACL reconstruction and lateral extra-articular tenodeses are associated with improved knee kinematics. Although trends towards decreased graft rupture rates are reported by several authors, the majority did not demonstrate a significant difference, likely as a result of small and underpowered studies using post-operative immobilisation and delayed rehabilitation protocols. More recently, combined ACLR and ALL reconstruction has been shown to be associated with significant improvements in graft failure and return to sport rates when compared to isolated ACLR. However, these results are from a single clinical series with only medium-term follow-up.

LEVEL OF EVIDENCE

IV.

Anterolateral Ligament (ALL) — Myth or Reality?

Although the anterolateral ligament (ALL) was described a long time ago, recent research shows a lot of interest regarding this structure. There is a high variability concerning its anatomy, especially its capsular/extracapsular situation and insertion sites. There is also some controversy about its ligamentous structure. It seems that it has a biomechanical role in restricting anterior tibial translation and internal rotation. The ALL complex seems to have a clinical significance, and a relationship with the pivot shift has been described. Although there are promising results recently, the surgical techniques of ALL reconstruction, in addition to anterior cruciate ligament reconstruction, have to be further investigated. A precise indication algorithm and patient selection criteria need to be established.