Identification of Normal and Injured Anterolateral Ligaments of the Knee: A Systematic Review of Magnetic Resonance Imaging Studies

Demystifying the "Dark Side of the Knee": An Update on Imaging of the Posterolateral Corner

The posterolateral corner (PLC) of the knee is a complex anatomical-functional unit that includes ligamentous and tendinous structures that are crucial for joint stability. This review discusses the intricate anatomy, biomechanics, and imaging modalities, as well as the current challenges in diagnosing PLC injuries, with an emphasis on magnetic resonance imaging (MRI). Recognizing the normal MRI anatomy is critical in identifying abnormalities and guiding effective treatment strategies. Identification of the smaller structures of the PLC, traditionally difficult to depict on imaging, may not be necessary to diagnose a clinically significant PLC injury. Injuries to the PLC, often associated with cruciate ligament tears, should be promptly identified because failure to recognize them may result in persistent instability, secondary osteoarthritis, and cruciate graft failure.

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.

[Magnetic resonance imaging of the knee joint : What does the orthopedic surgeon expect from the radiologist?]

Magnet resonance imaging (MRI) offers a precise visualization of structural changes with high sensitivity and specificity. However, not all these soft tissue damages or bony lesions are clinically relevant or require treatment. Therefore, it is important to provide the radiologist with a specific clinical request when asking for an MRI examination of the knee. In this article, all important anatomical structures of the knee joint will be addressed with emphasis on the relevant questions for the radiologist. Based on the clinical examination, the MRI provides information about the damage of anatomical structures. This information is of utmost importance for therapeutic decision-making in order to allow an adequate and personalized treatment of patients.

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury

Background

To assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test.

Method

One-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline.

Results

In MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups.

Conclusion

Simultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

Anterolateral Ligament and Kaplan Fiber Injury Both Occur Frequently in Acute Anterior Cruciate Ligament-Injured Knees

BACKGROUND AND OBJECTIVES

The association of ALL and KF injuries in anterior cruciate ligament (ACL)-deficient knees remain topics of conflicting research despite improved magnetic resonance imaging (MRI). We aimed to evaluate the rate of the anterolateral ligament (ALL) and Kaplan fibers (KF) injuries in adults with acute ACL injuries using MRI.

METHODS

We retrospectively reviewed 64 patients with clinical and MRI diagnoses of acute ACL tears. Two radiologists analyzed and categorized the status of the ALL and KF in all patients as intact, partially injured, or completely injured. Interobserver agreement was assessed. Injuries to the collateral ligaments, ITB and posterior cruciate ligament (PCL) were also evaluated.

RESULTS

The mean age of the patients was 33 years. ALL injuries were observed in 46 (71%) patients, among whom 33 (71%) had partial and 13 (28%) had complete injuries. KF injuries were identified in 32 (50%) patients, with 28 (87.5%) of them having partial and 4 (12.5%) having complete injuries. Combined injuries of both ALL and KF were found in 25 (32.4%) patients (p-value of 0.266). The agreement between the examiners ranged from moderate to substantial (Kappa between 0.55 and 0.75), with the highest agreement observed in cases of KF injuries (Kappa = 0.75).

CONCLUSIONS

ALL and KF injuries were prevalent in acute ACL-injured knees with rates of injury of 71% and 50%, respectively. ALL injuries were more frequent and more frequently severe compared to KF injuries.

Reconstruction Considerations Following Complete Excision of Mucoid-Degenerated Anterior Cruciate Ligament: A Retrospective Study

INTRODUCTION

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is an unusual cause of knee pain and restricted movement, predominantly affecting the middle-aged population. Arthroscopic partial or total debridement of the mucoid ACL is the surgical treatment of choice. However, little is discussed in the literature regarding subsequent knee instability and functional outcomes following complete ACL excision.

METHODS

A retrospective study was conducted on patients who underwent arthroscopic total ACL excision for mucoid ACL. Pre- and post-operatively, the Tegner-Lysholm score, the International Knee Documentation Committee (IKDC) Subjective Knee Form, and subjective functional instability were used to grade the clinical outcomes.

RESULTS

Ten out of the 13 patients who underwent complete ACL excision were available for evaluation. All patients presented with knee pain on deep flexion or extension with a painfully limited range of motion. Post-operatively, all patients were relieved of their original pain and dysfunction. The mean post-operative IKDC and Tegner-Lysholm scores were 74.96 and 83.6, respectively. All patients had a Lachman test positive, while only two had a grade 1 pivot shift test positive. Two patients had occasional functional instability only after strenuous exercises. None of the patients underwent subsequent ACL reconstruction.

CONCLUSION

All patients reported improved functional outcomes. Only two out of 10 reported occasional instability during strenuous activity. Therefore, complete debridement of mucoid ACL in sedentary patients is safe and efficacious. However, active young patients may experience instability and require ACL reconstruction if it hinders their daily activities.

Lateral meniscal injury without medial meniscal injury indicates the existence of the Segond fracture in ACL-deficient knees

Background/Objective

The purpose of this study was to find factors indicating the occurrence of the Segond fracture, a specific type of anterolateral ligament injury.

Methods

From January 2015 to December 2017, we retrospectively reviewed the medical records of patients diagnosed with acute anterior cruciate ligament (ACL) injury who underwent reconstruction within 90 days of injury. Diagnosis of the Segond fracture was determined either by magnetic resonance imaging or plain radiographs. Factors examined were: age at surgery, sex, body mass index (kg/m2), status of menisci, and activities led to ACL injury. After univariate screening, multivariate logistic regression analyses were performed. Patients were divided into four groups based on the presence of lateral meniscal (LM) and/or medial meniscal (MM) injuries and compared with respect to the occurrence of Segond fractures.

Results

A total of 375 patients were included (163 males, 212 females), with mean age 25.8 years old. Among them, 22 of 375 (5.9 %) had a Segond fracture. We identified injured lateral menisci (adjusted odds ratio (aOR), 3.029; 95 % Confidence Interval (CI), 1.206-7.609; P = 0.018), intact medial menisci (aOR, 0.229; 95 % CI, 0.065-0.810; P = 0.022), and higher body mass index (aOR, 1.102; 95 % CI, 1.008-1.205; P = 0.034) as factors indicative of the occurrence of Segond fracture. LM injury without MM injury suggested the existence of a Segond fracture.

Conclusion

LM injury without a MM injury indicated the occurrence of a Segond fracture. Higher body mass index also increased the risk for Segond fracture occurrence.

Standardized multi-planar reformation improves the reliability of the assessment of the anterolateral ligament in ACL-deficient knees

PURPOSE

The anterolateral ligament (ALL) is an important structure for controlling anterolateral rotatory stability of the knee. Its assessment, however, is difficult using standardized MRI images. The goal of this study was to assess the reliability of judging the integrity of the ALL on multi-planar reformatted (MPR) MRI images and on standard coronal reformatted (SCR) MRI images in knees with an anterior cruciate ligament (ACL) rupture.

METHODS

Forty-eight patients (14 females, 34 males, 30 ± 6 years (mean age ± standard deviation)) with acute ACL ruptures (< 2 weeks) and no additional knee injuries (except segond fractures) were included. Images were assessed by two independent raters twice with at least a 2-week interval in between. The assessment was first performed on SCR images and thereafter on MPR images. Images were judged for assessability of the ALL and then the integrity of the ALL was rated.

RESULTS

Depending on rater and read, the ALL was judged as "torn" in between 5 (10.4%) and 11 (22.9%) patients out of 48 patients on SCR images. On MRP images, the ALL was judged as "torn" in between 5 (10.4%) and 6 (12.5%) patients out of 48 patients, depending on rater and read. Inter- and intra-rater reliability for the assessment of the ALL using MPR images was "substantial" to "almost perfect". Inter- and intra-rater reliability for the assessment using SCR was "fair" to "substantial".

CONCLUSION

MPR images should be used when assessing the integrity of the ALL. Assessment quality is independent of patient positioning during MRI acquisition and the ALL can be displayed in full length on one image.

LEVEL OF EVIDENCE

Level III.

Surgical Treatment for Avulsion Fractures of the Anterolateral Ligament Associated with Periarticular Fractures of the Knee

The existence and anatomy of the anterolateral ligament (ALL) of the knee are a somewhat controversial topic in orthopaedic surgery. The fixation of the avulsion fracture of the ALL (Segond fracture), associated with periarticular knee fractures, is rarely given much consideration while the major fracture fragments are reconstructed. This study aims to confirm the existence of ALL and evaluate the clinical outcomes of surgical management for avulsion fractures, involving its insertion, when associated with periarticular knee fractures. Twenty-three patients (16 males and 7 females) with avulsion fractures of the ALL associated with periarticular knee fractures were fixed with a spider plate, cannulated screw, or suture anchor. Eight patients were diagnosed with distal femoral fracture, 10 with tibial plateau fracture, and 5 with tibial eminence avulsion fracture. All patients underwent X-rays at follow-up. Clinical and functional outcomes were assessed with the pivot-shift test, objective and subjective International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale. The ALL was found and identified as a distinct ligamentous structure in all patients. Prior to Segond repair, patients had significantly more instability, as determined by pivot-shift test, than seen postoperatively (p < 0.0001). At final follow-up, the mean subjective IKDC score was 83.2 ± 10.3. Fourteen patients were graded A, 6 were graded B, and 3 was graded C on the IKDC objective score. The mean Lysholm score was 85.4 ± 12.2. The mean Tegner score was 7.5 ± 1.2. This study confirmed that the ALL is a distinct structure in the anterolateral portion of the knee. The fixation of the avulsion fracture of the ALL associated with periarticular knee fractures can be an effective procedure without specific complications. Long-term and comparative follow-up studies are necessary to confirm the effects.

Comparison of Anterior Cruciate Ligament Reconstruction With Versus Without Anterolateral Augmentation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

It is clear that the anterolateral ligament has an important role in rotational knee stability. However, whether patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) can benefit from anterolateral augmentation (ALA) is still controversial.

Purpose

To compare the effects of isolated ACLR versus ACLR combined with ALA (ACLR+ALA) on clinical outcomes and knee stability.

Study Design

Systematic review; Level of evidence, 1.

Methods

The methodology followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search of the PubMed, Embase, and Cochrane Library Central Register of Controlled Trials databases was undertaken to identify all randomized controlled trials (RCTs) comparing isolated ACLR with ACLR+ALA for the treatment of ACL injuries in the last 15 years. The Cochrane Collaboration risk-of-bias tool and the revised Jadad scale were utilized by 2 independent reviewers to determine the quality of RCTs. Relevant data were extracted and compared between procedures, and heterogeneity across the RCTs was assessed using the I ² statistic.

Results

The initial search yielded 849 articles. A total of 14 studies (1850 patients; 941 ACLR and 909 ACLR+ALA) satisfied the eligibility criteria for the meta-analysis. There were no significant differences between the procedures in terms of patient-reported outcomes (International Knee Documentation Committee score, Tegner score, Knee injury and Osteoarthritis Outcome Score) or return-to-sport rates. However, patients who underwent ACLR+ALA had better knee stability based on the pivot-shift test (risk ratio [RR], 1.06 [95% CI, 1.02 to 1.10]; P = .0008), Lachman test (RR, 1.03 [95% CI, 1.00 to 1.07]; P = .04), and side-to-side difference in anterior laxity (standardized mean difference, -0.55 [95% CI, -0.98 to -0.12]; P = .01) as well as a lower incidence of graft failure (RR, 0.30 [95% CI, 0.19 to 0.45]; P < .01) compared with patients who underwent isolated ACLR.

Conclusion

ALA can be considered as a reinforcement of ACLR to improve anteroposterior and anterolateral rotational stability of the knee and reduce the risk of failure. The patient-reported outcomes of isolated ACLR were similar to those of ACLR+ALA, and both procedures provided improved knee function.

The anterior cruciate ligament injury severity scale (ACLISS) is an effective tool to document and categorize the magnitude of associated tissue damage in knees after primary ACL injury and reconstruction

PURPOSE

To develop a tool allowing to classify the magnitude of structural tissue damage occurring in ACL injured knees. The proposed ACL Injury Severity Scale (ACLISS) would provide an easy description and categorization of the wide spectrum of injuries in patients undergoing primary ACL reconstruction, reaching from isolated ACL tears to ACL injuries with a complex association of combined structural damage.

METHODS

A stepwise approach was used to develop the ACLISS. The eligibility of each item was based on a literature search and a consensus between the authors after considering the diagnostic modalities and clinical importance of associated injuries to the menisci, subchondral bone, articular cartilage or collateral ligaments. Then, a retrospective analysis of associated injuries was performed in 100 patients who underwent a primary ACL reconstruction (ACLR) by a single surgeon. This was based on acute preoperative MRI (within 8 weeks after injury) as well as intraoperative arthroscopic findings. Depending on their prevalence, the number of selected items was reduced. Finally, an analysis of the overall scale distribution was performed to classify the patients according to different injury profiles.

RESULTS

A final scoring system of 12 points was developed (12 = highest severity). Six points were attributed to the medial and lateral tibiofemoral compartment respectively. The amount of associated injuries increased with ACLISS grading. The median scale value was 4.5 (lower quartile 3.0; higher quartile 7.0). Based on these quartiles, a score < 4 was considered to be an injury of mild severity (grade I), a score between ≥ 4 and ≤ 7 was defined as moderately severe (grade II) and a score > 7 displayed the most severe cases of ACL injuries (grade III). The knees were graded ACLISS I in 35%, ACLISS II in 49% and ACLISS III in 16% of patients. Overall, damage to the lateral tibiofemoral compartment was predominant (p < 0.01), but a proportional increase of tissue damage could be observed in the medial tibiofemoral compartment with the severity of ACLISS grading (p < 0.01).

CONCLUSIONS

The ACLISS allowed to easily and rapidly identify different injury severity profiles in patients who underwent primary ACLR. Injury severity was associated with an increased involvement of the medial tibiofemoral compartment. The ACLISS is convenient to use in daily clinical practice and represents a feasible grading and documentation tool for a reproducible comparison of clinical data in ACL injured patients.

LEVEL OF EVIDENCE

Level III.

The anterolateral capsule is infrequently damaged as evaluated arthroscopically in patients undergoing anatomic ACL reconstruction

OBJECTIVES

Concomitant anterolateral complex (ALC) injury may contribute to persistent rotatory knee instability following anterior cruciate ligament (ACL) reconstruction. There is no consensus on how to best identify concomitant ALC injury preoperatively, nor how well ALC injury identified on imaging modalities correlates with clinical examination of knee instability. The purpose of this retrospective study was to determine the incidence of concomitant ALC injury in ACL-injured knees, as determined by arthroscopy to preoperative radiography, ultrasound, and MRI.

METHODS

A total of 117 patients with a unilateral primary ACL injury who underwent individualized anatomic ACLR between June 2016 and May 2019 were enrolled. Preoperative imaging modalities, including X-ray, ultrasound, and MRI, were evaluated for concomitant ALC injury. Clinical examination under anesthesia, including the anterior drawer, Lachman, and pivot shift tests were performed. Anterolateral capsule injury, as defined by hemorrhage and/or capsular tearing on diagnostic arthroscopy, was also determined. Correlative analyses of ALC injury incidence and severity were performed across imaging modalities and against clinical examination grades.

RESULTS

ALC injury incidence across imaging modalities was as follows: X-ray (3%), arthroscopy (19%), MRI (53%), and US (63%). The ALC injury rate on arthroscopy was significantly less than MRI (p < 0.001) or ultrasound (p < 0.001). ALC injury incidence and severity were significantly correlated between MRI and US grading scales (p = 0.02), but no correlations among other imaging modalities were found. Similarly, no imaging modality meaningfully correlated with physical examination maneuvers.

CONCLUSION

The incidence of ALC injury varies across imaging modalities, with lower injury rates found on arthroscopy (19%) compared to MRI (53%) and US (63%). Increasing ALC injury severity grades on imaging does not predict increasing anterolateral knee laxity on clinical examination.

LEVEL OF EVIDENCE

V, retrospective case series.

Influence of Injury to the Kaplan Fibers of the Iliotibial Band on Anterolateral Rotatory Knee Laxity in Anterior Cruciate Ligament Injury: A Retrospective Cohort Study

BACKGROUND

Biomechanical cadaveric studies have shown that Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotatory knee laxity in anterior cruciate ligament (ACL) injury. However, in the clinical setting, the contribution of injury to KFs on anterolateral rotatory laxity remains unclear.

PURPOSE

To use magnetic resonance imaging (MRI) scans to detect concomitant KF injury in ACL-injured knees and to then examine the effect of KF injury on anterolateral rotatory laxity as measured by the pivot-shift test in a clinical setting.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The study enrolled 91 patients with primary ACL tears (mean age 25 ± 11 years; 46 male and 45 female) whose MRI was conducted within 90 days after injury. KF injury was assessed by MRI according to previously reported criteria, and the patients were allocated to a KF injury group and a no-KF injury group. At the time of ACL reconstruction, the pivot-shift test was performed with the patient under anesthesia and quantitatively evaluated by tibial acceleration using an electromagnetic measurement system. Manual grading of the pivot-shift test was assessed according to guidelines of the International Knee Documentation Committee. The data were statistically compared between the 2 groups using Mann-Whitney U test and Fisher exact test (P < .05).

RESULTS

KFs were identified in 85 patients (93.4%), and KF injury was detected in 20 of the 85 patients (23.5%). No significant differences were observed between the KF injury group (n = 20) and the no-KF injury group (n = 65) in demographic characteristics, the period from injury to MRI (8.0 ± 14.0 days vs 8.9 ± 12.1 days, respectively), the rate of meniscal injury (50.0% vs 53.8%), or the rate of anterolateral ligament injury (45.0% vs 44.6%). Regarding the pivot-shift test, no significant differences were observed in tibial acceleration (1.2 m/s² [interquartile range, 0.5-2.1 m/s²] vs 1.0 m/s² [interquartile range, 0.6-1.7 m/s²], respectively) or manual grading between the 2 groups.

CONCLUSION

Concomitant KF injury did not significantly affect the pivot-shift phenomenon in acute ACL-injured knees. The findings suggest that the contribution of KF injury to anterolateral rotatory knee laxity may be limited in the clinical setting.

Tibial internal rotation in combined anterior cruciate ligament and high-grade anterolateral ligament injury and its influence on ACL length

Background

Assessment of combined anterolateral ligament (ALL) and anterior cruciate ligament (ACL) injury remains challenging but of high importance as the ALL is a contributing stabilizer of tibial internal rotation. The effect of preoperative static tibial internal rotation on ACL -length remains unknown. The aim of the study was analyze the effect of tibial internal rotation on ACL length in single-bundle ACL reconstructions and to quantify tibial internal rotation in combined ACL and ALL injuries.

Methods

The effect of tibial internal rotation on ACL length was computed in a three-dimensional (3D) model of 10 healthy knees with 5° increments of tibial internal rotation from 0 to 30° resulting in 70 simulations. For each step ACL length was measured. ALL injury severity was graded by a blinded musculoskeletal radiologist in a retrospective analysis of 61 patients who underwent single-bundle ACL reconstruction. Preoperative tibial internal rotation was measured in magnetic resonance imaging (MRI) and its diagnostic performance was analyzed.

Results

ACL length linearly increased 0.7 ± 0.1 mm (2.1 ± 0.5% of initial length) per 5° of tibial internal rotation from 0 to 30° in each patient.

Seventeen patients (27.9%) had an intact ALL (grade 0), 10 (16.4%) a grade 1, 21 (34.4%) a grade 2 and 13 (21.3%) a grade 3 injury of the ALL. Patients with a combined ACL and ALL injury grade 3 had a median static tibial internal rotation of 8.8° (interquartile range (IQR): 8.3) compared to 5.6° (IQR: 6.6) in patients with an ALL injury (grade 0–2) (p = 0.03). A cut-off > 13.3° of tibial internal rotation predicted a high-grade ALL injury with a specificity of 92%, a sensitivity of 30%; area under the curve (AUC) 0.70 (95% CI: 0.54–0.85) (p = 0.03) and an accuracy of 79%.

Conclusion

ACL length linearly increases with tibial internal rotation from 0 to 30°. A combined ACL and high-grade ALL injury was associated with greater preoperative tibial internal rotation. This potentially contributes to unintentional graft laxity in ACL reconstructed patients, in particular with concomitant high-grade ALL tears.

Study design

Cohort study; Level of evidence, 3.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05218-8.

There are differences in knee stability based on lateral extra-articular augmentation technique alongside anterior cruciate ligament reconstruction

PURPOSE

The purpose of the current study is to systematically review and network meta-analyze the current evidence in the literature to ascertain if there is a superior lateral extra-articular augmentation technique in conjunction with anterior cruciate ligament (ACL) reconstruction (ACL.R) with respect to knee stability, re-rupture rates and functional outcomes.

METHODS

The literature search was performed based on the PRISMA guidelines. Cohort studies comparing ACL.R to ACL.R + lateral extra-articular augmentation were included. Lateral extra-articular techniques included were anterolateral ligament reconstruction (ALL.R), Cocker-Arnold, Lemaire, Losee, Maraccaci, and McIntosh. Clinical outcomes were compared between ACL.R alone and the different lateral extra-articular augmentation techniques using a frequentist approach to network meta-analysis, with statistical analysis performed using R. The treatment options were ranked using the P-Score.

RESULTS

Twenty-eight studies with a total of 2990 patients were included. ACL.R + Cocker-Arnold technique had the highest P-Score for ACL re-ruptures and residual pivot-shift. ACL.R + Cocker-Arnold, Lemaire, and ALL.R all significantly reduced the rate of ACL re-rupture, and residual pivot-shift, compared to ACL.R alone. There was no significant difference between any of the lateral extra-articular augmentation techniques and ACL.R alone. ALL.R had the highest P-Score for return to play, and return to play at pre-injury level.

CONCLUSION

This study established that ACL.R + Cocker-Arnold, Lemaire and ALL.R resulted in significantly lower ipsilateral ACL re-ruptures, as well as reduced pivot-shift, compared to ACL.R alone. Whereas, the other lateral extra-articular augmentation techniques did not reduce pivot-shift and re-rupture. Additionally, functional outcomes and return to play were comparable between those who underwent ACL.R and lateral extra-articular augmentation and ACL.R alone.

LEVEL OF EVIDENCE

III.

Multiplanar reformation improves identification of the anterolateral ligament with MRI of the knee

The anterolateral ligament (ALL) is subject of the current debate concerning rotational stability in case of anterior cruciate ligament (ACL) injuries. Today, reliable anatomical and biomechanical evidence for its existence and course is available. Some radiologic studies claim to be able to identify the ALL on standard coronal plane MRI sections. In the experience of the authors, however, ALL identification on standard MRI sequences frequently fails and is prone to errors. The reason for this mainly lies in the fact, that the entire ALL often cannot be identified on a single MRI image. This study aimed to establish an MRI evaluation protocol improving the visualization of the ALL, using multiplanar reformation (MPR) with the goal to be able to evaluate the ALL on one MRI image. A total of 47 knee MRIs performed due to atraumatic knee pain between 2018 and 2019 without any pathology were analyzed. Identification of the ALL was performed twice by an orthopedic surgeon and a radiologist on standard coronal plane and after MPR. For the latter axial and coronal alignment was obtained with the femoral condyles as a reference. Then the coronal plane was adjusted to the course of the ALL with the lateral epicondyle as proximal reference. Visualization of the ALL was rated as “complete” (continuous ligamentous structure with a tibial and femoral insertion visible on one coronal image), “partial” (only parts of the ALL like the tibial insertion were visible) and “not visible”. The distances of its tibial insertion to the bony joint line, Gerdy’s tubercle and the tip of the fibular head were measured. On standard coronal images the ALL was fully visible in 17/47, partially visible in 27/47, and not visible in 3/47 cases. With MPR the ALL was fully visible in 44/47 and not visible in 3/47 cases. The median distance of its tibial insertion to the bony joint line, Gerdy’s tubercle and the tip of the fibular head were 9, 21 and 25 mm, respectively. The inter- (ICC: 0.612; 0.645; 0.757) and intraobserver (ICC: 0.632; 0.823; 0.857) reliability was good to excellent. Complete visualization of the ALL on a single MRI image is critical for its identification and evaluation. Applying multiplanar reformation achieved reliable full-length visualization of the ALL in 94% of cases. The described MPR technique can be applied easily and fast in clinical routine. It is a reliable tool to improve the assessment of the ALL.

Editorial Commentary: Lateral Extra-Articular Tenodesis Results in Better Stability After Anterior Cruciate Ligament Reconstruction for Patients With High-Grade Pivot Shifts

Magnetic resonance imaging of the torn anterior lateral ligament (ALL) is inconsistent and subject to significant intra- and interobserver variability. Like that of an anterior cruciate ligament (ACL), an ALL tear can vary in degree (first, second, or third) and location (tibial or femoral side). These variations may impact the appropriate surgical intervention. Relevant biomechanical data indicate that the deep iliotibial band fibers are more important than the ALL in controlling pivot shift. Lateral compartment overconstraint after ALL reconstruction does not appear to be a biomechanical or clinical issue. An ALL reconstruction creates a nonisometric construct (tight in extension and lax in flexion), allowing physiologic internal tibial rotation at 90° flexion, whereas lateral extra-articular tenodesis (LET) is more isometric, limiting physiologic internal tibial rotation at 90° flexion. The indications for a combined ACL/ALL reconstruction are evolving, but a Segond fracture and ligamentous hyperlaxity of ≥5 using the modified Beighton system seem reasonable. An ACL/LET reconstruction results in better stability for patients with high-grade pivot shifts.

Antero-lateral ligament reconstruction improves knee stability alongside anterior cruciate ligament reconstruction

PURPOSE

Recent evidence has found the antero-lateral ligament (ALL) may play a role in stabilizing the knee, but its role in anterior cruciate ligament (ACL) reconstruction is controversial. The purpose of the current study is to systematically review and meta-analyze the current evidence in the literature to ascertain whether ACL reconstruction combined with ALL reconstruction affects knee stability, re-rupture rates and patient-reported outcomes compared to ACL reconstructions performed alone.

METHODS

A literature search was performed based on the PRISMA guidelines. Cohort studies comparing ACL + ALL reconstruction and ACL reconstruction alone were included.

RESULTS

Six clinical trials (LOE I: I, LOE II: 2, LOE III: 3) with 729 patients were included, with a mean follow-up time of 34.2 (24-54.9) months. There was a significant difference in favor of combined ACL + ALL reconstruction for reduced re-rupture rate (2.4% vs 7.3%, p < 0.01), residual positive pivot shift rate (33.3% vs 11.4%, p < 0.01), and reduced KT-arthrometer evaluation (1.6 vs 2.6, p < 0.01). Combined ACL + ALL reconstruction resulted in improved IKDC scores (92.5 vs 87.8, p < 0.01), Lysholm scores (95.7 vs 91.2, p < 0.01) and Tegner scores (6.7 vs 5.7, p < 0.01). There was no significant difference in rate of return to play at the same level (54.3% vs 46.0%, n.s.).

CONCLUSION

The current evidence suggests alongside soft tissue graft ACL reconstruction that concomitant ALL reconstruction improves clinical outcomes, with improved knee stability and lower re-rupture rates.

LEVEL OF EVIDENCE

III.

A Retrospective Comparison of Single-Bundle Anterior Cruciate Ligament Reconstruction With Lateral Extra-Articular Tenodesis With Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To compare postoperative objective knee stability and clinical outcomes between double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) and single-bundle (SB) ACLR combined with lateral extra-articular tenodesis (LET).

METHODS

ACL-injured patients with grade 3 pivot-shift who underwent either DB ACLR (DB ACLR group) or SB ACLR with LET (SB ACLR+LET group) were enrolled. All patients who met inclusion and exclusion criteria were retrospectively evaluated for knee laxity (the anterior translation and pivot-shift grade), clinical outcomes using the International Knee Documentation Committee (IKDC) examination form, Kellgren-Lawrence grade, graft maturation score on second-look arthroscopy, and revision rates at the last follow-up.

RESULTS

From an initial cohort of 171 consecutive patients over a 3-year period, 95 (56%) met inclusion and exclusion criteria. The SB ACLR+LET group (n = 47) showed significantly better results in pivot-shift grade at the last follow-up as compared with the DB ACLR group (n = 48) (P = .021). In the SB ACLR+LET group, 93.6% (44/47) were grade 0, whereas 72.9% (35/48) in the DB ACLR group were grade 0. The SB ACLR+LET group (grade A: 42, grade B: 4 and grade C: 1) showed significantly superior results in IKDC objective grade compared with the DB ACLR group (grade A: 32; grade B: 8; and grade C: 8) (P = .017). However, no statistically significant difference could be shown in anterior translation, subjective functional IKDC score, or revision rate between the 2 groups. The mean follow-up duration was 49.7 ± 5.7 months.

CONCLUSIONS

SB ACLR + LET demonstrated fewer pivot-shifts (P = .021) and superior IKDC objective grades (P = .017) than a DB ACLR at a mean follow-up of almost 50 months.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Degree of Anterolateral Ligament Injury Impacts Outcomes After Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To evaluate the effect of anterolateral ligament (ALL) injury identified on preoperative magnetic resonance imaging (MRI) on postoperative outcomes after double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

For this retrospective study, the inclusion criteria were patients who were at least 3 years out of DB ACLR. Exclusion criteria included a delay in MRI over 4 weeks, delay in surgery over 6 months, single-bundle ACLR, and revision surgery. Enrolled patients were divided into 2 groups according to the ALL injury grade in preoperative MRI by a musculoskeletal radiologist who was blinded to the perioperative findings (the high-grade group with complete or nearly complete tear: n = 53 and the low-grade group with intact ALL or partial tear: n = 33). Knee laxity, clinical outcomes using the International Knee Documentation Committee (IKDC) examination form, and revision rates were compared at the last follow-up (8.1 ± 2.2 years). An independent t test was applied to compare continuous variables, and χ² or Fisher exact test was used to compare the nominal variables.

RESULTS

The anterior translation was 3.2 ± 1.9 mm in the high-grade group and 1.6 ± 1.0 mm in the low-grade group (P < .001). The high-grade group showed 18 cases with a pivot-shift grade of 2 or 3 (40.0%); however, the low-grade group showed only 1 case with a pivot-shift grade 2 or 3 (3.0%) (P = .002). The high-grade group also showed inferior outcomes in the IKDC objective grade (grade A: 49.0%; grade B: 17.0%; grade C: 30.2%; grade D: 3.8% vs grade A: 90.9%; grade B: 6.1%; grade C: 3.0%; grade D: 0%, P = .001) and IKDC subjective score (87.5 ± 9.9 vs 93.9 ± 5.3, P < .001). In addition, the high-grade group showed a greater revision rate (11.3% vs 0%, P = .045).

CONCLUSIONS

DB ACLR for patients with high-grade ALL injury resulted in increased knee laxity, worse clinical outcomes, and higher revision rate compared to patients with low-grade ALL injury.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Painful Palpation of the Tibial Insertion of the Anterolateral Ligament Is Concordant With Acute Anterolateral Ligament Injury

Background

The anterolateral ligament (ALL) has been shown to contribute to the rotational stability of the knee. However, no clinical sign specific to ALL injury has been described.

Purpose/Hypothesis

The primary aim of this study was to determine the concordance between pain elicited upon ALL palpation and ALL injury diagnosed by ultrasonography (US). The secondary aim was to look for a relationship between ALL injury and high-grade pivot shift. We hypothesized that an ALL lesion can be diagnosed clinically in an acute knee injury by palpating its tibial insertion.

Study Design

Cohort study (diagnosis); Level of evidence, 2.

Methods

A total of 130 patients (89 men, 41 women; mean age, 27.2 ± 8.3 years) with an acute, isolated anterior cruciate ligament injury who were scheduled for ligament reconstruction were enrolled in this study. ALL palpation was carried out a mean 8.8 ± 3.2 days after injury. Preoperatively, ALL integrity was evaluated with US, and the pivot shift was determined under general anesthesia. The agreement between pain upon ALL palpation and ALL injury detected on US was determined by calculating the intraclass correlation coefficient (ICC), along with 95% CIs.

Results

Distal palpation of the ALL tibial insertion elicited pain in 67 (51.5%) patients, and upon US the ALL was found to be damaged in 64 (49.2%) patients. The agreement between pain over the ALL tibial insertion and the ALL being damaged on US was excellent (ICC, 0.801; 95% CI, 0.730-0.855). Moreover, the clinical test had excellent sensitivity (92%; 95% CI, 88%-97%) and specificity (88%; 95% CI, 82%-93%). The agreement between pain at the ALL distal insertion and the pivot shift was good (ICC, 0.654; 95% CI, 0.543-0.742), and ALL palpation had excellent diagnostic accuracy for identifying rotational instability (sensitivity, 88% [95% CI, 82%-93%]; specificity, 97% [95% CI, 94%-100%]).

Conclusion

Palpation of the ALL tibial insertion highly correlates with ultrasonographic evidence of an ALL injury in the context of an acute knee injury. This simple test should become part of our standard examination when evaluating patients with acute knee injuries.

[Research progress in anterolateral ligament of knee]

Objective

To review research progress in the anterolateral ligament (ALL) of knee, and provide a clinical reference for diagnosis and treatment of ALL injury.

Methods

The literature on the diagnosis and treatment of ALL injury was widely reviewed. The incidence, anatomy, biomechanics, injury mechanism, and treatment status of ALL were summarized.

Results

The ALL contributes to the effect of controlling the internal rotation and anterior translation of the tibia, which affects the axial migration of the knee. ALL injury can be diagnosed according to the signs and MRI examination. Currently, no consensus exists for the surgical indications of ALL injury, but most surgeons tend to perform ALL reconstruction in patients requiring anterior cruciate ligament (ACL) reconstruction or revision surgery with higher pivot-shift tests. At present, various techniques have been used for ALL reconstruction, and there is no optimal technique. In addition, the long-term effectiveness of ALL reconstruction is unclear due to the lack of high-quality studies and long-term postoperative follow-up.

Conclusion

The ALL contributes to maintaining knee stability, and the ALL reconstruction technique and its effectiveness still need further research.

Evaluation of Anterolateral Ligament Healing After Anatomic Anterior Cruciate Ligament Reconstruction

BACKGROUND

Few studies have reported the healing process of anterolateral ligament (ALL) injuries.

PURPOSE/HYPOTHESIS

This study investigated the healing status of ALL injuries after primary anterior cruciate ligament (ACL) reconstruction (ACLR). Additionally, we investigated the association between the healing status of ALL injuries and associated lesions such as osseous lesions and meniscal tears occurring at the time of an ACL rupture. We hypothesized that acute ALL injuries show a high rate (more than two-thirds) of healing at the 1-year follow-up after ACLR and that concomitant lesions observed at the time of an ACL rupture affect the healing status of the ALL.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

We retrospectively investigated patients with ALL injuries who underwent primary ACLR between March 2015 and February 2017. Using magnetic resonance imaging (MRI), we evaluated the features of ALL injuries and concomitant lesions, and MRI was performed at the 1-year follow-up to assess the healing status of the ALL. We investigated the association between the healing status of the ALL and concomitant lesions observed at the time of an ACL rupture. A subjective assessment was performed using the Lysholm score, International Knee Documentation Committee subjective score, and Tegner activity scale. Objective tests included an isokinetic strength assessment and functional performance testing.

RESULTS

With respect to the severity of ALL injuries, of 54 patients, a complete rupture occurred in 16 (29.6%) of the 54 patients and a partial rupture in 38 (70%). A significant association was observed between the severity of ALL injuries and bone contusions (lateral tibial plateau and medial tibial plateau [MTP]) and meniscus ramp lesions (Fisher exact test: P = .023, .012, and .023, respectively). Good and partial healing of the ALL occurred in 16 (29.6%) and 23 (42.6%) of 54 patients, respectively. Scar formation occurred in 12 (22.2%), and nonvisualization of the ALL was observed in 3 (5.6%) of 54 patients. Poor healing of the ALL was associated with preoperative MTP bone contusions and a high-grade pivot shift. Multivariate analysis showed that an MTP bone contusion was an independent risk factor associated with poor healing of the ALL. Among the functional tests performed, significant differences were observed between the good and poor healing groups with respect to the carioca test (P = .039). The good healing group (n = 16) showed a negative pivot shift at the last follow-up, whereas 5 (13.2%) of the patients from the poor healing group (n = 38) showed a positive pivot shift, including 2 (5.3%) with a high-grade pivot shift.

CONCLUSION

Approximately 70% of acute ALL injuries showed poor healing at the 1-year follow-up. Poor healing of ALL injuries was significantly associated with preoperative MTP bone contusions and a high-grade pivot shift. Therefore, a careful assessment of posteromedial bone contusions at the time of an ACL rupture is warranted, particularly in patients with a high-grade pivot shift.

Knee laxity in anterolateral complex injuries versus lateral meniscus posterior horn injuries in anterior cruciate ligament deficient knees: A cadaveric study

BACKGROUND

In the anterior cruciate ligament (ACL) injured knee, additional injury of the anterolateral ligament (ALL) and capsule may increase the pathologic laxity. The purpose of this study was to compare the effects of the anterolateral complex (ALC) injury in ACL injured knee with the effects of lateral meniscus posterior horn (LMPH) meniscectomy.

METHODS

Ten fresh-frozen cadaveric knees were used. After testing the (1) intact knees and (2) ACL sectioned knees (ACL-), two groups were established: an (3) ALC sectioning group (n = 5), which underwent additional ALC sectioning (ACL-/ALC-) after ACL sectioning, and a separate (3) LMPH meniscectomy group (n = 5) that underwent LMPH meniscectomy (ACL-/LMPH-) after ACL sectioning. Knee laxity was measured in terms of internal-external rotation, anterior-posterior translation, and varus-valgus angulation for each condition at knee flexion angles of 0°, 30°, 60° and 90°.

RESULTS

After additional sectioning of the ALC (ACL-/ALC-), the mean internal rotation at 0, 30, 60 and 90° of knee flexion was 11.9 ± 1.3°, 18.1 ± 1.6°, 18.3 ± 1.8°, and 17.8 ± 2.4°, respectively, showing significant internal rotation laxity when compared to the intact knee (P = .031, .020, .001 and .033). Anterior translation also significantly increased compared to the ACL- knee at 30° (12.7 ± 1.4 to 16.8 ± 1.7 mm: P = .039). In contrast, additional meniscectomy of the LMPH (ACL-/LMPH-) significantly increased valgus laxity compared to the intact knee at 30, 60 and 90° (P = .021, .018 and .024).

CONCLUSION

These findings suggest that the anterolateral complex, which include the ALL and anterolateral capsule, may play an important role in stabilizing the knee against internal rotation and anterior translation.

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.

Editorial Commentary: Magnetic Resonance Imaging of the Knee Anterolateral Ligament: Does It Really Matter?

Great interest remains in the structures of the knee anterolateral complex and how they work synergistically with the anterior cruciate ligament to control anterolateral rotatory laxity. Many studies have now used magnetic resonance imaging to assess the degree of damage to the anterolateral ligament. The systematic review described in this commentary rigorously highlights the many deficiencies that exist within our current understanding of the imaging analysis of these structures. Marked variability in the definition of anterolateral ligament injury, significant methodological differences, and the lack of a gold standard reference make it very challenging to translate the findings of these imaging studies into clinical practice. More information is required to fully understand the injury pattern, and then clinical studies are needed to guide treatment. Hopefully we will then have the ability to better treat our patients with these challenging complex laxity patterns that exist over and above an isolated anterior cruciate ligament injury.