A cadaveric study of the anterolateral ligament: re-introducing the lateral capsular ligament

Patients With Segond Fracture Demonstrate Similar Rates of Return to Sport and Psychological Readiness After Anterior Cruciate Ligament Reconstruction: A Matched Cohort Study at Minimum 2-Year Follow-Up

PURPOSE

To compare clinical outcomes, rate of return to sports, and psychological readiness among patients undergoing anterior cruciate ligament reconstruction (ACLR) with and without concomitant Segond fracture.

METHODS

We retrospectively identified patients who underwent primary ACLR from January 2012 to December 2020 with minimum 2-year follow-up. Exclusion criteria were additional ligamentous injury, age <16 years, or a concomitant lateral augmentation procedure. Preoperative knee radiographs were reviewed to identify Segond fractures. Identified patients were matched 1:2 to controls by age/sex/body mass index/graft type. Charts were reviewed for pre- and postoperative knee stability. Surveys administered included preinjury sport participation and return status, Lysholm score, Tegner activity scale, and ACL-Return to Sport Index (ACL-RSI), a metric of psychological sport readiness. Multivariable logistic regression was conducted to identify predictors of return to sport.

RESULTS

There were 120 patients who were included in the final analysis (40 Segond, 80 controls) at a mean follow-up of 5.7 ± 2.4 years. A total of 52.5% of patients received bone-patellar tendon-bone autograft. The overall rate of return to sport was 79.5% in the Segond group compared with an 83.8% rate of return in the control group (P = .569). In total, 48.7% of the Segond group and 56.8% of the control group returned to their preinjury level of sport (P = .415). Lysholm (89.6 ± 10.3 vs 85.4 ± 16.7, P = .296), Tegner (5.7 ± 1.8 vs 6.1 ± 2.2, P = .723), and ACL-RSI (62.2 ± 25.4 vs 56.6 ± 25.4, P = .578) scores were similar between Segond and control groups. There was a single graft failure in the Segond group 5 years' postoperatively. Increasing ACL-RSI score was significantly predictive of return to sport (P < .001).

CONCLUSIONS

Patients who had an ACL tear and a concomitant Segond fracture who underwent isolated ACLR without lateral augmentation procedures had similar clinical outcomes and rates of return sport compared with a matched isolated ACLR control group at minimum 2-year follow-up. There was no significant difference in psychological readiness between groups as measured by the ACL-RSI.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Anterolateral Ligament of the Knee Is a Nonisometric Thin Ligament With High Prevalence and Almost Constant Attachment to the Lateral Meniscus: A Systematic Review With Meta-analysis

PURPOSE

To provide comprehensive information about the anterolateral ligament (ALL) prevalence, morphometry, isometry, insertions, histology, and its relationship with the lateral meniscus (LM).

METHODS

The study was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Eligible cadaveric studies investigating the frequency of the ALL presence, and anatomical features were identified through an online search of the PubMed, Scopus, and Cochrane Central databases from inception to June 2022. Statistical analysis was conducted with the open-source R programming language using the "meta" package. The Higgins I2 statistic was used for quantifying heterogeneity.

RESULTS

Thirty-three studies (1,478 cadaveric knees) were included. The ALL had a 79% prevalence. It was attached to the LM periphery in 97% of studies. Most studies reported a femoral insertion of the ALL, just proximal and posterior to the lateral epicondyle. Tibial attachment is constant at the midpoint between Gerdy's tubercle and fibular head. The mean ALL thickness at the joint line was 1.6 [1.2; 2.0] mm. The ALL length was found to significantly change across the knee flexion (P < .01). It was increased from 0° to 60° and decreased after 60° flexion. Seven histological studies demonstrated a typical ligamentous microstructure.

CONCLUSION

The ALL is a thin ligament, distinct to the knee capsule, which may be found in 79% of the knees having an almost constant attachment to the LM. The ALL is not isometric. It becomes tense during internal rotation and between 30° and 60° knee flexion. Pooled results should be interpreted with caution due to the high heterogeneity among the included studies.

CLINICAL RELEVANCE

This study sheds light on controversial issues and provides comprehensive and accurate information about the essential anatomical knowledge on ALL, which may contribute to optimizing ALL reconstruction surgical techniques and biomechanical settings.

Anterolateral augmentation procedures during anterior cruciate ligament reconstructions in skeletally immature patients: Scoping review of surgical techniques and outcomes

Purpose

Graft failure rates after anterior cruciate ligament reconstruction (ACLR) in children and adolescents are higher compared to adults. Anterolateral augmentation procedures have recently generated increased focus regarding their ability to reduce graft failure rates. Concerns in skeletally immatures are potential growth disturbances and overconstraint after anterolateral augmentation. The aim of this scoping review is to provide an overview of all current anterolateral augmentation procedures in skeletally immature patients and to discuss surgical techniques, clinical and biomechanical outcomes.

Methods

This scoping review was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement extension for scoping reviews. On 22 December 2022, an information specialist performed a systematic literature search in Cochrane, PubMed (Medline) and EMBASE databases. Inclusion criteria were anterolateral augmentation procedures, including lateral extra-articular tenodesis (LET) and anterolateral ligament reconstruction (ALLR), in combination with ACLR in skeletally immatures.

Results

Twenty studies were included after screening 1.485 abstracts. Seventeen studies describe LET techniques, four studies ALLR techniques and one study both techniques. Biomechanical data is scarce and shows conflicting results. Two studies compared ACLR with LET to ACLR in skeletally immatures with promising results in favour of the combined procedure. There were no differences in outcomes between LET and ALLR.

Conclusions

Several LET and ALLR techniques have been described for skeletally immature patients and the first clinical data on LET and ALLR is available, which showed promising results. Further research is necessary to evaluate the risk of growth disturbances and overconstraint in skeletally immatures.

Level of Evidence

Level IV.

Combined anterior cruciate ligament revision with reconstruction of the antero-lateral ligament does not improve outcome at 2-year follow-up compared to isolated acl revision; a randomized controlled trial

PURPOSE

It is essential to obtain rotational stability of the knee after anterior cruciate ligament reconstruction (ACL-R) and it is suggested that a supplementary reconstruction of the antero-lateral ligament (ALL-R) may supports this. Theoretically, ALL-R may be particularly advantageous to support revision of failed ACL-Rs. It was hypothesized that ACL revision combined with ALL-R will result in superior outcome compared to isolated ACL revision.

METHODS

The study was designed as a randomized controlled trial. Patients eligible for first time ACL revision were randomized to either isolated ACL revision (- ALL group) or ACL revision combined with a single-stranded allograft ALL-reconstruction (+ ALL group). Patient reported outcomes and function were evaluated at two-year follow-up by KNEES-ACL, KOOS, and Tegner activity scale. Objective knee laxity was evaluated at one-year follow-up using an instrumented Rolimeter test, the pivot shift test, and a manual Lachman test.

RESULTS

A total of 103 patients were enrolled with 49 patients randomized to the + ALL group and 54 patients in the - ALL group. There were no differences at baseline between groups regarding age, gender, body mass index, preoperative patient reported outcome scores and concomitant meniscus or cartilage injury. The ACL revision was performed with an allograft in 10 patients (20%) in the + ALL group and 8 patients (15%) in the -ALL group. At follow-up there was no significant difference between the groups in patient reported outcome scores and clinical knee laxity.

CONCLUSION

Supplementary ALL-R does not improve subjective outcome of first time ACL revision at two-years and clinical knee stability at one-year follow-up compared to isolated ACL revision.

LEVEL OF EVIDENCE

Level I.

The Anterolateral Ligament of the Knee in Pediatric Patients: What Do We Know? A Scoping Review

The knowledge on the anatomy, function and biomechanics and the role of surgical procedures on the anterolateral ligament (ALL) of the knee is still controversial. Only a few papers have examined the ALL in children. The aim of this review is to analyze all the available literature about ALL in the pediatric population. Following the PRISMA criteria, the literature was systematically reviewed, examining all the articles about ALL in pediatric patients. Eight articles were involved in this study. Five cadaveric studies, two diagnostic studies, and one cross-sectional study were found. The identification of the ALL is not always possible in diagnostic studies using magnetic resonance (MRI) or in dissecting specimens. A high variability in the presence of the ligament and in its origin and insertion were found among the studies. It is more difficult to identify the ligament in younger patients than in older children, suggesting that its presence may develop at some point during the growth. Further studies are needed for a detailed knowledge of the ALL.

Technique for Surgical Dissection and Histological Investigation of the Anterolateral Ligament in the Fetal Knee

There is growing evidence into the structure and function of the anterolateral ligament (ALL) of the knee. However, debate still exists about the anatomical characteristics, biomechanical role, and even the existence of the ALL, despite numerous cadaveric, biomechanical, and clinical studies. This article describes, with video illustration, the surgical dissection of the ALL in human fetal lower limbs, including determination of detailed anatomical and histological features of the ALL during fetal development. The ALL was clearly identified in dissected fetal knees, and histologic analysis shows well-organized, dense collagenous tissue fibers with elongated fibroblasts, consistent with the properties of a ligament.

Radiographic Incidence of Knee Osteoarthritis After Isolated ACL Reconstruction Versus Combined ACL and ALL Reconstruction: A Prospective Matched Study From the SANTI Study Group

BACKGROUND

Combined anterior cruciate ligament (ACL) reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) have demonstrated reduced risk of graft rerupture as compared with isolated ACLR. However, concerns remain that the risk of osteoarthritis (OA) may be increased by the addition of ALLR.

PURPOSE/HYPOTHESIS

The aim of this study was to evaluate the incidence of OA with isolated ACLR in comparison with ACLR + ALLR at medium-term follow-up. We hypothesized that there would be no differences between the groups.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent ACLR + ALLR with hamstring tendon autograft between January 2011 and March 2012 were propensity matched to patients who underwent isolated ACLR with bone-patellar tendon-bone (BPTB) or hamstring tendon autograft in the same period. Medium-term radiographic evaluation was performed using the International Knee Documentation Committee (IKDC) radiographic OA grading scale, modified Kellgren-Lawrence grade, and the surface fit method to assess percentage of joint space narrowing. Clinical outcomes were assessed with the following measures: IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm, Tegner, and ACL Return to Sport after Injury.

RESULTS

A total of 80 patients (42 ACLR + ALLR and 38 isolated ACLR) were analyzed with a mean follow-up of 104 months. There was no significant difference between groups for joint space narrowing in the medial or lateral tibiofemoral or lateral patellofemoral (PF) compartment. However, 36.8% in the isolated ACLR group versus 11.9% in the ACLR + ALLR group had narrowing of the medial PF compartment (P = .0118). A lateral meniscal tear increased the risk of lateral tibiofemoral narrowing by nearly 5 times (odds ratio, 4.9; 95% CI, 1.547-19.367; P = .0123). The risk of medial PF narrowing was >4-fold with an isolated ACLR (odds ratio, 4.8; 95% CI, 1.44-19.05; P = .0179). Between the isolated ACLR group and the ACLR + ALLR group, the secondary meniscectomy rate was 13.2% versus 11.9% (not significantly different). There was no difference between groups in KOOS, Tegner, or IKDC scores. There was also no difference between groups for grades of osteoarthritic change for any classification system. Patients who received a BPTB graft had medial PF joint narrowing in 66.7% of cases as compared with 11.9% in those who received ACLR + ALLR (P = 0.118).

CONCLUSION

ACLR + ALLR did not increase the risk of OA in the lateral tibiofemoral compartment when compared with an isolated ACLR at medium-term follow-up. Isolated ACLR using BPTB was associated with a significantly increased risk of medial PF joint space narrowing.

REGISTRATION

NCT05123456 (ClinicalTrials.gov identifier).

Anterolateral ligament of the knee-Cadaver study in a Caucasian population

INTRODUCTION

Despite the recognized importance of the anterolateral ligament (ALL) in rotational stability of the knee, some studies still deny its role and even its existence. We studied the prevalence of the ALL in a Caucasian population, as well as its characteristics and anatomical relationships.

MATERIALS AND METHODS

The study was performed on 20 knees from 10 embalmed cadavers. A lateral approach, as described by Steven Claes, was used and the relations of the ALL with the lateral epicondyle, lateral inferior genicular artery, lateral meniscus, Gerdy's tubercle and fibular head were recorded. Its length and its width were also measured.

RESULTS

The ALL was identified in 16 knees. Its origin was at a distance inferior to 1mm posterior and proximal to the lateral femoral epicondyle and insertion within a mean distance of 2.1±0.6mm from the tibial articular surface, 20.6±1.3mm from the Gerdy's tubercle and 20.3±1.2mm from the fibular head. In all cases ALL presented mutual fibers with the lateral meniscus. The length was 35.8±4.6mm and the width was 4.2±1.3/4.9±1.0/6.5±1.5mm at its proximal, middle and distal third, respectively. No difference was found between gender and the dimensions of the ligament.

CONCLUSIONS

The ALL was found in 80% of the knees. Its origin is closely related to the lateral collateral ligament and its insertion is halfway between the fibular head and the Gerdy's tubercle. In all cases, we verified the connection between ALL and the lateral meniscus.

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.

Anterolateral ligament of the knee-Cadaver study in a Caucasian population

INTRODUCTION

Despite the recognized importance of the anterolateral ligament (ALL) in rotational stability of the knee, some studies still deny its role and even its existence. We studied the prevalence of the ALL in a Caucasian population, as well as its characteristics and anatomical relationships.

MATERIALS AND METHODS

The study was performed on 20 knees from 10 embalmed cadavers. A lateral approach, as described by Steven Claes, was used and the relations of the ALL with the lateral epicondyle, lateral inferior genicular artery, lateral meniscus, Gerdy's tubercle and fibular head were recorded. Its length and its width were also measured.

RESULTS

The ALL was identified in 16 knees. Its origin was at a distance inferior to 1mm posterior and proximal to the lateral femoral epicondyle and insertion within a mean distance of 2.1±0.6mm from de tibial articular surface, 20.6±1.3mm from the Gerdy's tubercle and 20.3±1.2mm from the fibular head. In all cases ALL presented mutual fibers with the lateral meniscus. The length was 35.8±4.6mm and the width was 4.2±1.3/4.9±1.0/6.5±1.5mm at its proximal, middle and distal third, respectively. No difference was found between gender and the dimensions of the ligament.

CONCLUSIONS

The ALL was found in 80% of the knees. Its origin is closely related to the lateral collateral ligament and its insertion is halfway between the fibular head and the Gerdy's tubercle. In all cases, we verified the connection between ALL and the lateral meniscus.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

Combined anterolateral complex and anterior cruciate ligament injury: Anatomy, biomechanics, and management-State-of-the-art

Anterior cruciate ligament (ACL) rupture typically occurs because of sudden axial loading of the knee in conjunction with a coupled valgus and rotational moment about the tibia. However, the ACL is not the only structure damaged during this mechanism of injury, and studies have shown that the anterolateral complex (ALC) of the knee is also commonly involved. Biomechanical studies have established that the ALC plays an important role as a secondary stabiliser to control anterolateral rotatory laxity (ALRL). Indeed, it has been suggested that failure to address injury to the ALC at the time of ACL reconstruction (ACLR) may increase the risk of graft failure owing to persistent ALRL. The concept of combining a lateral extra-articular procedure to augment ACLR for the treatment of ACL injury emerged with a view to decrease the failure rate of either procedure in isolation. This state-of-the-art review discusses the history of the anatomy of the ALC, the biomechanics of a variety of lateral extra-articular augmentation procedures, and provides clinical guidelines for their use in primary ACLR.

Analysis of Mechanoreceptors and Free Nerve Endings of the Transverse Carpal Ligament

Background: The treatment of carpal tunnel syndrome (CTS) by sectioning the transverse carpal ligament (TCL) is not exempt from complications. Some nerve branches may be damaged by the incision. The aim of this study is to identify and map the TCL nerve endings, serving as a guide for sectioning this structure in a zone with less nerve ending density. Methods: Ten TCLs were obtained from fresh frozen cadavers. The TCLs were measured, divided into 3 equal bands (radial, central, and ulnar), and submitted to cryostat sectioning. The sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 and confocal microscopy analysis. Results: All the specimens contained type I and type IV mechanoreceptors. Neural elements occupied 0.695 ± 0.056% of the ligament area. The density of the neural elements was greater in the radial, followed by the ulnar and central bands, with 0.730 ± 0.083%, 0.686 ± 0.009%, and 0.669 ± 0.031%, respectively. Conclusion: The present findings suggest that the region with the least potential for neural element injury during TCL release is the central third near the transition with the ulnar third. When performed distally to proximally with a slight inclination from the radial to the ulnar, this release compromises the lowest nerve element density. Topographically, the proximal limit of the release is the distal wrist crease, while the distal limit is the intersection of Kaplan cardinal line and the axis of the third webspace.

Anterior cruciate ligament rupture and associated Segond fracture: Incidence and effect on associated ligamentous and meniscal injuries

Introduction

The Segond fracture is an avulsion fracture of the lateral tibial plateau and is widely considered to be pathognomonic of anterior cruciate ligament (ACL) rupture. In addition to ACL rupture, Segond fractures have also been noted to be associated with significant intra-articular pathology such as meniscal injuries as well as extra-articular pathology such as collateral ligament injuries. This is likely due to the fact that the presence of a Segond fracture may represent increased rotatory instability. Whilst several studies have demonstrated the association of a Segond fracture with significant intra-articular pathology, there is a paucity of literature assessing if the combination of an ACL rupture and Segond fracture gives rise to higher rates of concomitant ligamentous and meniscal injuries. The primary objective of this study is to determine if patients with ACL ruptures associated with Segond fractures have higher rates of concomitant ligamentous and meniscal injury, when compared to patients with ACL ruptures without a Segond fracture.

Methods

A retrospective review of all patients who underwent ACL reconstruction in a single institution between 2014 to 2018 was conducted. A review of the patients’ demographics, operative notes, and radiographs was performed. X-rays and MRI scans were double-read by a board-certified radiologist and Orthopaedic surgeon.

Results

A total of 414 subjects were included. The incidence of Segond fracture was 2.4%. The mean age was 24.7±7.4 (range 16 to 60) years and 26.7±7.6 (range 16 to 38) years in patients with and without Segond fractures respectively. 89.9% of patients suffered a non-contact mechanism of injury, with sports injuries being most common (79.5%). There was a significantly higher rate of isolated lateral meniscus tears in patients with Segond fractures compared to those without (50% v.s. 20.8%) based on pre-operative MRI. (p<0.05) There were no other significant differences in associated ligamentous injuries.

Conclusion

The incidence of Segond fracture associated with ACL rupture is 2.4%. There is a significantly higher risk of a concomitant isolated lateral meniscus tear in ACL ruptures associated with a Segond fracture. There is no significantly higher risk of concomitant ligamentous injuries in ACL ruptures associated with a Segond fracture.

Anterior Cruciate Ligament Reconstruction Procedures Using the Iliotibial Band Autograft

The Micheli anterior cruciate ligament (ACL) procedure is a combined intra-articular and extra-articular knee stabilization technique that combines lateral augmentation with ACL reconstruction using the iliotibial band as an autograft for both aspects of the technique. Its primary indication is for ACL reconstruction in skeletally immature patients with more than 2 years of growth remaining. Studies have shown it to be effective at restoring knee biomechanics to have minimal risk of complications, including those associated with growth disturbances and a relatively low ACL graft rupture rate. Additional studies are needed to better understand the potential utilization of this technique and related modifications in the marginally skeletally immature patient, skeletally mature adolescent, adult, and revision ACL reconstruction settings.

Characteristics and Trends of the Most Cited Knee Surgery, Sports Traumatology, Arthroscopy Articles

Purpose

To compile and analyze the top 50 most frequently cited articles published in the Knee Surgery, Sports Traumatology, Arthroscopy journal.

Methods

Guidelines set by the Preferred Reporting Items for Systematic Reviews were used as the foundation for data collection and analysis. Scopus database was used to acquire the metric analyzed in the study. Once collected, the data was exported to an excel sheet in order to be organized, sorted, and analyzed in accordance with the metrics of interest.

Results

The United States was the most contributory nation with 14 publications, followed by Sweden with13 publications and Germany with eight publications. The most contributory institution was Umeå University in Vasterbottens, Sweden (8) followed by National Institute for Working Life in Stockholm, Sweden (7) and The University of Pittsburgh (5). Most publications were either Level II (19) or Level III (19) in terms of Level of Evidence. There was only one publication that was classified as a Level I paper.

Conclusion

The Journal of Knee Surgery, Sports Traumatology, and Arthroscopy has published very influential research papers as noted by the number of citations amassed by its most popular articles. KSSTA's top cited publications hail largely from major European and United States institutions and are composed of high-quality reports of mostly Level 2 and Level 3 evidence classifications.

Level of Evidence

3.

Graft choices for anterolateral ligament knee reconstruction surgery: Current concepts

The anterolateral ligament (ALL) is a primary structure of the anterolateral complex of the knee that contributes to internal rotational stability of the joint. Injury of the ALL is commonly associated with rupture of the anterior cruciate ligament. If left untreated, ALL lesions may lead to residual anterolateral rotational instability of the knee after anterior cruciate ligament reconstruction, which is a common cause of anterior cruciate ligament graft failure. The function of the ALL can be restored by lateral extraarticular tenodesis or anterolateral ligament reconstruction (ALLR). In the lateral extraarticular tenodesis procedure, a strip of the iliotibial band is placed in a non-anatomical position to restrain the internal rotation of the tibia, while in ALLR, a free graft is fixed at the insertion points of the native ALL. Gracilis and semitendinosus grafts have mainly been utilized for ALLR, but other autografts have also been suggested. Furthermore, allografts and synthetic grafts have been applied to minimize donor-site morbidity and maximize the size and strength of the graft. Nevertheless, there has been no strong evidence to fully support one method over another thus far. The present review presents a detailed description of the graft choices for ALLR and the current literature available in regard to the effectiveness and outcomes of published surgical techniques.

Anterolateral complex of the knee: State of the art

Rotatory instability of the knee represents the main reason for failure and poor clinical outcomes regarding anterior cruciate ligament (ACL) reconstruction techniques. It is now clear that the anterolateral complex (ALC) of the knee possesses a fundamental role, in association with the ACL, in controlling internal rotation. Over the past decade, ever since the anterolateral ligament has been identified and described as a distinct structure, there has been a renewed interest in the scientific community about the whole ALC: Lateral extra-articular tenodesis have made a comeback in association with ACL reconstructions to improve functional outcomes, reducing the risks of graft failure and associated injuries. Modern ACL reconstruction surgery must therefore investigate residual instability and proceed, when necessary, to extra-articular techniques, whether functional tenodesis or anatomical reconstruction.This review aims to investigate the latest anatomical and histological descriptions, and the role in rotational control and knee biomechanics of the ALC and its components. The diagnostic tools for its identification, different reconstruction techniques, and possible surgical indications are described.. In addition, clinical and functional results available in the literature are reported.

Anatomy of the anterolateral ligament of the knee joint

Despite remarkable improvements in clinical outcomes after anterior cruciate ligament reconstruction, the residual rotational instability of knee joints remains a major concern. The anterolateral ligament (ALL) has recently gained attention as a distinct ligamentous structure on the anterolateral aspect of the knee joint. Numerous studies investigated the anatomy, function, and biomechanics of ALL to establish its potential role as a stabilizer for anterolateral rotational instability. However, controversies regarding its existence, prevalence, and femoral and tibial insertions need to be addressed. According to a recent consensus, ALL exists as a distinct ligamentous structure on the anterolateral aspect of the knee joint, with some anatomic variations. The aim of this article was to review the updated anatomy of ALL and present the most accepted findings among the existing controversies. Generally, ALL originates slightly proximal and posterior to the lateral epicondyle of the distal femur and has an anteroinferior course toward the tibial insertion between the tip of the fibular head and Gerdy’s tubercle below the lateral tibial plateau.

Clinical and mechanical outcomes in isolated anterior cruciate ligament reconstruction vs additional lateral extra-articular tenodesis or anterolateral ligament reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction has been a successful treatment for ACL rupture. However ongoing rotational instability can be an issue. Several surgical techniques have been recommended to overcome this including lateral extra-articular tenodesis (LET) and more recently anterolateral ligament reconstruction (ALLR).

AIM

To compare the clinical outcomes following ACL reconstruction (ACLR) alone or ACLR with either LET or ALLR.

METHODS

A systematic review was conducted by means of four databases (MEDLINE, EMBASE, Cochrane and Clinical.Trials.Gov), and the Reference Citaion Analysis (https://www.referencecitationanalysis.com/) to identify all studies investigating either or both of LET and ALLR. The Critical Appraisal Skills Programme checklist for cohort studies was employed for critical appraisal and evaluation of all twenty-four studies which met the inclusion criteria.

RESULTS

Pooled meta-analyses illustrated that ACLR with additional LET or ALLR results in improved pivot shift test scores, compared to isolated ACLR. There was no statistically significant difference in International Knee Documentation Committee (IKDC) clinical scores with addition of either LET or ALLR. ACL re-rupture rates were compared between LET and ALLR techniques. There was a statistically significant difference between techniques, with a 1.14% rupture rate in ACLR +ALLR, and 4.03% rupture rate in ACLR + LET. Isolated ACLR re-rupture rates were 12.59%, significantly higher than when augmented with either ALLR or LET (P < 0.0001 for both groups). There were no statistical differences in pivot shift test or IKDC scores between LET and ALLR techniques.

CONCLUSION

This meta-analysis has found that use of either LET or ALLR in addition to ACLR results in improved mechanical outcomes suggesting surgeons should consider augmenting ACLR with an extra-articular procedure in patients with rotatory instability. Furthermore, both anterolateral extra articular procedures in addition to ACLR lead to reduced ACL re-rupture rates compared to isolated ACLR. Moreover, ALLR results in reduced ACL re-rupture rates, compared to LET. More research is needed to compare the two respective extra-articular procedures.

Resultado funcional do procedimento de tenodese extra-articular lateral (TEL) como complemento à reconstrução do ligamento cruzado anterior: Uma metanálise

Objectives  The aim of the present study is to systematically review and analyze the functional outcome of lateral extraarticular tenodesis (LET) procedure in addition to anterior cruciate ligament reconstruction (ACLR) in studies with a high level of evidence.

Methods  We performed a literature search for clinical studies comparing the LET method as an augmentation to ACL reconstruction with ACL reconstruction alone. The primary outcomes were the International Knee Documentation Committee (IKDC) score, the Lysholm score, and graft failures. Continuous variables were reported as means and 95% confidence intervals (CIs).

Results  Six clinical studies with 1,049 patients were included in the metaanalysis. The follow-up period was, in average, 24 months (range, 6–63 months). The addition of the LET procedure to ACLR results in better functional outcome based on the IKDC score ( p  < 0.05). Graft failure was found to be lower in the ACLR plus LET group (16 of 342 patients) compared with the ACLR-only group (46 of 341 patients) ( p  < 0.05).

Conclusion  There is high-level evidence that LET procedure in addition to ACLR is preferable in terms of functional outcome and graft failure.

The Cadaveric Studies and the Definition of the Antero-Lateral Ligament of the Knee: From the Anatomical Features to the Patient-Specific Reconstruction Surgical Techniques

Cadaver studies represented a milestone in surgical orthopaedic research, and still today they play a crucial role in the achievement of new knowledge about joint disease behaviour and treatment. In this review, an overview of the cadaver studies available in the literature about the anatomy, role, and treatment of the antero-lateral ligament (ALL) of the knee was performed. The aim of the review was to describe and gain more insight into the part of in vitro study in understanding knee joint anatomy and biomechanics, and in developing surgical reconstruction techniques. The findings of the review showed that cadaver studies had, and will continue to have, a key role in the research of knee joint biomechanics and surgical reconstruction. Moreover, they represent a powerful tool to develop and test new devices which could be useful in clinical and surgical practice.

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.

Clinical outcomes of contemporary lateral augmentation techniques in primary ACL reconstruction: a systematic review and meta-analysis

PURPOSE

The purpose of this investigation was to systematically review the contemporary literature to determine if a lateral augmentation (LA) added to an Anterior Cruciate Ligament Reconstruction (ACLR) provides better clinical and patient reported outcomes compared to an isolated ACLR.

METHODS

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) criteria. Two authors independently conducted an electronic search using MEDLINE® and Embase® on February 6^th, 2021 for level I-III randomized controlled trials (RCT) and prospective cohort studies without randomization, published after 2012 and with a minimum of two year follow-up. Publications were included when they reported on the objective knee stability examination, patient reported outcome scores, return to sports or graft rupture rate of any type of primary, isolated ACLR compared to ACLR combined with any type of LA.

RESULTS

A total of 11 studies that reported on a combined total of 1892 unique patients were eligible for data extraction, including five RCTs and six prospective cohort studies. In 6 studies, an Anterolateral Ligament reconstruction (ALLR) was the LA of choice, while the 5 other publications used different types of Lateral Extra-articular Tenodesis (LET). A significant reduction in graft ruptures was found in patients treated with ACLR + LA (3%) compared to isolated ACLR (12%). Rotational laxity was significantly higher in isolated ACLR (14%) compared to ACLR + LA (6%). Addition of a LA reduced anterior translation when assessed via instrumented laxity testing. No significant difference was found in the patient reported outcome scores (IKDC and Tegner) between both patient groups, except for the Lysholm Score which was significant in favour of the ACLR + LA group.

CONCLUSION

Combination of a primary ACLR with a LA can significantly reduce the risk of graft rupture and provide better rotatory stability, without jeopardizing patient reported outcomes.

LEVEL OF EVIDENCE

Level III, Systematic Review of Level I, II and III studies.

MRI Evaluation of Anterolateral Ligament of the Knee: A Cross-Sectional Study in Malaysia

Introduction

After detailed anatomical delineation of the anterolateral ligament (ALL) of the knee, there is a surge in research on this anatomical structure. Owing to the anatomical variation and lack of experience in the identification of this structure, magnetic resonance (MR) evaluation of the ALL produces mixed results. It was aimed to evaluate the ALL using the routinely performed MR imaging of the knee and to determine any associated factors with ALL injuries.

Materials and methods

Thirty-six MR images of the knee from 31 patients from January 1, 2017, to June 30, 2017, are evaluated. MR sequences performed include T1-weighted, T2-weighted, proton density (PD), and PD fat saturation (FS). All MR images were double-read by two authors and approved by a consultant radiologist with more than 20 years of radiological experience. The ALL was divided into three portions: femoral, meniscal, and tibial, and the ALL was considered fully visualized when all three portions were seen on MR images.

Results

At least a portion of the ALL was visualized in 27 scans (75%), and it was fully visualized in 20 scans (55.6%). The femoral portion was the most commonly identified (75%), followed by the meniscal portion (69.4%) and the tibial portion (58.3%). ALLs were best visualized on coronal view in PD FS with the lateral inferior genicular artery as a guide to locate the bifurcation of the meniscal and tibial components.

Conclusion

The ALL can be visualized in routine 1.5-T MR imaging, either full delineation (55.6%) or partially visualized (75%). It is best characterized via a PD-weighted sequence with fat saturation on the coronal plane. The ALL injury was associated with an anterior cruciate ligament (ACL) injury.

Adolescents show a lower healing rate of anterolateral ligament injury and a higher rotational laxity than adults after anterior cruciate ligament reconstruction

BACKGROUND

This study aimed to compare anterolateral ligament (ALL) injuries in anterior cruciate ligament (ACL) ruptures, as well as ALL healing and clinical outcomes following ACL reconstruction between adolescents and adults.

METHODS

This retrospective study involved 98 patients who underwent ACL reconstruction. They were divided into two groups according to age: group A (adolescents, 16-20 years of age; n = 49) and group B (adults, 21-45 years of age; n = 49). Subjective scores including ACL-Return to Sport after Injury (ACL-RSI) scale and objective tests were assessed. Follow up magnetic resonance imaging (MRI) and second-look arthroscopy was conducted at 1-year and 2-year follow up, respectively.

RESULTS

Good healing rate of ALL was higher in adults than in adolescents (P = 0.048). Graft tension and synovial coverage showed no significant differences between two groups. Group A showed a higher rate of high-grade pivot shift and a lower ACL-RSI at last follow up than group B (P = 0.126 and P = 0.016). Poor healing of ALL was significantly associated with lower ACL-RSI and failure to return to sports (P < 0.001 and P = 0.001). Re-rupture of the ACL graft was found in four (8.2%) and one (2.0%) of group A and B, respectively.

CONCLUSIONS

Adolescents showed a lower healing rate of ALL, a lower ACL-RSI, a higher rate of high-grade pivot shift than adults. Moreover, poor healing of ALL was significantly associated with a lower ACL-RSI and failure to return to sports. We suggest that adolescents need to pay more attention to the presence of ALL injury.

Prevalence and morphometric characteristics of the anterolateral ligament of the knee in a sample of Colombian human cadavers

Introduction: The anatomy of the knee and its ligaments is clearly described in the relevant literature; however, several studies have found new structures associated with this joint, such as the anterolateral ligament (ALL) of the knee. The prevalence of this ligament varies a lot around the world, and studies addressing this topic in Colombian population are scarce. Objective: To determine the prevalence of ALL and its morphometric characteristics in a sample of Colombian human cadavers. Materials and methods: Cross-sectional study in which the knee joints of 15 human cadavers were dissected and analyzed. In order to ensure the integrity of anatomical structures such as ligaments and tendons, specimens should have not undergone previous dissections, so only 29 knees were included for analysis. The presence of the ligament was verified, and the proximal and distal insertion site, as well as its length and width, were established through the dissection. Results: The prevalence of ALL was 24.13%, as it was identified in 7 of the 29 dissected knees (4 left and 3 right knees). The average length and width of the ALLs found were 37.5mm (range: 24-52.4mm) and 3.9mm (range: 2.6-6mm), respectively. Conclusions: This study allowed confirming the presence of the ALL in Colombian population, although with a lower prevalence than that described in countries such as France, India, China, USA and Brazil. In turn, its morphometric characteristics were similar to those reported worldwide, since the average length and width found here are consistent with those described in the literature.

Association Between Radiological Evidence of Kaplan Fiber Injury, Intraoperative Findings, and Pivot-Shift Grade in the Setting of Acute Anterior Cruciate Ligament Injury

BACKGROUND

Biomechanical studies have suggested that the Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotation of the knee. There is a paucity of clinical information on whether injury to the KF in the setting of anterior cruciate ligament (ACL) rupture contributes to increased rotatory laxity of the knee.

PURPOSE/HYPOTHESIS

The purpose was to evaluate the association among radiological evidence of KF injury, intraoperative arthroscopic findings, and grade of pivot shift at the time of ACL reconstruction (ACLR). It was hypothesized that KF injury would be associated with increased injury to the lateral compartment of the knee and a higher grade of pivot shift.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective magnetic resonance imaging (MRI) analysis was conducted on 267 patients with ACL-injured knees who underwent primary ACLR. Patients who had MRI and surgery within 60 days of injury were included (mean age, 23.6 years); there were 158 (59.2%) male patients. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. Associations were made among MRI findings, intraoperative findings, and grade of pivot shift with the patient examined under anesthesia at the time of ACLR. A comparison was made between patients with and without radiological evidence of KF injury.

RESULTS

The prevalence of KF injury was 17.6% (47/267 patients). Arthroscopic evidence of lateral meniscal injury was associated with KF injury (KF intact, 31%; KF injured, 55%; P = .010). The majority of patients in the intact and injured KF groups had a grade 2 pivot shift (75% and 70%, respectively). A minority had grade 3 pivot shift: 5% in the intact group versus 6.4% in the injured group. There was no association between radiological evidence of KF injury and pivot-shift grade (P = .600).

CONCLUSION

In acute ACL injury, KF injuries were not very common (17.6%), and the rate of grade 3 pivot shift was low (5.2%). When present, KF injuries were not associated with a higher-grade pivot shift. However, there was an association between KF injury and lateral meniscal tears identified at the time of ACLR. The role of KFS in controlling anterolateral rotatory laxity in the acute ACL injury in the clinical setting may be less evident when compared with the biomechanical setting.

3T MRI-based anatomy of the anterolateral knee ligament in patients with and without an ACL-rupture: Implications for anatomical anterolateral ligament reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) rupture is often accompanied by an injury to the anterolateral ligament (ALL) of the knee. Detailed knowledge of the ALL attachments in ACL-ruptured patients is essential for an anatomical ALL reconstruction to avoid knee over-constraint and successfully treat the residual rotational instability. The aim of the present study was to investigate the three-dimensional (3D), topographic anatomy of the ALL attachment in both ACL-ruptured and ACL-intact patients using 3 Tesla magnetic resonance imaging (3T MRI).

METHODS

In the present, retrospective case-control study, the magnetic resonance images of 90 knees with an ACL-rupture and 90 matched-controlled subjects, who suffered a non-contact knee injury without an ACL-rupture, were used to create 3D models of the knee. The femoral and tibial ALL footprints were outlined on each model, and their position was measured using an anatomical coordinate system.

RESULTS

The femoral origin of the ALL was located 4.9 ± 2.8 mm posterior and 3.8 ± 2.4 mm proximal to the lateral epicondyle in a non-isometric location in control subjects. In ACL-ruptured patients, it was located in a more posterior and distal, at 6.0 ± 1.9 mm posterior and 2.4 ± 1.7 mm proximal to the lateral epicondyle (p < 0.01), also in a non-isometric location. No difference was found in the tibial ALL insertion between groups.

CONCLUSION

The femoral ALL origin was significantly different in ACL-ruptured patients compared to ACL-intact patients. The recommended femoral tunnel position for the anatomical ALL reconstruction, does not represent the femoral ALL origin in the ACL-ruptured knee.

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.

Correlation Between the Thickness of Anterolateral Ligament and Lateral Collateral Ligament of the Knee

Background

Persistent anterolateral rotatory instability (ALRI) following the anterior cruciate ligament (ACL) reconstruction has led to a renewed interest in defining the role of anterolateral complex (ALC) of the knee.

Methods

We explored the anterolateral corner of 34 cadaveric knees to define the anterolateral ligament (ALL) in all its dimensions and measured the thickness of lateral collateral ligament (LCL) at the lateral meniscus level (tLCL) in ALL-intact and ALL-deficient knees.

Results

ALL was present in 27/34 (79%) of the knees. We found complete ALL in 13 cadavers bilaterally. ALL was absent bilaterally in three cadavers; it was present on one side and absent contralaterally in one cadaver. In ALL-intact knees, the average tLCL was 2.05 mm, whereas, in ALL-deficient knees, it was 2.57 mm. This difference in tLCL was statistically significant.

Conclusions

Our study adds new data to the recent voluminous research on ALL. We have examined the correlation between the thickness of ALL and LCL and documented alterations in the thickness of LCL in ALL-intact knees. These findings would help in designing reconstructive procedures for the combined ACL injury with ALRI.

Microstructural and Mechanical Properties of the Anterolateral Ligament of the Knee

BACKGROUND

The variable anatomy and controversy of the anterolateral ligament (ALL) reflect the complex relationship among the anterolateral knee structures.

PURPOSE/HYPOTHESIS

The purpose was to quantify the microstructural and mechanical properties of the ALL as compared with the anterolateral capsule (ALC) and lateral collateral ligament (LCL). The primary hypotheses were that (1) there is no difference in these properties between the ALL and ALC and (2) the LCL has significantly different properties from the ALL and ALC.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The LCL, ALL, and ALC were harvested from 25 cadaveric knees. Mechanical testing and microstructural analyses were performed using quantitative polarized light imaging. The average degree of linear polarization (AVG DoLP; mean strength of collagen alignment) and standard deviation of the angle of polarization (STD AoP; degree of variation in collagen angle orientation) were calculated.

RESULTS

Linear region moduli were not different between the ALC and ALL (3.75 vs 3.66 MPa, respectively; P > .99). AVG DoLP values were not different between the ALC and ALL in the linear region (0.10 vs 0.10; P > .99). Similarly, STD AoP values were not different between the ALC and ALL (24.2 vs 21.7; P > .99). The LCL had larger modulus, larger AVG DoLP, and smaller STD AoP values than the ALL and ALC. Of 25 knee specimens, 3 were observed to have a distinct ALL, which exhibited larger modulus, larger AVG DoLP, and smaller STD AoP values as compared with nondistinct ALL samples.

CONCLUSION

There were no differences in the mechanical and microstructural properties between the ALL and ALC. The ALC and ALL exhibited comparably weak and disperse collagen alignment. However, when a distinct ALL was present, the properties were suggestive of a ligamentous structure.

CLINICAL RELEVANCE

The properties of the ALL are similar to those of a ligament only when a distinct ALL is present, but otherwise, for the majority of specimens, ALL properties are closer to those of the capsule. Variability in the ligamentous structure of the ALL suggests that it may be more important in some patients than others and reconstruction may be considered in selective patients. Further study is needed to better understand its selective role and optimal indications for reconstruction.

Lateral collateral ligament and anterolateral ligament of the knee - A morphological analysis with orthopedic significance

BACKGROUND

The lateral collateral ligament (LCL) is the chief stabilizer of the lateral aspect of the knee to varus forces. Studies have confirmed the function of the anterolateral ligament (ALL), which improves the lateral knee stability by preventing excessive internal tibial rotation. Clinically, a persistent instability following anterior cruciate ligament reconstruction may be due to damage to the anterolateral structures. The finding has created a novel interest in anterolateral extra-articular operations.

METHODS

This observational, cross-sectional study involved 42 dissected adult knees. The variations in morphology and morphometry of the LCL were identified and classified. The prevalence and the variabilities in the ALL were also noted.

RESULTS

The variations in the shape of the LCL were classified into four types: (1) cord, (2) band, (3) mixed, and (4) inverted Y shaped, with a frequency of 69.04, 26.20, 2.38, and 2.38% of specimens, respectively. The cord type measured 50.4 ± 2.7 mm in length and 5 ± 0.9 mm in width. In comparison, the band type measured 50.1 ± 4.2 mm in length and 9 ± 1.6 mm in width. The ALL was identified in four (9%) of the specimens with a mean length of 35 ± 0.9 mm. Two types of ALL were observed, membranous wideband and distinct cord-like ALL.

CONCLUSION

The anatomy of the lateral structures of the knee is inconsistent. The study has attempted to classify the different shapes of the LCL along with the frequency and prevalence of the ALL. Orthopedic surgeons and radiologists must note the LCL morphology and prevalence of the ALL due to their clinical implications.

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.

Research on the Anterolateral Ligament of the Knee: An Evaluation of PubMed Articles From 2010 to 2019

Background:

The anterolateral ligament (ALL) of the knee remains a topic of interest. All aspects of the ligament, including its anatomy, biomechanics, imaging, and clinical importance, are areas for research among knee surgeons.

Purpose:

To evaluate the trends in research on the ALL of the knee, as indicated by studies indexed in PubMed from 2010 to 2019.

Study Design:

Cross-sectional study.

Methods:

We searched PubMed for article titles from January 1, 2010, to December 31, 2019, that included the term “anterolateral ligament.” The initial search was performed with the terms “anterolateral ligament AND knee” and “anterolateral ligament NOT knee.” Next, we performed a search using “anterolateral complex OR anterolateral reconstruction OR lateral extra-articular tenodesis” to avoid missing any studies. A bibliometric evaluation was performed for the search results, and we noted the characteristics of the most cited articles in PubMed.

Results:

Published studies on the ALL peaked in 2017, with 56 studies, and then declined from 2017 to 2019. The 3 leading journals with articles on the ALL were Arthroscopy; Knee Surgery, Sports Traumatology, Arthroscopy; and The American Journal of Sports Medicine. Cadaveric anatomic, cadaveric biomechanical, and clinical imaging studies of the ALL were the most common types of studies published from 2010 to 2019. Clinical studies on the ALL consisted of 18 articles, with the majority displaying a low level of evidence.

Conclusion:

Cadaveric anatomic/histological, cadaveric biomechanical, and clinical imaging studies of the ALL were the most commonly published studies from 2010 to 2019. More clinical outcome studies with a high level of evidence are needed to increase the supporting data for the future practice of ALL reconstruction.

Timing of magnetic resonance imaging affects the accuracy and interobserver agreement of anterolateral ligament tears detection in anterior cruciate ligament deficient knees

Purpose

We aimed to identify the anterolateral ligament (ALL) tears in anterior cruciate ligament (ACL)-deficient knees using standard 1.5-Tesla magnetic resonance imaging (MRI).

Methods

We included all patients who underwent primary ACL reconstruction at our center between 2012 and 2015. Exclusion criteria included patients with multiple ligament injuries, lateral collateral ligament, posterolateral corner, and infections, and patients who underwent MRI more than 2 months after their injury. All patients (n = 148) had ACL tears that were subsequently arthroscopically reconstructed. The magnetic resonance (MR) images of the injured knees performed within 2 months of injury were reviewed by a musculoskeletal radiologist and an orthopedic surgeon. The patients were divided into two groups. The first group of patients had MRI performed within 1 month of injury. The second group of patients had MRI performed 1–2 months after the index injury. Both assessors were blinded and the MR mages were read separately to assess the presence of ALL, presence of a tear and the location of the tear. Based on their readings, interobserver agreement (kappa statistic (K)), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were compared.

Results

The ALL was identified in 100% of the patients. However, there was a discrepancy of up to 15% in the identification of tear of the ALL. In the first group in which MRI scans were performed within 1 month of injury, the ALL tear was identified by the radiologist in 92% of patients and by the surgeon in 90% of patients (Κ = 0.86). In the second group in which MRI scans were performed within 1–2 months of the injury, the ALL tear was identified by the radiologist in 78% of patients and by the surgeon in 93% of patients (K = 0.62).

Conclusion

The ALL can be accurately identified on MRI, but the presence and location of ALL tear and its location cannot be reliably identified on MRI. The accuracy in identification and characterization of a tear was affected by the interval between the time of injury and the time when the MRI was performed.

Level of evidence

Diagnostic, level IIIb, retrospective.

Comparative Analysis of Sagittal-Plane Radiographic Landmarks Used to Identify the Femoral Attachments of Lateral Knee Structures

PURPOSE

To compare previously described radiographic parameters for the localization of the lateral knee (LK) structures, including the popliteal tendon (Pop), anterolateral ligament (ALL), and lateral collateral ligament (LCL), to determine which method best estimates the femoral attachment of each LK structure.

METHODS

Twenty-nine human cadaveric knee specimens were carefully dissected to identify the LCL, ALL, and Pop. The femoral attachment for each structure was labeled with a radiopaque bead. LK radiographic images were obtained using fluoroscopy. Two radiographic approaches were used to identify each LK structure (Pop-A, Pop-B, LCL-A, LCL-B, ALL-A, and ALL-B) via previously published methods based on radiographic landmarks including the posterior femoral cortex and the Blumensaat line. The identification of radiographic landmarks was performed at 2 different time points by 2 different surgeons to determine the Pearson correlation between values, as well as interobserver and intraobserver reliability and reproducibility. The paired t test was conducted to compare the distance between the actual attachment site (as determined by the bead location) and the 2 radiographically identified estimations of attachment locations.

RESULTS

For the LCL, the mean difference between the actual location and the estimated location via application of the LCL-B method (5.0 ± 2.4 mm) was significantly less than that estimated using the LCL-A method (8.2 ± 3.3 mm, P < .0001). Likewise, the Pop-B (5.7 ± 2.0 mm) and ALL-B (9.3 ± 4.5 mm) methods were shown to have smaller differences between the actual and estimated femoral attachment sites of the Pop insertion and ALL insertion, respectively (P < .0001). Methods for estimating the ALL femoral origin were the worst among the LK structures analyzed, with 90% of estimated values greater than 5 mm from the anatomic origin. Interobserver and intraobserver intraclass correlation coefficients were 0.785 or higher.

CONCLUSIONS

Previously described radiographic methods for localization of the femoral attachment sites of the LK structures resulted in estimated locations that were significantly different from the locations of the radiographic beads placed at the anatomic femoral attachment sites of these structures. Therefore, radiographic methods used to localize the femoral attachments of the LK structures may not be reliable.

CLINICAL RELEVANCE

This study shows the variability of the anatomy of the LK structures and the lack of reproducible radiographic criteria to identify these structures. As a result, there will be decreased reliance on radiographic landmarks to identify the placement of femoral grafts and fixation when reconstructing these structures.

The anterolateral ligament in acute knee trauma: patterns of injury on MR imaging

OBJECTIVE

To delineate the spectrum of traumatic knee injuries associated with injury of the anterolateral ligament of the knee (ALL).

MATERIALS AND METHODS

A retrospective review of 200 MRI scans undertaken for acute knee trauma was performed. In each scan, the ALL was scored as normal, sprained or torn. The menisci, ligaments and tendons of each knee were also assessed.

RESULTS

The mean age was 27.4 years (range, 9-69 years), and 71.5% (n = 143) of the patients were male. The anterolateral ligament (ALL) was graded as ruptured in 17 cases (8.5%), sprained in 58 cases (29%), normal in 116 cases (58%) and not visible in 9 cases (4.5%). Of cases with injury of the ALL (n = 75), there was associated injury of the anterior cruciate ligament (ACL) in 61 cases, medial collateral ligament (MCL) in 51 cases, popliteofibular ligament (PFL) in 29 cases, medial meniscus in 29 cases, lateral meniscus in 24 cases, lateral collateral ligament in 9 cases, posterior cruciate ligament in 8 cases, biceps femoris in 5 cases, popliteus tendon in 4 cases and fluid or oedema was seen adjacent to the iliotibial band in 59 cases. No cases of isolated ALL injury were seen.

CONCLUSIONS

ALL injury is not uncommon in acute knee trauma and is typically associated with significant internal derangement of the knee, especially anterior cruciate ligament rupture, ITB sprain, medial collateral ligament injury, meniscal tears and injury to the popliteofibular ligament.

Predictive factors for failure of anterior cruciate ligament reconstruction via the trans-tibial technique

INTRODUCTION

Factors for graft failure after trans-tibial (TT) ACL reconstruction, including anterolateral ligament (ALL) injury and degree of synovialization, remain unclear. This study is to evaluate the risk factors for graft failures after TT ACL reconstruction including ALL injury and synovialization.

MATERIALS AND METHODS

A total 391 patients who underwent primary TT ACL reconstruction were included. Failure was defined as greater than grade 2 laxity on the Lachman or pivot shift tests or 5 mm of anterior translation on stress radiograph. After applying inclusion/exclusion criteria, 31 patients with failure were categorized as group 1 and 89 patients without failure were categorized as group 2. Chi-square test and Cox proportional hazard analyses were performed.

RESULTS

Preoperatively, 64 patients had ALL injuries (53.3%), 58 had medial meniscal (MM) tears (48.3%), and 62 had lateral meniscal (LM) tears (51.6%). Ninety-three patients (77.5%) had acute injuries and 27 had chronic injuries as per 6-weeks duration. Significant risk factors for failure were LM tear (hazard ratio [HR], 4.018; 95% confidence interval [CI] 1.677-9.629; p = 0.002), chronicity (HR, 6.812; 95% CI 2.758-16.824; p = 0.000), presence of ALL injury (HR, 3.655; 95% CI 1.442-9.265; p = 0.006), and poor synovialization (HR, 3.134; 95% CI 1.298-7.566; p = 0.011) in Cox proportional hazard analysis. If combined MM and LM tears were found, an increased risk of failure was also identified (combined tears: HR, 3.951; 95% CI 1.754-8.901; p = 0.001/preoperative high-grade laxity: HR, 4.546; 95% CI 1.875-11.02; p = 0.001).

CONCLUSION

Chronic ACL injuries, meniscus tear, preoperative ALL injuries, preoperative high-grade laxity and poor synovialization are significant risk factors. Therefore, these factors should be carefully assessed and properly treated in TT ACL reconstruction.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Truly Existing or Hyped up? Unravelling the Current Knowledge Regarding the Anatomy, Radiology, Histology and Biomechanics of the Enigmatic Anterolateral Ligament of the Knee Joint

Ever since its description, anterolateral ligament (ALL) of the knee joint remains as the hotspot of controversies. Though it has been described under various descriptions, the structure gained its limelight when it was christened as anterolateral ligament by Claes in 2013. The main reason for the controversies around it is the lack of concrete evidences regarding its attachments, morphology, biomechanical aspects and radiological appearance. Similarly the role of ALL in pivot shift phenomenon also remains as a point of debate. The advocates of ALL suggest that because of its ability to modulate internal rotation and attachment to the lateral meniscus, ALL contributes to the pivot shift phenomenon. Similarly, the orientation of ALL stands as the reason for varied documentation with respect to imaging techniques. With the growing body of evidence, it is imperative to fix our stand regarding the structure because, if found to be morphologically persistent, it can be used for concomitant anterolateral stabilization along with anterior cruciate ligament reinforcement surgeries. The present review tries to systematically review the anatomy, variations in classifications, descriptions, histology, radiology and biomechanical features of ALL. At the end of the review, we would like to find the answer for the question: Is ALL a distinct ligamentous structure located at the anterolateral aspect of the knee? What is the contribution of it to the tibial internal rotation stability?

Computed tomography (CT), X-ray, and MRI evaluation of two anterolateral knee reconstruction techniques: lateral extra-articular tenodesis (LET) and the anterolateral ligament (ALL) reconstruction

The anterolateral ligament (ALL) and capsule of the knee are anatomical structures involved in rotational stability and pivot-shift control. As such, it has been demonstrated that the extra-articular anterolateral procedures improve clinical outcome when performed as an augmentation of the anterior cruciate ligament (ACL) reconstruction in specific groups of patients. This review describes the postoperative imaging findings of two techniques used to perform these procedures, using magnetic resonance imaging (MRI), computed tomography (CT), and radiography. The first technique described is the lateral extra-articular tenodesis (LET), which uses a strip of the iliotibial band that is harvested, passed underneath the lateral collateral ligament (LCL) and fixed posterior, and proximal to the lateral femoral epicondyle (LFE), preserving ITB insertion on Gerdy's tubercle. The second technique described is the ALL reconstruction, a procedure that attempts to recreate the anatomy of the ALL, using most often a gracilis autograft. In this procedure, femoral fixation is performed proximal and posterior to the LFE, and tibial fixation is slightly distal to the joint line, halfway from Gerdy's tubercle to the fibular head. The main objective of this review is to provide an overview of the postoperative imaging aspects of these two procedures with MRI, CT, and radiography and to describe possible complications. As they become more common, it is important for the radiologist and the orthopedic surgeon to understand their particularities in combination with the already well-known ACL reconstruction.

Radiological Identification of Injury to the Kaplan Fibers of the Iliotibial Band in Association With Anterior Cruciate Ligament Injury

BACKGROUND

Recent biomechanical studies have demonstrated that the Kaplan fibers (KFs) of the iliotibial band play a role in the control of anterolateral rotation of the knee. However, controversy exists regarding whether the KFs are injured in conjunction with anterior cruciate ligament (ACL) injury.

PURPOSE

To establish the prevalence of radiological injury to the KFs in the ACL-injured knee; to evaluate the effect of the time interval between injury and magnetic resonance imaging (MRI) on diagnosis of KF injury; and to assess for any association between KF injury and other qualitative radiological findings.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

Preoperative MRI scans were reviewed for 161 patients with ACL injury. Specific diagnostic criteria were developed and applied to identify KF injury. Chi-square testing was performed to look for associations among KF injury, the time from injury to MRI, and associated radiological knee injuries.

RESULTS

Radiological evidence of KF injury was identified in 30 (18.6%) patients. The diagnosis of KF injury was higher in patients who had MRI scans performed within 90 days of injury as compared with ≥90 days after injury (23.7 vs 6.4%; P = .010). Patients with an MRI diagnosis of KF injury had significantly higher rates of lateral meniscal injury (40% vs 18%; P = .007), posteromedial tibial bone marrow edema (73% vs 44%; P = .003), and injury to the lateral collateral ligament (13% vs 3%; P = .019) or medial collateral ligament (23% vs 8%; P = .019).

CONCLUSION

The prevalence of injury to the KF in patients with ACL injury as diagnosed by MRI was relatively low (18.6% of patients). However, the time interval from injury to MRI was relevant to diagnosis, with significantly higher rates of injury identification in patients with early (within 90 days) versus delayed (≥90 days) MRI. KF injury was associated with higher rates of injury to the lateral meniscal and collateral ligaments, as well as posteromedial tibial bone bruising.

Combined Anterior Cruciate Ligament Reconstruction and Lateral Extra-Articular Tenodesis in Skeletally Immature Patients: Surgical Technique

Pediatric anterior cruciate ligament (ACL) reconstructions have a relatively high risk for re-rupture, and a low proportion of these patients report a successful return to sport. With an increasing emphasis on youth participation in pivoting sports, the incidence of these injuries has increased in recent years. A reappreciation of lateral extra-articular stabilizing procedures in high-risk adult populations who undergo ACL reconstruction has demonstrated potential improved outcomes for vulnerable ACL reconstructions. However, the open status of the pediatric physes makes the use of these procedures more challenging. Therefore, the purpose of this Technical Note is to describe the current authors' surgical technique for a combined ACL reconstruction with a lateral extra-articular tenodesis for these high-risk patients with open physes.

Magnetic Resonance Imaging Evaluation of the Anterolateral Ligament and the Iliotibial Band in Acute Anterior Cruciate Ligament Injuries Associated With Segond Fractures

PURPOSE

To evaluate the magnetic resonance imaging (MRI) characteristics of Segond fractures, including the structures attached to the avulsed fragment, the integrity of anterolateral ligament (ALL) and iliotibial band (ITB), and fragment size and location.

METHODS

This was a retrospective, cross-sectional study with MRI scans from 2016 to 2019 with the term "Segond" in the reports, signs of acute trauma, and a bony anterolateral tibial avulsion (Segond) fracture. Two experienced observers accessed images to evaluate fragment dimensions (anteroposterior, mediolateral, and craniocaudal) and distances from anatomic landmarks (Gerdy's tubercle, articular surface, and posterolateral tibial corner). ALLs and ITBs also were evaluated, both for integrity and for attachment to the avulsed bony fragment. Data were statistically evaluated for significant correlations.

RESULTS

Forty-eight knee MRIs of patients suffering from a combined anterior cruciate ligament and Segond injury were evaluated. The ALL presented with edema in 28 cases (58.3%) and was torn in 3 cases (6.3%). The ALL was attached to the bone fragment in all cases and the ITB also was attached in 25 cases (52.1%). Receiver operating characteristic curves also demonstrated that the larger each of the dimensions and the volume of the fragment, the greater the probability of ITB fibers being inserted. Also, the narrower the distance from the fragment to the center of Gerdy's tubercle, the greater the probability of iliotibial band fibers being attached. Interobserver correlation varied from 0.87 to 0.97 for all measurements.

CONCLUSIONS

In all combined ACL injuries and Segond fracture MRI cases, the complete ALL inserted on the avulsed bony fragment, whereas the posterior part of the ITB was only attached in 52.1% of the cases. Segond fracture fragment size was predictive for the structures attached to it. The ALL was abnormal in 64.5% of cases and presented a clear discontinuity in 6.3%.

LEVEL OF EVIDENCE

Case Series, Level IV.

A Randomized Controlled Trial of Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction With and Without Lateral Extra-articular Tenodesis: 19-Year Clinical and Radiological Follow-up

BACKGROUND

Arthroscopic anterior cruciate ligament (ACL) reconstruction (ACLR) with a bone-patellar tendon-bone graft (BTB) is a reliable surgical option for the control of anterior knee laxity after ACL injury. The addition of a lateral extra-articular tenodesis (LET) may improve control of rotation knee laxity and improve short-term graft survival in high-risk patients.

PURPOSE

The aims of this study were to compare long-term patient-reported outcomes, graft survival, and risk of osteoarthritis between ACLR with and without LET.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

This study included 121 consecutive knees (120 patients) presenting to a single center with an ACL rupture between 1998 and 1999. In total, 61 knees were randomized to an isolated BTB ACLR, and 60 knees were randomized to a BTB ACLR with an extra-articular lateral tenodesis with gracilis tendon (modified Lemaire).

RESULTS

Eighty knees in 79 patients (66%) were available for follow-up at a postoperative mean of 19.4 years (range, 19-20.2). Of those patients, 43 had a clinical examination and completed patient-reported outcome questionnaires, and the other 37 patients were evaluated through the questionnaires alone. Standard radiographs were available for 45 patients and laximetry (TELOS) for 42 patients. Mean subjective International Knee Documentation Committee score at last follow-up was 81.8, and no differences were noted between the BTB and BTB-LET groups (P = .7). Two-thirds of patients were still participating in pivoting sports. A total of 17 knees (21%) experienced a graft failure, 5 of which (6%) underwent revision ACLR. There was no significant difference in graft failure risk between the BTB group (29%) and the BTB-LET group (13%; P = .1). Lateral tibiofemoral osteoarthritis was significantly more frequent in the BTB-LET group (59%) as compared with the BTB group (22%; P = .02). Lateral compartment osteoarthritis was correlated with partial lateral meniscectomy.

CONCLUSION

There were no significant differences in long-term patient-reported outcomes after ACLR with or without an LET. LET may increase the risk of lateral compartment osteoarthritis at long-term follow-up. There was a trend toward decreased graft failure risk with the addition of LET but this study was underpowered to assess this outcome.

The role of anterolateral augmentation in primary ACL reconstruction

The anterolateral soft tissue envelope of the knee has long been recognised as a key stabilising structure. Once the mainstay of operative management of anterior cruciate ligament (ACL) rupture, interest in the area fell away with the advent of intraarticular arthroscopic reconstruction. Renewed interest in these structures together with cadaveric data evidencing the potential for restoration of near normal knee biomechanics following ACL and anterolateral soft tissue reconstruction has driven current concepts and development of operative techniques. Options for current anterolateral augmentation techniques in primary ACL reconstruction plus patient selection considerations are reviewed, together with an outlook at future research key to development of this area.