The anatomy of the anterolateral structures of the knee - A histologic and macroscopic approach

ACL plus ALL reconstruction restores normal knee stability and does not lead to lateral pain or signs of lateral overstrain

ACL rupture is a common injury in recreational and professional athletes. Most ACL tears occur in combination with an ALL lesion. Combined reconstruction of the ACL and ALL reduces re-rupture rates by up to 3.1 times compared to isolated ACL reconstruction using hamstring tendons; however, it has not yet been established as the surgical standard. The purpose of this study was to investigate if patients benefit from ACL+ALL reconstruction in terms of translation and rotation stability, return to activity and return to sport, as well as to assess any potential negative effects of this technique.This is a multicentric study of retrospectively collected patients who were followed up 12.7 months postoperatively. The patient sample consisted of 55 patients (group 1: n=29, Munich/Germany, ACL+ALL, femoral ALL fixation with interference screw, and group 2: n=26, Bolzano/Italy, ACL+ALL, femoral ALL-fixation with SwiveLock). Clinical outcomes were evaluated through instrumental measurements with two different devices to assess translational anteroposterior and rotational stability and through patient-reported outcome measures (Lysholm Score, Activity Rating Scale, Tegner Score, VAS (PROMs)).A total of 55 patients (mean (± SD) age: 24.7 ± 7.8 years) with a mean follow-up of 12.7 ± 1.5 months were included. The mean anterior translation of all operated (ACL+ALL) knees was 3.2 ± 1.1 mm and was not significantly different from the values of the non-operated knees (2.6 ± 1.0 mm). The results of the anterior drawer test in internal rotation were 3.3 ± 1.1 mm for the operated knee vs. 2.7 ± 1.0 mm for the non-operated knee (p=0.0014). There were no further significant differences between the operated and non-operated knee regarding translation or internal and external rotation. The mean value for pain on the lateral side of the knee was 1.1 ± 1.3 on the VAS 0-10 pain scale. All other PROMs showed no relevant differences between pre-injury and post-operative.ALL reconstruction restores the function of the anterolateral ligament of the knee. In this study, knee joint stability regarding anteroposterior translation and rotation showed values almost identical to those of the healthy non-operated contralateral knee. It leads to excellent patient outcomes with near pre-injury levels regarding the relevant PROMs. In particular, combined reconstruction did not result in any clinically significant negative side-effects such as pain on the ALL incision site or signs of overstrain in the lateral knee.

Indications for Lateral Extra-articular Tenodesis in Anterior Cruciate Ligament Reconstruction: A Systematic Review

BACKGROUND

The anterior cruciate ligament (ACL) is a major sagittal plane stabilizer of the knee joint. Even if anterior laxity can be brought under control by utilizing modern surgical techniques, internal rotational instability may not always be controlled adequately. Various surgical techniques are used to prevent this coronal or rotational instability, such as lateral extra-articular tenodesis (LET). Despite an abundance of articles in recent decades discussing LET in ACL reconstruction, no definitive indicators for extra-articular tenodesis have been described in the literature.

PURPOSE

Given the scarcity of literature assessing the indications in LET, the purpose of this study was to conduct a systematic review of the described indications for this operation in the context of concurrent ACL reconstruction.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

We searched PubMed, Cochrane Central, ScienceDirect, Web of Science, and Embase using the following key terms with no limits regarding the year of publication: (extraarticular OR extraarticular) AND (tenodesis OR plasty OR augmentation OR procedure or reconstruction OR reconstructive OR surgical OR surgery OR technique) AND (ACL OR anterior cruciate ligament). We included clinical human studies based on levels of evidence 1 to 4 that were written in English. We excluded studies not written in English, case studies, reviews, letters to editors, conference abstracts, or studies containing incomplete or irrelevant data.

RESULTS

The analysis evaluated 29 articles published between 1999 and 2023. We evaluated mostly level 3 (n = 13) and level 4 (n = 12) evidence; however, there were 4 articles with level 1 evidence. The majority of the studies were retrospective (n = 21), although there were prospective studies (n = 8). The mean age of the participants was 24.4 years. The most prevalent indications for LET were high-risk sports (16 articles), medial meniscal repair/excision (11 articles), and pivot-shift test grades 2 and 3 (11 articles).

CONCLUSION

The reviewed articles showed reduced pivoting and laxity, improved clinical outcomes, and decreased revision rates after primary ACL reconstruction. The main frequent and repeated indications for using LET in ACL reconstruction are meniscal surgery, sports activity, and grade 2 and 3 pivoting.

The Knee Anterolateral Ligament is Present in 82% of North Americans and 65% of Europeans but Only in 46% of Asian Studies: A Systematic Review of Frequency and Anatomy

PURPOSE

To perform an updated systematic review on the prevalence and morphological characteristics of the anterolateral ligament (ALL) in human cadaveric specimens.

METHODS

Medline, Embase, Scopus, and Google Scholar were searched for studies from 2012 to 2024 describing morphology. Study quality was assessed using the Critical Appraisal Skills Programme checklist and Quality Appraisal for Cadaveric Studies scale. Heterogeneity was analyzed with the I2 statistic, funnel plot, and Q-test. Mean effect size and 95% prediction intervals were calculated. Prevalence and anatomical measurements (length, width, thickness) were analyzed using mean and standard deviations.

RESULTS

Thirty studies were included. The Critical Appraisal Skills Programme identified 3 low-quality studies. Twelve studies met the Quality Appraisal for Cadaveric Studies quality threshold. The prevalence of the ALL was 61.7% (82% in North America, 64.9% in Europe, and 45.8% in Asia). The femoral insertion showed variability near the lateral femoral epicondyle and lateral collateral ligament, while the tibial insertion was midway between Gerdy's tubercle and fibular head. Histological analysis revealed 60% of studies identified ligamentous tissue similar to the anterior cruciate ligament. The mean ALL length was 39.7 mm, width 5.5 mm, and thickness 1.5 mm, with no significant morphological differences among populations.

CONCLUSIONS

This systematic review reveals that the ALL is present in 61.7%, with prevalence rates of 82% in North American studies, 65% in European studies, and 46% in Asian studies. The femoral insertion exhibited substantial variability at/around the lateral femoral epicondyle and lateral collateral ligament, lacking consistency. The tibial insertion was more consistently described as being located about halfway between Gerdy's tubercle and the fibular head. Histological analysis showed that 60% of the included studies identified the ALL as containing ligament-like or ligamentous tissue. The mean length of the ALL was 39.9 mm (range 31-59 mm), the mean width was 5.7 mm (range 2.2-9.0 mm), and the mean thickness was 1.5 mm (range 1.3-2.7 mm). No significant ethnic population differences were observed in morphological measures.

CLINICAL RELEVANCE

The ALL is not consistently present in all patients with knee instability, and the indications for performing an ALL reconstruction or lateral tenodesis remain unclear based solely on morphological factors. As a result, the decision to perform these procedures may need to be made on an individualized basis.

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.

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.

High Prevalence of Persistent Measurable Postoperative Knee Joint Laxity in Patients with Tibial Plateau Fractures Treated by Open Reduction and Internal Fixation (ORIF)

The development of post-traumatic osteoarthrosis after tibial plateau fracture (TPF) is multifactorial and can only be partially influenced by surgical treatment. There is no standardized method for assessing pre- and postoperative knee joint laxity. Data on the incidence of postoperative laxity after TPF are limited. The purpose of this study was to quantify postoperative laxity of the knee joint after TPF. Fifty-four patients (mean age 51 ± 11.9 years) were included in this study. There was a significant increase in anterior-posterior translation in 78.0% and internal rotation in 78.9% in the injured knee when compared to the healthy knee. Simple fractures showed no significant difference in laxity compared to complex fractures. When preoperative ligament damage and/or meniscal lesions were present and surgically treated by refixation and/or bracing, patients showed higher instability when compared to patients without preoperative ligament and/or meniscal damage. Patients with surgically treated TPF demonstrate measurable knee joint laxity at a minimum of 1 year postoperatively. Fracture types have no influence on postoperative laxity. This emphasizes the importance of recognizing TPF as a multifaceted injury involving both complex fractures and damage to multiple ligaments and soft tissue structures, which may require further surgical intervention after osteosynthesis.

The Role of Lateral Extra-articular Tenodesis in Anterior Cruciate Ligament Reconstruction and Treatment of Rotatory Knee Instability: a Scoping Review

PURPOSE OF REVIEW

The addition of lateral extra-articular tenodesis (LET) to anterior cruciate ligament (ACL) reconstruction (ACLR) has become increasingly popular to address residual rotatory knee instability. The purpose of this article is to review the anatomy and biomechanics of the anterolateral complex (ALC) of the knee, outline different LET techniques, and provide biomechanical and clinical evidence for its use as an augmentation procedure with ACLR.

RECENT FINDINGS

Rotatory knee instability has been identified as a common contributor to ACL rupture in both the primary and revision settings. Several biomechanical studies have shown that LET reduces strain on the ACL by decreasing excess tibial translation and rotation. Additionally, in vivo studies have demonstrated restoration of side-to-side differences in anterior-posterior knee translation, higher rates of return to play, and overall increased patient satisfaction following combined ACLR and LET. As a result, various LET techniques have been developed to help offload the ACL graft and lateral compartment of the knee. However, conclusions are limited by a lack of concrete indications and contraindications for use of LET in the clinical setting. Recent studies have shown that rotatory knee instability contributes to native ACL and ACL graft rupture and LET may provide further stability to reduce rates of failure. Further investigation is needed to establish concrete indications and contraindications to determine which patients would most benefit from added stability of the ALC.

Design and Optimization of Lower Limb Rehabilitation Exoskeleton with a Multiaxial Knee Joint

To facilitate rehabilitation training for patients, we proposed the implementation of an anthropomorphic exoskeleton structure that incorporates a variable instantaneous center of rotation (ICR). This design considers the variability in knee ICR among individuals, resulting from the irregular form of the human knee joint, and leverages a double-degrees-of-freedom (2DOF) five-bar mechanism to adapt to these differences. The walking gait of the human lower limb and the corresponding knee ICR were measured and calculated using an optical 3D motion capture system. The optimal dimension parameters of the five-bar mechanism were then obtained through the optimization of human movement position inputs and rod length constraints to minimize the error in knee ICR, gait angle, and ankle trajectory between the human and the exoskeleton. Finally, we established an exoskeleton prototype to conduct relevant experimental tests. The experiment results showed that the average errors of knee ICR trajectory, hip angle, knee angle, and ankle trajectory were 5.52 × 10-4 m, 0.010 rad, 0.014 rad, and 1.57 × 10-3 m, respectively. The experimental results demonstrated that the exoskeleton's movement trajectory was close to the human's, reducing the human-mechanism interaction force and improving patient comfort during rehabilitation training.

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.

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.

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

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

Recent advances on transdermal delivery systems for the treatment of arthritic injuries: From classical treatment to nanomedicines

Arthritic injuries happen frequently during a lifetime due to accidents, sports, aging, diseases, etc. Such injuries can be cartilage/bone injuries, tendon injuries, ligament injuries, inflammation, pain, and/or synovitis. Oral and injective administration of therapeutics are typically used but cause many side effects. Transdermal administration is an alternative route for safe and efficient delivery. Transdermal formulations of non-steroidal anti-inflammatory drugs have been available on market for years and show promising efficacy in pain relieving, inflammation alleviation, infection control, and so on. Innovative transdermal patches, gels/films, and microneedles have also been widely explored as formulations to deliver therapeutics to combat arthritic injuries. However, transdermal formulations that halt disease progression and promote damage repair are translated slowly from lab bench to clinical applications. One major reason is that the skin barrier and synovial capsule barrier limit the efficacy of transdermal delivery. Recently, many nanocarriers, such as nanoparticles, nanolipids, nanoemulsions, nanocrystals, exosomes, etc., have been incorporated into transdermal formulations to advance drug delivery. The combined transdermal formulations show promising safety and efficacy. Therefore, this review will focus on stating the current development of nanomedicine-based transdermal formulations for the treatment of arthritic injuries. The advances, limitations, and future perspectives in this field will also be provided to inspire future studies and accelerate clinical translational studies. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Biology-Inspired Nanomaterials > Lipid-Based Structures.

Synergistic effect of the anterolateral ligament and capsule injuries on the knee laxity in anterior cruciate ligament injured knees: A cadaveric study

INTRODUCTION

There is much controversy about the practical role of the anterolateral ligament (ALL) and its relation to other anterolateral knee structures including the anterolateral capsule (ALC) and iliotibial band (ITB). The purpose of this cadaveric study was to investigate the effect of the ALL and ALC injuries on knee laxity with the iliotibial band (ITB) preserved in the anterior cruciate ligament (ACL)-injured knee.

HYPOTHESIS

The ALL and ALC would contribute to knee joint stability during anterior translation and internal rotation of the tibia in an ACL-injured knee.

MATERIAL AND METHODS

For 10 fresh-frozen cadaveric knees, we measured knee laxity with the following state of knee injuries with ITB preserved: (1) intact knee, (2) ACL-sectioned knee (ACL-), (3) additional sectioning of the ALL (ACL-/ALL-), and (4) additional sectioning of the ALC (ACL-/ALL-/ALC-). We did biomechanical measurements in 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 we sectioned the ALL (ACL-/ALL-), the mean IR at 0°, 30°, 60°, and 90° of knee flexion were significantly increased, compared to the intact knee (p=<0.001, <0.001, <0.001, and 0.002) and ACL- (p=<0.001, <0.001, <0.001, and 0.002). The additional transection of the ALC (ACL-/ALL-/ALC-) significantly increased IR laxity from the ACL-/ALL- at 30°, 60°, and 90° (p=0.005, 0.003, and 0.047). For anterior laxity, ACL-/ALL- resulted in significantly increased anterior laxity from the ACL- at 30° and 60° (p=0.003 and 0.019), and ACL-/ALL-/ALC- significantly increased anterior laxity even from the ACL-/ALL- at 30° and 60° (p=0.007 and 0.011). For varus laxity, ACL-/ALL- resulted in significantly increased varus laxity from both the intact knee and ACL- at 60° (p=0.004 and 0.007) and 90° (p=<0.001 and<0.001). ACL-/ALL-/ALC- resulted in significantly increased varus from ACL-/ALL- at 60° and 90° (p=<0.001 and 0.003).

CONCLUSION

The anterolateral ligament and anterolateral capsule injuries in ACL-injured knees even with ITB preserved had a synergistic effect on knee laxity in the aspects of internal rotation, anterior translation, and varus angulation.

LEVEL OF EVIDENCE

II, Controlled laboratory study.

A proposal for a new morphological classification of the popliteus muscle tendon with potential clinical and biomechanical significance

The purpose of this study was to characterize the morphological variations in the proximal attachments and create an accurate classification of the PPM for use in planning surgical procedures in this area, for evaluating radiological imaging and rehabilitation. One hundred and thirty-four lower limbs of body donors (52 woman and 82 man) fixed in 10% formalin solution were examined. The popliteus muscle was present in all 134 limbs. Four main types were identified with subtypes. The most common type was Type I (34.3%), characterized by a single tendon in the popliteus sulcus. Type II (30.6%) characterized by a main tendon in the popliteus sulcus and accessory bands. This type was divided into five subtypes (A-E) based on presence of specific accessory bands. Type III (15.3%) was characterized by two tendons in the popliteal sulcus. Type IV (19.4%) was characterized by two tendons in the popliteus sulcus and additional bands. This type was also divided into five subtypes (A-E) based on presence of specific accessory bands. The popliteofibular ligament was present in 90.3% of cases. A new classification based on a proximal attachment is proposed. The popliteus tendon is characterized by a very high morphological variability, which can affect posterolateral knee stability and the natural rotation of the tibia. Such a classification system may be useful for clinicians performing medical procedures within the knee joint, including orthopedic surgeons.

Effects of Anterolateral Structure Augmentation on the In Vivo Kinematics of Anterior Cruciate Ligament-Reconstructed Knees

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction (ACLR) is a well-known treatment that restores the stability of ACL-deficient knees. However, some isolated ACL-reconstructed knees ultimately show rotatory laxity and develop osteoarthritis. Whether combined ACLR with anterolateral structure (ALS) augmentation (ALSA) can provide better improvement in the in vivo knee rotational kinematics remains unknown.

HYPOTHESIS

When compared with isolated double-bundle ACLR, combined double-bundle ACLR with ALSA can improve knee in vivo rotational kinematics and provide better restoration of knee kinematics.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixteen patients with unilateral ACL injury were randomly divided into 2 groups to receive either combined double-bundle ACLR and ALSA (ALSA group) or isolated double-bundle ACLR (ACLR group). All patients performed a single-leg lunge using the operative and nonoperative/contralateral legs under dual-fluoroscopic imaging system surveillance during a hospital visit at a minimum 1 year (12-13 months) of follow-up to assess the 6 degrees of freedom knee kinematics. Functional evaluation using the Lysholm and Marx rating scales and clinical examinations were also performed.

RESULTS

From full extension to approximately 90° of knee flexion at 5° intervals, the mean ± SD internal rotation of the reconstructed knees in the ALSA group (1.5°± 0.9°) was significantly smaller than that of the contralateral knees (8.2°± 1.9°; P = .008). The ALSA group knees also showed significantly (P = .045) more medial translation than the contralateral knees. In the ACLR group, the mean internal rotation of the reconstructed knee (6.0°± 2.1°) was significantly smaller than that of the contralateral knees (8.9°± 0.6°; P < .001). At full extension, the tibia was significantly more externally rotated than that of the contralateral legs (0.5°± 7.4° vs 7.6°± 3.4°, P = .049).

CONCLUSION

When compared with isolated double-bundle ACLR, double-bundle ACLR augmented with ALS reconstruction resulted in anterolateral rotatory overconstraint during the lunge motion.

CLINICAL RELEVANCE

Additional ALSA of double-bundle ACL-reconstructed knees overconstrained rotatory stability. Therefore, the use of ALSA for ACL-reconstructed knees should be considered with caution for patients with ACL deficiency and anterolateral rotatory instability. Longer-term follow-up to evaluate long-term outcomes and altered kinematics over time is recommended.

Impact of plantaris ligamentous tendon

There are countless morphological variations among the muscles, tendons, ligaments, arteries, veins and nerves of the human body, many of which remain undescribed. Anatomical structures are also subject to evolution, many disappearing and others continually emerging. The main goal of this pilot study was to describe a previously undetected anatomical structure, the plantaris ligamentous tendon, and to determine its frequency and histology. Twenty-two lower limbs from 11 adult cadavers (11 left, and 11 right) fixed in 10% formalin were examined. The mean age of the cadavers at death was 60.1 years (range 38–85). The group comprised six women and five men from a Central European population. All anatomical dissections of the leg and foot area accorded with the pre-established protocol. Among the 22 lower limbs, the PLT was present in 16 (72.7%) and absent in six (27.3%). It originated as a strong fan-shaped ligamentous tendon from the superior part of the plantaris muscle, the posterior surface of the femur and the lateral aspect of the knee joint capsule. It inserted to the ilio-tibial band. Histologically, a tendon and ligament were observed extending parallel to each other. A new anatomical structure has been found, for which the name plantaris ligamentous tendon is proposed. It occurs around the popliteal region between the plantaris muscle, the posterior surface of the femur, and the ilio-tibial band.

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.

The anterolateral ligament of the knee is not a solid structure in human fetuses

PURPOSE

The purpose of this study was to investigate if the anterolateral ligament of the knee (ALL) is present in the human fetus and describe its topography along with other structures of the region.

METHODS

Forty human fetuses knee joints, at mean age 34 weeks (± 2.57 weeks), fixed in 10% formalin, were submitted to cross-sectional dissection and mesoscopic analysis.

RESULTS

The ALL was not identified, although the usual topography of the region was identified in all specimens: skin, subcutaneous tissue, iliotibial tract (ITT), fibular collateral ligament, popliteal muscle tendon, lateral meniscus, patellar ligament, infrapatellar fat pad, lateral patellar retinaculum, knee joint capsule, lateral inferior genicular vessels, and the biceps femoris tendon. The ITT reveals anterior (n = 12) and lateral thickening (n = 17) in some specimens. This thickening was found in both knees of the same subject in 6/20 specimens.

CONCLUSION

The anterolateral ligament of the knee is not a congenital or solid structure. Our results suggest that the ALL may be a deep layer of the ITT or part of the knee joint capsule, or its identification is evaluator dependent.

Editorial Commentary: Another Take on the Anterolateral Ligament: High-Grade Are Worse Than Low-Grade Injuries, But the Categorization Is Problematic

The anatomy, function, and existence of the anterolateral ligament (ALL) is still hotly debated and a controversial topic. Currently both basic biomechanical and clinical studies are not providing sufficient and strong evidence to either support or refute that the ALL plays an important role for knee stability. One could argue that stability is provided by the anterolateral complex, including the iliotibial band, Kaplan fibers, and the anterolateral capsule, which may contain a structure called the ALL. Magnetic resonance imaging (MRI) is routinely performed in patients with anterior cruciate ligament (ACL) injury, but unfortunately ALL injuries cannot be reliably diagnosed in patients with concomitant ACL tears. When dividing ALL injuries into high and low grade using preoperative MRI and investigating clinical outcomes after double-bundle ACL reconstruction, patients with high-grade injuries have inferior outcomes and a significantly greater revision rates. However, the limitations of this research reduce the validity of these conclusions: high rate of loss to follow-up above accepted standard, unequal size of their study groups, fragility index of zero, the inaccuracy of diagnosing ALL injuries in the presence of ACL tears on MRI, and the dilemma with randomly classifying high- and low-grade ALL injury based on MRI.

Predictive Factors Associated with Anterolateral Ligament Injury in the Patients with Anterior Cruciate Ligament Tear

BACKGROUND

The earlier studies did not assess the associated factors of anterolateral ligament injury, comprehensively. We sought to evaluate the independent predictive factors of anterolateral ligament injury in the patients with anterior cruciate ligament tear. Ultrasound scan has an emerging role in the diagnosis of anterolateral ligament injury.

MATERIALS AND METHODS

We included 198 patients with anterior cruciate ligament tear in this study. All the patients underwent knee ultrasound scan to diagnose the anterolateral ligament injury. The potential predictive factors of anterolateral ligament injury were compared between the patients with anterolateral ligament injury and the patients with the intact anterolateral ligament.

RESULTS

In all the patients, the anterolateral ligament was seen in the tibial and femoral portions using the ultrasound scan. One hundred and ten patients (55.6%) had anterolateral ligament injury and the anterolateral ligament was intact in 88 patients (44.4%). The lateral collateral ligament injury was significantly associated with the anterolateral ligament injury (p < 0.001). In addition, the iliotibial band injury had a significant relationship with the anterolateral ligament injury (p = 0.001). An increased lateral tibial slope was significantly associated with the anterolateral ligament injury (p = 0.031). Furthermore, the bone contusion of the lateral femoral condyle had a significant relationship with the anterolateral ligament injury (p = 0.004).

CONCLUSION

The independent predictors of anterolateral ligament injury included the lateral collateral ligament injury, iliotibial band injury, bone contusion of the lateral femoral condyle, and an increased lateral tibial slope.