Background: The anterolateral ligament (ALL) is a true well-defined ligament in the knee first described in 1879 by Segond. After the work of Claes et al., several studies were conducted about biomechanics and its role in stability of the knee. The anatomical existence of the ALL has been studied by and various radiographic diagnostic modalities and in cadavers. It originates from lateral femoral epicondyle and is inserted between Gerdy’s tubercle and the fibular head. There has been controversy about the existence of ALL in pediatric patients. The aim of this work was to confirm the presence of ALL in pediatric patients by using MRI. Materials and Methods: We reviewed the knee MRI scans of 100 pediatric patients (ages between one and 12 yr) who had no knee injury or congenital deformity and had been evaluated by an expert radiologist. Results: The ALL was detected in 90% of the pediatric patients with the use of MRI. Conclusions: The main finding of this study was that ALL can be seen in pediatric patients using MRI. Despite numerous studies, additional research is needed to further define the role of the ALL in knee function. Level of Evidence: Level IV.

2. Downloadedfromhttp://journals.lww.com/c-orthopaedicpracticebyrmPZughc3fjoCtCwopXeCpwrDODu1qJ6K6KwBbNN8Enh3ioCbziEqMSA2lcR3xKaPZl1gIUM0RoOY4sD+HQ1MhVycqAFfLLuGMUCXFRFuBKO3GHKWMyYIA==on06/24/2020
Anterolateral ligament in pediatric knees:
A radiographic study
Adel Hegaze, MDa
, Khalid Khashoggi, MDb
, Abdulraof Alqrache, MDc
, Abdullah Ashour, MDa
and Hesham N. Mustafa, MDd
a
Orthopedic Department, Faculty of Medicine, King Abdulaziz University, Saudi Arabia
b
Radiology Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
c
Clinical Biochemistry Department, Faculty of Medicine – Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia
d
Anatomy Department, Faculty of Medicine, King Abdulaziz University, Saudi Arabia
ABSTRACT
Background:
The anterolateral ligament (ALL) is a true well-defined ligament in
the knee first described in 1879 by Segond. After the work of
Claes et al., several studies were conducted about biomechanics
and its role in stability of the knee. The anatomical existence of
the ALL has been studied by and various radiographic diagnostic
modalities and in cadavers. It originates from lateral femoral
epicondyle and is inserted between Gerdy’s tubercle and the
fibular head. There has been controversy about the existence of
ALL in pediatric patients. The aim of this work was to confirm the
presence of ALL in pediatric patients by using MRI.
Materials and Methods:
We reviewed the knee MRI scans of 100 pediatric patients
(ages between one and 12 yr) who had no knee injury or
congenital deformity and had been evaluated by an expert
radiologist.
Results:
The ALL was detected in 90% of the pediatric patients with the
use of MRI.
Conclusions:
The main finding of this study was that ALL can be seen in
pediatric patients using MRI. Despite numerous studies, addi-
tional research is needed to further define the role of the ALL in
knee function.
Level of Evidence:
Level IV.
Key Words
knee, anterolateral ligament, ALL, MRI, pediatric
INTRODUCTION
T
he anterolateral ligament (ALL) was first described in
1879 by Paul Segond, a French surgeon, as a fibrous
band.1
In the past the status of the ALL as a true
ligament has been questioned, but it was recognized as a true
ligament in adults in 20122,3
by the description of its origin and
insertion. In addition, some studies used different radiographic
modalities to describe the anatomy of the ALL. Recent articles
have reported the function and biomechanics of the ALL and its
role in knee stabilization and pivot shifting phenomena in
comparison to other knee stabilization structures.2–5
The ALL is a well-defined ligament. It originates from the
lateral femoral epicondyle, distal and anterior to the lateral
collateral ligament. It crosses the joint line in an oblique
manner, with firm attachments to the lateral meniscus
and inserts between Gerdy’s tubercle and the tip of the
fibular head.1,6
The ligament stabilizes and limits internal
rotation of the knee joint; therefore, it affects the pivot shift
mechanism.7–10
In literature, few studies report the ALL in pediatric patients,
and most of those were cadaver studies. Although some of
those studies succeeded in locating the ligament and describ-
ing its anatomy,11,12
others denied it.9,13
One study that
located it showed a 100% result of the ALL in 20 specimens
studied,11
and another found it in 64% of specimens studied.12
In this study, we aim to confirm the presence of ALL using
magnetic resonance imaging (MRI).
MATERIALS AND METHODS
Ethical Review and Study Design
This radiographic study has been carried out in accordance
with the Code of Ethics of the World Medical Association
(Declaration of Helsinki). Patients provided a signed in-
formed consent for the procedures. This study was approved
by the Unit of Biomedical Ethics Research Committee of our
institution with an approval number of 587-18.
Patient Selection
A radiology consultant reviewed 100 pediatric patients who
had an MRI of the knee without intravenous contrast. The
Financial Disclosures: The authors report no conflicts of
interest.
Correspondence to Hesham N. Mustafa, MD, Department of Anatomy,
Faculty of Medicine, King Abdulaziz University, PO Box 80205, Jeddah
21589, Saudi Arabia
Tel: +966 566 764 762; fax: +966 126 400000 (20123);
e-mail: hesham977@hotmail.com.
1941-7551 Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.
O R I G I N A L R E S E A R C H
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3. patients were between 1 and 12 yr of age (mean age, 8.6 yr;
range 10.7 yr), and had diagnoses other than severe knee
injury, infection, congenital anomalies, marked deformity, or
hemarthrosis. The ALL was followed at its anatomical course,
at the tibial attachment, the joint line, and the femoral
attachment. All patients were imaged on a 1.5-T Symphony
system (Siemens Medical Solutions, Erlangen, Germany), 3-T
Verio system (Siemens Medical Solutions, Erlangen, Ger-
many), or 3-T Skyra system (Siemens Medical Solutions,
Erlangen, Germany). All the examinations included a
minimum of the following sequences: axial proton density
(PD)-weighted fast spin-echo (FSE) or turbo SE (TSE)
sequence; coronal PD- and T2-weighted FSE or TSE sequen-
ces; and either sagittal conventional PD- and T2-weighted SE
and FSE or TSE T2-weighted sequences or sagittal PD- and
T2-weighted FSE or TSE sequences. Additional sequences
included T1-weighted and T1- or T2-weighted gradient-
recalled echo sequences. All FSE and TSE sequences were fat
suppressed.
The examinations were performed using a single 3D MRI
system (Magnetom Verio, Siemens Healthcare, Erlangen,
Germany). The imaging protocol consisted of standard
multiplanar 2D FSE acquisitions and a SPACE 3D FSE
acquisition (Siemens Medical Solutions, Erlangen, Germany).
The conventional sequences included a sagittal PD-weighted
FSE and T2-weighted acquisitions, coronal PD fat-saturation
sequence, and axial and coronal fat saturation T2-weighted
acquisitions. A sagittal T1-weighted acquisition was also
utilized.
RESULTS
The ALL was detected in 90 of 100 patients (90%). The
ligament was visible using the MRI axial view from the
femoral attachment (Figure 1) through the joint line
(Figure 2) all the way to the tibial attachment (Figure 3)
and in the coronal view indicated by arrows (Figure 4). The
anterior part of the ligament at the femoral attachment and
tibial attachment was a hypointense structure, which was
approximately midway between Gerdy’s tubercle and the tip
of the fibular head. The femoral attachment had significant
variation; however, it was seen approximately 10-mm distal
to the femoral epiphyseal line.
DISCUSSION
The ALL of the knee is a capsular structure that runs from the
lateral femoral epicondyle to the lateral tibial plateau.14
This
structure was initially described by Segond15
in 1879 as a
pearly fibrous thickening of the lateral knee capsule that
emerged from the iliotibial band (ITB). In recent years,
studies have been conducted to understand the anatomical
structure and biomechanical role of the anterolateral aspect
of the knee in adults.16,17
Several terms and structures related
to the ALL include the anterolateral capsule, capsulo-osseous
layer of the ITB, midthird lateral capsular ligament, anterior
band of the lateral collateral ligament, and anterior oblique
band.16,17
The term “anterolateral ligament” was coined by
Vieria et al.18
in 2012, and it appears to have become the
common term used in recent literature.17
FIGURE 1. Femoral attachment (arrow).
FIGURE 2. Joint line (arrow).
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4. The landmark study by Claes et al.1
in 2013 renewed
interest in the anterolateral anatomy of the knee. In recent
years, many studies proved the existence of the ALL in adults
and described its anatomy and the possibility to detect it
radiographically.2–4
A systematic review conducted by Van
der Watt et al.14
found that the ALL was a distinct entity
present in 96% of examined specimens, although prevalence
across individual studies varied considerably.
There is a significant debate about the ALL with regard to
its existence, anatomy, and role in knee stability. In addition,
it has been a source of controversy among the orthopaedic
community.19
Sabzevari et al.13
used anatomical investiga-
tion in 21 fetal knees and were unable to find the ALL. In
2016, Shea et al.9
used eight pediatric cadavers and identified
the ALL only in one specimen and in 2017, 14 pediatric
specimens were used and the ligament was identified in nine
of 14.12
Anatomic and histological studies have proven the
presence of the ALL. In 2016, Helito et al.11
located the ALL
in 20 fetal cadavers. In another study conducted by Parker
and Smith in 2016,20
the ALL was identified in 96.2% of the
knees studied. The authors found three articles published in
2017; the first article identified the ligament in all 40
cadaveric fetal knees studied,21
the second article identified
the ligament in all 26 knees studied,22
and the third article
conducted by Shea et al.12
identified it in nine of the 14
pediatric patients studied. In 2018, the ALL was reported in
29 out of 30 cadaveric knees and in eight out of 12 cadaveric
knees in two different articles.23,24
Nonetheless, the year 2018 marked the use of MRI in
locating the ALL in pediatric patients.23–25
Many studies
used radiographic imaging to identify ALL. Muramatsu
et al.26
used three-dimensional MRI and located the ALL in
100% of both noninjured knees (40 knees) and ACL-injured
knees (60 knees). In 2018, Helito25
used the MRI to identify
the ALL in around 70% of 363 knees of participants who
were 18 yr of age or younger. Liebensteiner et al.27
imaged
61 pediatric patients by using MRI and concluded that the
ALL was present in pediatrics and could be visualized by
MRI. A study published in 2019 visualized ALL injuries in 30
patients out of 34 with ACL injury using MRI.28
In 2015, a
study conducted by Caterine et al.6
identified the ALL in all
19 cadaveric knees studied using MRI, anatomical dissec-
tion, and histological analysis. Biomechanically, the ALL
plays a key role in the anterolateral rotatory laxity as
concluded by Park et al.29
In 2018, after reviewing several
articles about ALL, Zaffagnini et al.19
concluded that the ALL
does exist.
In this study, the authors included pediatric patients
between 1 and 12 yr old without knee injuries. We
located the ALL using MRI in 90% of the cases distributed
among all the patients. The results of this study were similar
to the results published by Van der Watt et al.14
that found
the ALL in 96% of an adult sample, which suggests that the
ALL may be absent in a small portion of individuals
from birth.
CONCLUSIONS
The main finding of this study is that anterolateral ligaments
(ALL) can be seen in pediatric patients using MRI. Despite
numerous studies, additional research is needed to further
define the role of the ALL in knee function.
FIGURE 4. Coronal proton density with saturation image (TR = 3180, TE =
33) in a 12-year old male patient showing the normal appearance of the
anterolateral ligament (arrows).
FIGURE 3. Tibial attachment (arrow).
392 | www.c-orthopaedicpractice.com Volume 31 Number 4 July/August 2020
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