Foot & Ankle International - June 2017 - 621

693207

FAIXXX10.1177/1071100717693207Foot & Ankle InternationalJung et al

research-article2017

Article

Magnetic Resonance Imaging and
Stress Radiography in Chronic Lateral
Ankle Instability

Foot & Ankle International®
2017, Vol. 38(6) 621-626
© The Author(s) 2017
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https://doi.org/10.1177/1071100717693207
DOI: 10.1177/1071100717693207
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Hong-Geun Jung, MD, PhD1, Na-Ra Kim, MD, PhD2, Tae-Hoon Kim, MD1,
Joon-Sang Eom, MD1, and Dong-Oh Lee, MD3

Abstract
Background: Studies regarding magnetic resonance imaging (MRI) findings of the lateral ankle ligaments in chronic lateral
ankle instability and their clinical relevance for surgery are lacking. This study classified the lateral ankle ligament MRI
findings of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) in chronic lateral ankle instability
(CLAI) and correlated these findings with ankle stress radiographs.
Methods: We included 132 ankles with CLAI that underwent ligament reconstructions from 2006 to 2013. The distributions
of the ATFL and CFL morphologies were evaluated using the following categories: (1) the amount of thickness: normal/
thickened/attenuated/non-visualized, (2) the presence of discontinuity, (3) wavy or irregular contour, and (4) increased
signal intensity on T2-weighted images. The relationships between the ligament morphologies and stress radiographs were
analyzed.
Results: The ATFL was normal in 5 (4%) ankles, thickened in 35 (27%), attenuated in 76 (58%), and non-visualized in 16
(12%), while the CFL was normal in 39 (30%) ankles, thickened in 42 (32%), attenuated in 44 (33%), and non-visualized in
7 (5%). Discontinuity of the ATFL or CFL was observed in 46 (35%) ankles. Wavy or irregular contours were observed
in 55 (42%) ATFLs and 37 (28%) CFLs, and signal intensity of both ligaments was increased in 19 (14%) ankles. ATFL (P <
.001) and CFL thickness (P = .007) correlated with the talar tilt angle.
Conclusions: The MRI findings of CLAI showed several morphologies and specific incidences for each morphology.
Attenuated, wavy appearance was the most frequent MRI pattern. Thickness was related to the degree of instability.
Level of Evidence: Level IV, retrospective case series.
Keywords: anterior talofibular ligament, calcaneofibular ligament, morphology, stress radiograph, talar tilt angle

Introduction
Lateral ankle sprains are among the most common injuries,6,9
and many patients are successfully treated with nonoperative
care. However, residual sequelae may produce chronic lateral
ankle instability (CLAI), which occurs in 20% to 40% of
acute ankle sprain patients.21 Because CLAI may be a major
cause of osteoarthritic changes and ankle pain,7,13,15,24 operative treatment may be required for CLAI patients who fail
nonoperative management.
Magnetic resonance imaging (MRI) facilitates the evaluation of the pathologic status of the lateral ankle ligaments and
other associated pathologic conditions in the ankle joint.5,19,23
Many surgeons may consider the MRI findings in the evaluation of the chronic morphologic state of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL)
when deciding among the operative options of ligament
reconstruction using the free tendon or direct ligament repair,
such as the modified Brostrom procedure. This approach is

adopted because direct ligament repair requires the presence
of substantial ligament tissues to achieve firm postoperative
ligament stability.3,8,10-12,14
However, few studies have focused on detailed MRI
findings of lateral ankle ligaments and their relationship
with CLAI mechanics despite the importance of understanding the morphologic characteristics of ligaments in
1

Department of Orthopedic Surgery, Konkuk University School of
Medicine, Gwangjin-gu, Seoul, Republic of Korea
2
Department of Radiology, Konkuk University School of Medicine,
Gwangjin-gu, Seoul, Republic of Korea
3
Department of Orthopedic Surgery, Myongji hospital, Gyeonggi-do,
Republic of Korea
Corresponding Author:
Dong-Oh Lee, MD, Department of Orthopedic Surgery, Myongji
hospital, 697-24 Hwajung-dong, Deokyang-gu Goyang-si, Gyeonggi-do,
412-270, Republic of Korea.
Email: ronaki@naver.com
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