The Analysis of Magnetic Resonance Imaging in the
Diagnosis of Ankle Syndesmotic Injury
Courtney Nestor
April 19th, 2013
ATH 314-10
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Context
When dealing with sports injuries, it is extremely important to be able to identify
the different deep anatomical structures that could be involved. One of the most common
injuries, if not the most common, is the “ankle sprain,” however, there are numerous
different possible ligaments that could be sprained. The most common type of ankle sprain
is that of the lateral ankle, which includes the anterior talofibular, posterior talofibular, and
calcaneofibular ligaments. The reason for the high incidence of lateral ankle sprains is the
specific mechanism of injury: a forceful inversion of the ankle, with possible internal
rotation.
Although the lateral sprains are the most common sport’s injury, the most
aggressive is the “high ankle sprain,” which is specific to the interosseous ligaments
between the tibia and the fibula. There are five total ligaments that belong to the
interosseous membrane, but the distal portion is the most commonly injured, with or
without fracture of the tibia and/or fibula (Miyamoto & Takao, 2011; pg. 14). The most
distal portion is made up of both the anterior and posterior inferior tibiofibular ligaments
(AITFL and PITFL, respectively) and is considered the “tibiofibular syndesmosis.” The
location and strength of these ligaments make injuries difficult to sustain and the true
mechanism of syndesmotic injury is unknown. However, the most common mechanism that
causes syndesmotic injury is external rotation with or without dorsiflexion of the ankle,
under full weight-bearing status. When there is an injury, it is usually more severe than the
common lateral ankle sprain and also takes longer to heal, comparatively.
Diagnosis of this specific ankle sprain has been greatly disputed. Mainly orthopedic
testing and radiography are used to diagnose, however arthroscopy is considered the
golden standard. Orthopedic testing can diagnose an injury using the lower leg compression
test, which is positive with pain, but cannot definitively show a sprained syndesmosis
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structure because it does not give access to actuality inside the leg, thus cannot be fully
effective. X-rays can show the tibia and fibula clearly, however the soft tissue is difficult to
see unless it has been pulled away from it’s insertion and avulsed from the bone. Magnetic
Resonance Imaging, MRI, is the diagnostic modality that can be used for definitively
diagnosing nearly any soft-tissue damage, and may be the new primary technique in
diagnosing a syndesmotic injury.
MR imaging is becoming increasingly popular for identifying hard and soft tissue
structures, such as bones and ligaments, respectively. It has been used to view the swelling
of the brain, impingement of the elbow and shoulder, and lastly ligamentous tears in the
lower leg. The latter has become better respected in recent times due to its ability to view
structures from many different angles and positions. Particularly for the ankle syndesmosis,
it is useful to have the ability to identify the connective tissue’s integrity as well as the
bone’s integrity due to the connection between syndesmosis injury and broken bone. The
two disorders usually go together due to the excessive forces placed on the structures. The
use of MRI will decrease the unknown variables (as in, broken bones and/or disrupted
ligamentous structures) and could prove to be increasingly useful as more research is done
on the syndesmosis and it’s pathologies.
Objective
The main objective of this paper is to decide how well MRI can visualize the
syndesmotic structures and if it can be predominantly used in diagnosing structure
disruption or injury. In people with acute or chronic injury to the tibiofibular ligaments, the
sensitivity, specificity, and accuracy of magnetic resonance imaging is discussed and proven
to accurately diagnose injury.
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Data Sources
Databases that were used to find articles that pertained to the acuity of magnetic
resonance imagery in the ankle syndesmosis included PEDro, CINAHL, PubMed, ProQuest
Medical Library, EBSCOhost, and SPORTDiscus. The goal time frame for included studies
was from twenty-five years ago to the present year, meaning studies that were researched
and/or published in or after 1987. Key terms that directly correlated to the objective were
included within this analysis. These include syndesmotic ligaments (MR), ankle (MR), ankle
(injuries), tibiofibular syndesmosis, MRI (sensitivity and specificity), MR Imaging, ankle
(interosseous ligament/soft tissue), chronic syndesmosis, and Magnetic Resonance Imaging.
Words that pertained to structures that are commonly incorporated with the ankle
syndesmotic injury but do not exactly match the objective were excluded. These excluded
terms include the anterior and posterior talofibular ligaments, the calcaneofibular ligament,
and injuries to the “lateral ankle.”
Study Selection
Studies were selected carefully, using strong inclusive criteria. Criterion of the
studies included a recent timeframe, meaning researched and published within the last
twenty-five years, being written or translated properly in English, and being classified as a
scholarly article which has been previously peer-reviewed. Other inclusive criteria included
the type of study, including cohort-studies, case control studies, randomized controlled
trials, and meta-analyses.
Data Extraction
In total, four articles and studies were used to prove MRI’s diagnostic ability with
ankle syndesmosis injuries. The first of the investigations is “Tibiofibular Syndesmosis:
High-Resolution MRI Using a Local Gradient Coil,” by numerous health-care workers from
the Department of Radiology, Veterans Affairs Medical Center, and Department of Pathology
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from the University of California, San Diego, which discusses the ability of high-resolution
MRI to differentiate among the distal ankle ligamentous structures while in an intact
condition.
The second was “Injury of the Tibiofiular Syndesmosis: Value of MR Imaging for
Diagnosis,” by medical doctors Kazunori Oae, Masato Takao, Kohei Naito, Yuji Uchio,
Taisuke Kono, Jun Ishida, and Mitsuo Ochi, which directly compared MRI diagnostic
techniques with arthroscopy in determining injury. It also identified the sensitivity,
specificity, and accuracy of MRIs diagnostic ability. The third was “Chronic Tibiofibular
Syndesmosis Injury: The Diagnositc Efficiancy of Magnetic Resonance Imaging and
Comparative Analysis of Operative Treatment,” by Seung Hwan Han, Jin Woo Lee, Jin-Suck
Suh, and Yoon Rak Choi, which investigated the MRI technique and how well it worked to
diagnose injury, also using sensitivity, specificity, and accuracy. The last of the studies is
“Magnetic Resonance Imaging in the Diagnosis of Acute Injured Distal Tibiofibular
Syndesmosis,” by medical doctors T.J. Vogl, K. Hochmuth, T. Diebold, J. Lubrich, R. Hofman,
and U. St’Ockle, which talks about the potential of MRI to diagnose ankle syndesmosis injury
using mainly sensitivity and specificity.
Data Synthesis
Although “Tibiofibular Syndesmosis: High-Resolution MRI” did not look directly at
tibiofibular disruption, it perceived the general use of MRI on cadaveric bodies without
injuries to the syndesmotic ligaments. The examiners tested whether the intact structures
could be visualized with MRI because without that knowledge, disruptions would be
extremely difficult to identify due to the lack of information and ability to read negative
MRIs. In the axial plane of imaging, the AITFL was only seen in two of the eight cadaveric
specimens while the PITFL was seen in all eight of the bodies. In the coronal plane however,
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the AITFL was well visualized in the cadavers (Muhle, Frank, Rand, Ahn, Yeh, Trudell,
Haghighi & Resnick, 1998; pg. 940-9435).
In the last three sources, data was organized using arthroscopy as the standard of
reference. From these data sets, sensitivity and specificity were calculated. A “true-positive”
was considered the ratio between a positive finding using MRI and a positive finding using
arthroscopy and a “true-negative” was found as the ratio between a negative finding with
MRI and a negative finding using arthroscopy. A “false positive” was considered a positive
finding with MRI and a negative finding with arthroscopy and a “false negative” was a
negative finding with MRI while arthroscopic surgery identifies a positive finding.
Sensitivity is represented by the equation: number of true-positives/(number of truepositives + number of false-positives), while specificity is defined as the number of truenegatives/(number of true-negatives + number of false-negatives) (Oae, Takao, etc, 2003;
pg. 1576). Accuracy is denoted as the number of times an accurate reading is found by the
tested technique: MRI.
The results from Injury of the Tibiofibular Syndesmosis were extremely pertinent to
the objective and hypothesis. Of the 58 participants in the study, 28 were found positive for
syndesmotic “disruption.” Based on the criteria that discontinuous and/or curved
ligamentous structures were found “disrupted,” MR imaging correctly identified 28/28
AITFL disruptions and 5/5 PITFL disruptions (sensitivity equal to 1.0). Also based on the
same criteria, 28/30 AITFL and 53/53 PITFL were correctly determined negative, meaning
a specificity value of .93 and 1.0, respectively. The accuracy of the MRI testing was found to
be .97 for the AITFL disruptions and 1.0 for the PITFL disruptions (Oae, Takao, Naito, Uchio,
Kono, Ishida & Ochi, 2003; pg. 157-1586).
The second source, Chronic Tibiofibular Syndesmosis Injury, used a confidence
interval of 95%, meaning results were found statistically significant if the p-value was less
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than .05. The pre-operation MRI correctly identified disruption in 18 subjects and correctly
identified a lack of disruption in 55 subjects with chronic ankle instability and pain. There
were 3 false positives and 2 false negatives found, which yielded a sensitivity of .90 and a
specificity of .95 (Hwan Han, Woo Lee, Kim, Suh & Choi, 2007; pg. 3402).
Magnetic Resonance Imaging in the Diagnosis of Acute Injured Tibiofibular
Syndesmosis dealt with the acutely injured syndesmosis, and correctly found 36 of 38
disturbances. The sensitivity was .93 and the specificity was 1.0 for the injured syndesmosis
ligaments. The radiologists in the study preferred one type of MRI to another, however they
were both highly sensitive and specific and were concluded to be effective (Vogl, Hochmuth,
Diebold, Lubrich & Hofmann, 1997; pg. 404-4067).
Data Conclusion
Based on the studies that were discussed, there is evidence that magnetic resonance
imaging is an effective way to diagnose ankle syndesmotic disruption. Given the pending
severity of the injury, it is important that it is correctly identified in a timely manner as to
diminish any threat that there could be in the future.
The ability to locate and verify certain intact syndesmosis structures is crucial in
proving MRIs success. This is supported by the University of California’s Department of
Radiology, who proved that the distal syndesmotic structures could be effectively seen even
without obvious external disruption. It verifies that, when the ligaments are undamaged,
they can be found from various angles and equally differentiated from all positions.
Furthermore, according to Oae et al, Han et al, and Vogl et al there is a high
sensitivity and specificity involved with diagnostic MRI with respect to the ankle
syndesmosis complex. The overall high sensitivity implies that MRI has the capability to
successfully find a compensated syndesmosis ligament in acute and chronic situations. The
high specificity values indicate that there is the capability to successfully find a lack of
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injury, meaning that MRI can also definitively refute an orthopedic diagnosis of a
syndesmotic sprain. Though only one study, Oae et al, identified a value of accuracy, it
proved to be exemplary. A high accuracy value signifies a how well MRI actually tests
syndesmotic disruption. As research shows, MRI tests and shows not only uninvolved
tissue, but disrupted tissue as well.
Syndesmotic injuries are especially difficult to diagnose, treat, and rehabilitate; the
most complicated of the three being the diagnosis. Orthopedic testing leaves the examiner
and patient with many questions, such as which specific ligaments and/or structures are
involved and where and how severely are they disrupted. These questions and more can be
answered with the use of MR imaging.
The interosseous membrane, specifically the AITFL and the PITFL, is the tissue that
stabilizes and holds the tibia and fibula together. If it becomes weakened, torn, or sprained
the bones can begin to move excessively and cause chronic ankle pain and/or instability.
With aggressive diagnosis there is the possibility, with prompt, appropriate treatment and
rehabilitation, to not worry about future injury, but instead return to activity and normal
daily life without problems.
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References
1. Ebraheim, N., Taser, F., Shafiq, Q., & Yeasting, R. (2006). Anatomical evaluation and
clinical importance of the tibiofibular syndesmosis ligaments. doi:
10.1007/s00276-006-0077-0
2. Hwan Han, S., Woo Lee, J., Kim, S., Suh, J., & Choi, Y. (2007). Chronic tibiofibular
syndesmosis injury: the diagnostic efficiency of magnetic resonance imaging
and comparative analysis of operative treatment. Foot & Ankle International,
28(3), 336-342. doi: 10.3113/FAI.2007.0336
3. Milz, P., Milz, S. M., Steinborn, M., Mittlmeier, T., Putz, R., & Reiser, M. (1998). Lateral
ankle ligaments and tibiofibular syndesmosis. Acta Orthopaedica
Scandinavica, 69(1), 51-55.
4. Miyamoto, W., & Takao, M. (2011). Management of chronic disruption of the distal
tibiofibular syndesmosis. World Journal of Orthopedics, 2(1), 1-6.
5. Muhle, C., Frank, L. R., Rand, T., Ahn, J., Yeh, L., Trudell, D., Haghighi, P., & Resnick, D.
(1998). Tibiofibular syndesmosis: high-resolution mri using a local gradient
coil. Journal of Computer Assisted Tomography, 22(6), 938-944.
6. Oae, K., Takao, M., Naito, K., Uchio, Y., Kono, T., Ishida, J., & Ochi, M. (2003). Injury of
the tibiofibular syndesmosis: Value of mr imaging for diagnosis. Radiology,
227(1), 155-161.
7. Vogl, T., Hochmuth, K., Diebold, T., Lubrich, J., & Hofmann, R. (1997). Magnetic
resonance imaging in the diagnosis of acute injured distal tibiofibular
syndesmosis. (7 ed., Vol. 32, pp. 401-409). Lippincott-Raven Publishers.