Distal tibiofibular syndesmosis injury
Disclosures
- updated 19 Dec 2022:
Nothing to disclose
Updates to Article Attributes
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was changed:
Distal tibiofibular syndesmosis injuries are a relatively frequent ankle injury, although less common than a fracture or lateral ankle sprain. They are estimated to comprise ~10% (range 1-20%) of ankle injuries.
Epidemiology
Associations
- anterior talofibular ligament injury
- fracture / bone contusion
- talar dome osteochondral injury 2
Pathology
The mechanism of injury is uncertain but thought to be the combination of forceful foot external rotation with concomitant leg internal rotation 2. Injuries can occur to one or more of the structures that make up the distal syndesmosis1:
- anterior inferior tibiofibular ligament (AITFL)
- posterior inferior tibiofibular ligament (PITFL)
- transverse tibiofibular ligament
- interosseous membrane
Radiographic features
Plain radiograph
Distal syndesmotic injury can easily be inapparent and therefore missed on plain x-ray, especially if it is not accompanied by a nearby fracture or widening of the tibiofibular clear space 2,3. Numerous measurements have been proposed for indirectly demonstrating syndesmotic injury but these vary across studies with no formed consensus. Some studies have shown 3:
- tibiofibular clear space >5.3 mm (AP view) has a sensitivity of 82% and specificity of 75% for syndesmotic injuries ref
-
tibiofibular overlap
- <6 mm (AP view)
- <2.8 mm (mortise view) has a sensitivity of 36% and specificity of 87% for syndesmotic injuries
- medial clear space >4-5 mm (mortise view) is considered indicative of deltoid ligament rupture and an indirect sign of a syndesmotic injury
Ultrasound
Aside from being readily available, ultrasonography has the added benefit of being a real-time dynamic modality, allowing the operator to perform manoeuvres on the ankle during imaging. The contralateral, uninjured, ankle can be imaged for comparison.
It can demonstrate:
- anterior inferior tibiofibular ligament injury 3,5, associated clear tibiofibular space diastasis 7, and bulging joint capsule 5
- interosseous membrane injury 6
MRI
MRI has been shown to accurately detect injuries to the ligamentous structures of the distal tibiofibular syndesmosis 1-3. The anterior inferior tibiofibular ligament is the one most often involved in such injuries and the most convenient to identify. 2 Direct signs of a ligamentous tear include: 2,4
- ligament takes an abnormal course
- ligament assumes an irregular contour
- AITFL cannot be visualised
Indirect signs 4:
- tibiofibular joint space fluid
- prolapsed interspace fat
Signal characteristics
-
T2
- acute ligamentous injury: hyperintense signal in the ligament with surrounding oedema
- chronic injury: thickened or disrupted ligament without oedema
-
T1 C+
- acute injury: injured ligaments enhance intensely
Practical points
- injuries to the high ankle tend to occur in order
- in intermediate injuries without syndesmotic widening on non-weight bearing x-rays and MRI, stress weight-bearing imaging may be of benefit and if instability (dynamic widening) is demonstrated then surgery is typically indicated
Treatment and prognosis
Surgical management options include an ORIF with syndesmotic screw(s) or a cord device e.g. TightRope®.
-<p><strong>Distal tibiofibular syndesmosis injuries</strong> are a relatively frequent ankle injury, although less common than a <a href="/articles/ankle-fractures-1">fracture</a> or <a href="/articles/lateral-ankle-sprain">lateral ankle sprain</a>. They are estimated to comprise ~10% (range 1-20%) of ankle injuries. </p><h4>Epidemiology</h4><h5>Associations</h5><ul>-<li><a href="/articles/anterior-talofibular-ligament-injury">anterior talofibular ligament injury</a></li>-<li>-<a href="/articles/ankle-fractures-1">fracture</a> / bone contusion</li>-<li>talar dome osteochondral injury <sup>2</sup>-</li>-</ul><h4>Pathology</h4><p>The mechanism of injury is uncertain but thought to be the combination of forceful foot external rotation with concomitant leg internal rotation <sup>2</sup>. Injuries can occur to one or more of the structures that make up the distal syndesmosis<sup>1</sup>:</p><ul>-<li><a href="/articles/anterior-inferior-tibiofibular-ligament-aitfl">anterior inferior tibiofibular ligament (AITFL)</a></li>-<li><a href="/articles/posterior-inferior-tibiofibular-ligament">posterior inferior tibiofibular ligament (PITFL)</a></li>-<li><a href="/articles/transverse-tibiofibular-ligament">transverse tibiofibular ligament</a></li>-<li><a href="/articles/interosseous-membrane">interosseous membrane</a></li>-</ul><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Distal syndesmotic injury can easily be inapparent and therefore missed on plain x-ray, especially if it is not accompanied by a nearby fracture or widening of the tibiofibular clear space <sup>2,3</sup>. Numerous measurements have been proposed for indirectly demonstrating syndesmotic injury but these vary across studies with no formed consensus. Some studies have shown <sup>3</sup>:</p><ul>-<li>-<a href="/articles/tibiofibular-clear-space">tibiofibular clear space</a> >5.3 mm (AP view) has a sensitivity of 82% and specificity of 75% for syndesmotic injuries <sup>ref</sup>-</li>-<li>-<a href="/articles/tibiofibular-overlap">tibiofibular overlap</a> <ul>-<li><6 mm (AP view)</li>-<li><2.8 mm (mortise view) has a sensitivity of 36% and specificity of 87% for syndesmotic injuries</li>-</ul>-</li>-<li>-<a href="/articles/medial-clear-space">medial clear space</a> >4-5 mm (mortise view) is considered indicative of <a href="/articles/deltoid-ligament-injury">deltoid ligament rupture</a> and an indirect sign of a syndesmotic injury</li>-</ul><h5>Ultrasound</h5><p>Aside from being readily available, ultrasonography has the added benefit of being a real-time dynamic modality, allowing the operator to perform manoeuvres on the ankle during imaging. The contralateral, uninjured, ankle can be imaged for comparison.</p><p>It can demonstrate:</p><ul>-<li>-<a href="/articles/anterior-inferior-tibiofibular-ligament">anterior inferior tibiofibular ligament</a> injury <sup>3,5</sup>, associated clear tibiofibular space diastasis <sup>7</sup>, and bulging joint capsule <sup>5</sup>-</li>-<li>-<a href="/articles/interosseous-membrane">interosseous membrane</a> injury <sup>6</sup>-</li>-</ul><h5>MRI</h5><p>MRI has been shown to accurately detect injuries to the ligamentous structures of the distal tibiofibular syndesmosis <sup>1-3</sup>. The anterior inferior tibiofibular ligament is the one most often involved in such injuries and the most convenient to identify. <sup>2</sup> Direct signs of a ligamentous tear include: <sup>2,4</sup></p><ul>-<li>ligament takes an abnormal course</li>-<li>ligament assumes an irregular contour</li>-<li>AITFL cannot be visualised</li>-</ul><p>Indirect signs <sup>4</sup>:</p><ul>-<li>tibiofibular joint space fluid</li>-<li>prolapsed interspace fat</li>-</ul><h6>Signal characteristics</h6><ul>-<li>-<strong>T2</strong><ul>-<li>acute ligamentous injury: hyperintense signal in the ligament with surrounding oedema</li>-<li>chronic injury: thickened or disrupted ligament without oedema</li>-</ul>-</li>-<li>-<strong>T1 C+</strong><ul><li>-<strong></strong>acute injury: injured ligaments enhance intensely</li></ul>-</li>-</ul><h4>Practical points</h4><ul>-<li>injuries to the high ankle tend to occur in order<ul>-<li><a href="/articles/anterior-inferior-tibiofibular-ligament-aitfl">anterior inferior tibiofibular ligament (AITFL)</a></li>-<li>interosseous membrane</li>-<li><a href="/articles/posterior-inferior-tibiofibular-ligament-pitfl">posterior inferior tibiofibular ligament (PITFL)</a></li>-</ul>-</li>-<li>in intermediate injuries without syndesmotic widening on non-weight bearing x-rays and MRI, <a href="/articles/ankle-stress-view">stress weight-bearing imaging</a> may be of benefit and if instability (dynamic widening) is demonstrated then surgery is typically indicated</li>- +<p><strong>Distal tibiofibular syndesmosis injuries</strong> are a relatively frequent ankle injury, although less common than a <a href="/articles/ankle-fractures-1">fracture</a> or <a href="/articles/lateral-ankle-sprain">lateral ankle sprain</a>. They are estimated to comprise ~10% (range 1-20%) of ankle injuries. </p><h4>Epidemiology</h4><h5>Associations</h5><ul>
- +<li><a href="/articles/anterior-talofibular-ligament-injury">anterior talofibular ligament injury</a></li>
- +<li>
- +<a href="/articles/ankle-fractures-1">fracture</a> / bone contusion</li>
- +<li>talar dome osteochondral injury <sup>2</sup>
- +</li>
- +</ul><h4>Pathology</h4><p>The mechanism of injury is uncertain but thought to be the combination of forceful foot external rotation with concomitant leg internal rotation <sup>2</sup>. Injuries can occur to one or more of the structures that make up the distal syndesmosis<sup>1</sup>:</p><ul>
- +<li><a href="/articles/anterior-inferior-tibiofibular-ligament-aitfl">anterior inferior tibiofibular ligament (AITFL)</a></li>
- +<li><a href="/articles/posterior-inferior-tibiofibular-ligament">posterior inferior tibiofibular ligament (PITFL)</a></li>
- +<li><a href="/articles/transverse-tibiofibular-ligament">transverse tibiofibular ligament</a></li>
- +<li><a href="/articles/interosseous-membrane">interosseous membrane</a></li>
- +</ul><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Distal syndesmotic injury can easily be inapparent and therefore missed on plain x-ray, especially if it is not accompanied by a nearby fracture or widening of the tibiofibular clear space <sup>2,3</sup>. Numerous measurements have been proposed for indirectly demonstrating syndesmotic injury but these vary across studies with no formed consensus. Some studies have shown <sup>3</sup>:</p><ul>
- +<li>
- +<a href="/articles/tibiofibular-clear-space">tibiofibular clear space</a> >5.3 mm (AP view) has a sensitivity of 82% and specificity of 75% for syndesmotic injuries <sup>ref</sup>
- +</li>
- +<li>
- +<a href="/articles/tibiofibular-overlap">tibiofibular overlap</a> <ul>
- +<li><6 mm (AP view)</li>
- +<li><2.8 mm (mortise view) has a sensitivity of 36% and specificity of 87% for syndesmotic injuries</li>
- +</ul>
- +</li>
- +<li>
- +<a href="/articles/medial-clear-space">medial clear space</a> >4-5 mm (mortise view) is considered indicative of <a href="/articles/deltoid-ligament-injury">deltoid ligament rupture</a> and an indirect sign of a syndesmotic injury</li>
- +</ul><h5>Ultrasound</h5><p>Aside from being readily available, ultrasonography has the added benefit of being a real-time dynamic modality, allowing the operator to perform manoeuvres on the ankle during imaging. The contralateral, uninjured, ankle can be imaged for comparison.</p><p>It can demonstrate:</p><ul>
- +<li>
- +<a href="/articles/anterior-inferior-tibiofibular-ligament">anterior inferior tibiofibular ligament</a> injury <sup>3,5</sup>, associated clear tibiofibular space diastasis <sup>7</sup>, and bulging joint capsule <sup>5</sup>
- +</li>
- +<li>
- +<a href="/articles/interosseous-membrane">interosseous membrane</a> injury <sup>6</sup>
- +</li>
- +</ul><h5>MRI</h5><p>MRI has been shown to accurately detect injuries to the ligamentous structures of the distal tibiofibular syndesmosis <sup>1-3</sup>. The anterior inferior tibiofibular ligament is the one most often involved in such injuries and the most convenient to identify. <sup>2</sup> Direct signs of a ligamentous tear include: <sup>2,4</sup></p><ul>
- +<li>ligament takes an abnormal course</li>
- +<li>ligament assumes an irregular contour</li>
- +<li>AITFL cannot be visualised</li>
- +</ul><p>Indirect signs <sup>4</sup>:</p><ul>
- +<li>tibiofibular joint space fluid</li>
- +<li>prolapsed interspace fat</li>
- +</ul><h6>Signal characteristics</h6><ul>
- +<li>
- +<strong>T2</strong><ul>
- +<li>acute ligamentous injury: hyperintense signal in the ligament with surrounding oedema</li>
- +<li>chronic injury: thickened or disrupted ligament without oedema</li>
- +</ul>
- +</li>
- +<li>
- +<strong>T1 C+</strong><ul><li>
- +<strong></strong>acute injury: injured ligaments enhance intensely</li></ul>
- +</li>
- +</ul><h4>Practical points</h4><ul>
- +<li>injuries to the high ankle tend to occur in order<ul>
- +<li><a href="/articles/anterior-inferior-tibiofibular-ligament-aitfl">anterior inferior tibiofibular ligament (AITFL)</a></li>
- +<li>interosseous membrane</li>
- +<li><a href="/articles/posterior-inferior-tibiofibular-ligament-pitfl">posterior inferior tibiofibular ligament (PITFL)</a></li>
- +</ul>
- +</li>
- +<li>in intermediate injuries without syndesmotic widening on non-weight bearing x-rays and MRI, <a href="/articles/ankle-stress-view">stress weight-bearing imaging</a> may be of benefit and if instability (dynamic widening) is demonstrated then surgery is typically indicated</li>
Images Changes:
Image 9 X-ray (Oblique) ( create )
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