| Introduction |
 Primary ligaments of ankle include (see below for details)
- medial
- Deltoid ligament
- Calcaneonavicular ligament (Spring Ligament)
- lateral
- Syndesmosis (includes AITFL, PITFL, TTFL, IOL, ITL)
- Anterior talofibular ligament (ATFL)
- Posterior talofibular ligament (PTFL)
- Calcaneal fibular ligament (CFL)
- Lateral talocalcaneal ligament (LTCL)
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| Syndesmosis |
- Function
- responsible for integrity of ankle mortise
- Anatomy
- Syndesmosis components
- Anterior-inferior tibiofibular ligament (AITFL)
- Posterior-inferior tibiofibular ligament (PITFL)
- Transverse tibiofibular ligament (TTFL)
- Interosseous ligament (IOL)
- Inferior transverse ligament (ITL)
- Bassett's ligment is an abnormal accessory AITFL which can be a cause of ankle impingement
- Physical Exam
- test to identify a syndesmosis injury include
- external rotation test
- squeeze test
- Imaging
- AP and mortise ankle radiographs
- used to evaluate the tibiofibular clear space and tibiofibular overlap
- tibiofibular clear space shoulde be < 5 mm
- tibiofibular overlap for AP view > 10 mm
- weight bearing mortise view is most accurate for diagnosis
- Clinical conditions
- high ankle sprain & syndesmosis injury
- ankle fracture
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| Anterior talofibular ligament (ATFL) |
- Function
- primary restaint to inversion in plantar flexion
- resistes anterolateral translation of talus in the mortise
- weakest of the lateral ligaments
- Anatomy
- extends from the anteriorinferior border of the fibula to the neck of the talus
- origin is 10mm proximal to tip of fibula
- inserts directly distal to articular cartilage of the talus (18mm distal to joint line)
- runs 45°-90° to longitudinal axis of the tibia
- Physical exam
- anterior drawer in 20° of plantar flexion
- test competency by anterior drawer in 20° of plantar flexion and compare to uninjured side
- forward shift of more than 8 mm on a lateral radiograph is considered diagnostic for an ATFL tear
- Imaging
- stress radiographs
- more accurate in chronic injuries
- MRI
- can diagnose injury
- arthroscopic findings
- can confirm MRI imaging
- ultrasound
- more accurate that radiographs
- Clinical Conditions
- low ankle sprains
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| Posterior Talofibular ligament (PTFL) |
- Function
- strongest of the lateral ligaments
- plays only a supplementary role in ankle stability when the lateral ligament complex is intact
- under greatest strain in ankle dorsiflexion and acts to limit posterior talar displacement
within the mortise as well as talar external rotation
- if ATFL and CFL are incompetent then
- short fibres of PTFL restrict internal and external rotation, talar tilt, and dorsiflexion;
- long fibres inhibit only external rotation, talar tilt, and dorsiflexion
- Anatomy
- origin is posterior border of fibula
- inserts on posterolateral tubercle of the talus
- runs perpendicular to longitudinal axis of the tibia
- Physical exam
- no specific clinical test for isolated PTFL injury
- Imaging
- MRI can indicate structural injury, rarely indicated
- Clinical Conditions
- rarely injured, except in association with a complete dislocation of the talus
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| Calcaneal Fibular Ligament (CFL) |
- Function
- primary restrain to inversion in neutral or dosrsiflexed postion
- restrains subtalar inversion, thereby limiting talar tilt within mortise
- Anatomy
- origin is anterior border of fibula, 9mm proximal to distal tip
- inserts on calcaneus 13mm distal to subtalar joint and deep to peroneal tendon sheaths
- Physical exam
- inversion (supination) test
- perform with ankle in slight dorsiflexion
- talar tilt test
- angle formed by tibial plafond & talar dome is measured as inversion force is applied to hindfoot (<5 deg is normal for most ankles)
- useful for evaluation of combined injury of both ATFL and CFL ligament
- Imaging
- talar tilt radiographs
- ankle arthrograms
- CFL rupture can lead to extra-articular dye leakage into the peroneal tendon sheath
- MRI
- Clinical Conditions
- injury occurs with ankle inversion with the foot in the neutral position
- low ankle sprain
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| Lateral talocalcaneal ligament (LTCL) |
- Function
- thought to stabilize the talocalcaneal joint
- Anatomy
- short narrow ligamentous band that connects the lateral process of the talus to the lateral surface of the calcaneus
- located anterior and medial to calcaneofibular ligament
- Physical Exam
- no specific test for this ligament
- Imaging
- LTCL ligament (red arrows) identified distinctly from the calcaneofibular ligament
- relationship of the calcaneofibular ligament (green arrow) and the LTCL (red arrow)
- Clinical conditions
- often injured in conjunction with ATFL injuries
- low ankle sprain
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| Deltoid ligament |
- Function
- Primary restraint to valgus tilting of the talus
- both the superficial and deep layers individually resist eversion of the hindfoot
- stabilizes ankle against plantar flexion, external rotation and pronation
- Anatomy
- superficial layer
- crosses both ankle and subtalar joints
- originates from anterior colliculus and fans out to insert into the navicular neck of the talus, sustenaculum tali, and posteromedial talar tubercle
- the tibiocalcaneal (sustenaculum tali) portion is the strongest component in the superficial layer and resists calcaneal eversion
- deep layer
- crosses only ankle joint
- functions as the primary stabilizer of the medial ankle
- prevents lateral displacement and external rotation of the talus
- originates from inferior & posterior aspects of medial malleolus and inserts on medial and posteromedial aspects of the talus
- Physical exam
- eversion test
- with ankle in neutral, evaluates superficial layer
- external rotation stress test evaluates syndesmosis and deep layer
- Imaging
- radiographs
- mortise radiograph with medial clear space widening can suggest injury
- gravity stress view can identify medial clear space widening
- MRI
- normal deltoid ligament
- ruptured deloitd ligament
- Clinical conditions
- anke fracture
- injury occurs with pronation (eversion) trauma leading to forced external rotation and abduction of ankle
- may occur with fracture of the medial malleolus
- high ankle sprain & syndesmosis injury
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| Calcaneonavicular Ligament (Spring Ligament) |
- Function
- static stabilizer of the medial longitudinal arch and head of the talus
- Anatomy
- attaches from the sustentaculum tali to the inferior aspect of the navicular
- Physical Exam
- flattening of medial longitudinal arch
- suspect injury in assoicated posterior tibial tendon pathology
- Imaging
- MRI
- can diagnose tear
- (green arrow, intact ligament; red arrow, disrupted ligament)
- Clinical conditions
- posterior tibial tendon dysfunction
- calcaneonavicular ligament is the most likely ligament to be attenuated in a patient with a type II flatfoot deformity secondary to posterior tibial tendon dysfunction
- acute spring ligament tear
- acute trauma can occur with forceful landing on flat foot
- the tibialis posterior tendon is usually normal
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