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*very constrained joint( as a result of both it's bony anatomy and the ligamentous support

motion of the ankle

limited to one plane
*dorsi and plantar flexion*

ankle function

works in concert with the *subtalar* and
*transverse tarsal joints* (talonavicular and
calcaneocuboid joints) to provide the full
motions of the foot and to shock absorb with foot impact.

ankle complex

Key to Ankle Function and

mortise anatomy and robust ligamentous support

mortise function

Shape of the Joint and the Ligamentous Support


the result of Long Term Disruption of Either the Mortise Anatomy or the Ligamentous Stability

Bony Nomenclature of the Ankle

*medial malleolus* - medial shoulder of the distal tibia
*tibial plafond* - weight-bearing surface of the distal end of the tibia

posterior malleolus

-Not a precise anatomic structure
-refers to the curving posterior shoulder of the tibial plafond
-allows for better classification of ankle fractures


rectangular slot that accepts a tenon

achilles tendon

ligaments of the ankle

Lateral ligaments = ATFL, CFL, PTFL

deltoid ligament

*-Medial ligament*
-comprised of deep and superficial portions
-superficial deltoid inserts into the talus, calcaneous, in tarsal navicular bone
-superficial deltoid well-suited to resist hind foot eversion
-the deep deltoid ligament inserts in the central and posterior aspects of the medial talar surface
-resist external rotation, tilt, and lateral translation of the Talus

syndesmotic ligaments

factors that determine the characteristics of ankle injuries

Position of the Foot
Direction of Applied Force
Magnitude of Force
Patient Characteristics
-Bone Quality

ankle sprains

*Lateral Ligaments Most Commonly Injured*
Inversion Injuries
Syndesmotic Involvement = High Ankle
Degree of Damage = Grade

High Ankle Sprain

Syndesmotic Involvement

Most Commonly Injured ligament

lateral ligament

calcaneofibular ligament tear

results in abnormal inversion laxity talar tilt

lateral process talus fracture

ankle sprain impersonators

-OCLs of the talar dome
-ant process calcaneal fractures
-peroneal tendon dislocations
-lateral process talus fractures

peroneal tendon dislocation

achilles tendon rupture

-weekend warriors
-classic history
-physical findings

achilles tendon rupture diagnostic testing

*(+)ve Thompson test*

thompson test

tests Achilles tendon integrity

more common ankle fracture

malleolar fracture

more severe ankle fracture

pilon fracture

malleolar fracture type injury

Injury is
Torsion (Twisting)
and Bending

pilon fracture type injury

axial crush injury

Malleolar Fractures

-Medial Malleolar Fracture
-Lateral Malleolar Fracture (Fibula)
-Posterior Malleolar Fracture
-Bimalleolar Fracture: Medial and Lateral
Malleolar Fractures
-Trimalleolar Fracture: Medial, Lateral, and
Posterior Malleolar Fractures

The Goal of
All Ankle Fracture

Maintain or Restore the *Mortise Alignment* of the Ankle Joint

normal mortise view

look for joint space symmetry

treatment of Fibular Fractures with Intact Mortise


treatment of Medial Malleolar Fx with Intact Mortise


Mortise Disrupted: Lateral Malleolar
Fracture with Deltoid Ligament Tear


Ligaments of the ankle continued

Lateral malleolus

Distal end of the fibula that creates the lateral shoulder of the ankle joint
-has a strong ligamentous attachment to the distal tibia referred to as the syndesmosis of the ankle
-allows for limited rotational motion of the distal fibula relative to the tibia → results is increase in *ankle dorsiflexion*

tibial plafond

Weight-bearing surface of the distal end of the tibia

talar dome

-Weight-bearing surface of the talus
-mobile articular surface of the ankle joint
-wider anteriorly > posteriorly → need for fibula to rotate with dorsiflexion

3 main lateral ligaments of the ankle

-Anterior talofibular ligament (ATFL)
-calcaneofibular ligament (CFL)
-posterior talofibular ligament (PTFL)

Anterior talofibular ligament (ATFL)

-Primary *restraint to anterior displacement, internal rotation, and inversion of the talus*
-most commonly injured ligament of any joint

calcaneofibular ligament (CFL)

-Underneath the peroneal tendons
-most stressed under extremes of inversion
-*attaches distally onto calcaneus, contributing to subtalar joint stability*

posterior talofibular ligament (PTFL)

-*Strongest of the 3 main lateral ligaments*
-typically the last of the lateral ligaments to be injured, and only with severe injuries

superficial deltoid ligament

-inserts into the talus, calcaneous, in tarsal navicular bone

Superficial deltoid ligament function

-well-suited to *resist hind foot eversion*

deep deltoid ligament

-inserts in the central and posterior aspects of the medial talar surface

Deep deltoid ligament function

-resists* external rotation, tilt, and lateral translation of the Talus*

syndesmotic ligaments

-Consists of the anterior and *posterior inferior tibio-fibular ligaments, the interosseous ligament, and the inferior transverse ligament*
-allows for* rotational motions of the distal fibula in relationship to the distal tibia*
-as the ankle dorsiflexes, that fibula externally rotates to accommodate for the wider anterior portion of the talar dome

Factors determining the nature of ankle injuries

-Position of the foot
-direction of the applied force
-magnitude of the force

Factors determining the severity of ankle injuries

-Age, weight, and bone quality of the patient

Most common lower extremity injury

Ankle sprain

common ligament injured in sprains

Lateral ligaments

Most commonly injured ligament

Anterior talofibular ligament > CFL > PTFL

High ankle sprain

Involve the syndesmotic ligaments

Presentation of ankle injuries

-History of twist or fall
-audible pop possible
-difficulty preparing
-acute onset of swelling and bruising along the antero-lateral aspect of the ankle
-aching that increases with swelling

Determine the integrity of the ATFL

Anterior drawer test

stresses the CFL

Inversion testing/talar tilt

Symptoms of syndesmotic ligament involvement

Tenderness extending proximal to the ankle in the interval between the fibula and tibia
-*pain when squeezing the calf and compressing the fibula towards the tibia*

Management of ankle sprains

Bracing and crutches
Progressive weight bearing and functional rehabilitation

therapies that may help to optimize sprain recovery

-soft tissue massage
-graduated exercises to restore motion, strength, balance training proprioception

ankle sprain impersonators

-Achilles tendon rupture
-ankle fractures
lateral malleolus fracture
medial malleolus fracture
posterior malleolus fracture

Achilles tendon rupture epidemiology

-Most occur during athletic activity
-most commonly in males between the ages of 30 and 40 years old

Achilles tendon rupture history

-often diagnostic → patients often describe been feeling as if they have been kicked in the back of the calf

Achilles tendon rupture diagnosis

*Based on history and exam findings*
-asymmetrical April resting position
-palpable Achilles tendon defect and tenderness
-positive/abnormal Thompson test
-decreased plantar flexion strength

positive Thompson test

Decreased or absent passive ankle plantar flexion with posterior calf muscles squeeze compared to the normal side

When MRI is required to make the diagnosis of Achilles tendon rupture

-If the presentation is delayed and the patient is diffusely swollen

Management of Achilles tendon ruptures

-Advocates of both non-operative and operative treatment
-decision based on individual variables
-generally operative treatment → patients with high activity demands
-nonoperative treatment → elderly, less active individuals, and those with significant medical comorbidities
-both treatment modalities require lengthy rehabilitation

pilon fracture

-High energy crushing injury
-often result from MVAs or falls from a significant height
-almost always require surgical management
-high rate of long-term disability

malleolar fracture

-Twisting or bending forces to the ankle, similar to sprains
- more common than pilon fractures

Key to managing ankle fractures

Determining the stability of the mortise alignment
-if alignment is not significantly altered, injury can be treated non-surgically with good results
-if mortise is disrupted, surgical management is almost always required

Radiographic view required for evaluation of the ankle

AP, lateral, and mortise

mortise view radiograph

-Ankle is positioned with 15-20° of internal rotation
-exposes all of the joint spaces
-if it of the medial, lateral, and superior joint bases are not symmetrical indicates disrupted mortise

lateral malleolar fracture

*Distill fibular fracture*
-most common isolated ankle fractures
-if there's associated disruption of the deltoid ligament, the talus shifts laterally and the mortise is disrupted requiring surgical reduction

Location of lateral malleolar fractures that are generally associated with syndesmotic ligament tears

Fractures that are proximal to the syndesmosis with either a tear in the deltoid ligament or a medial malleolus fracture

Medial malleolar fractures

-uncommon isolated injuries
-most can be treated non-operatively

Posterior malleolar fractures

-Uncommon isolated injuries
-usually an element of a more complex injury

bimalleolar fracture

*Medial and lateral malleolar* fracture
-typically disrupts the mortise
-usually treated with open reduction and internal fixation

trimalleolar fracture

*Medial, lateral, and posterior malleolar* fractures
-most severe injury
-often associated with dislocation of the ankle and significant joint damage
-always treated with open reduction and internal fixation

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