SUMMARY

• Talus fractures (other than neck) are rare fractures of the talus that comprise of talar body fractures, lateral process fractures, posterior process fractures, and talar head fractures.

• Diagnosis is made radiographically with foot radiographs but CT scan is often needed for full characterization of the fracture.

• Treatment is generally nonoperative with immobilization for minimally displaced injuries and surgical reduction and fixation for displaced and intra-articular fractures. 

EPIDEMIOLOGY

• Incidence

  • rare

    • less than 1% of all fractures

    • second most common tarsal fractures after calcaneus fxs

• Anatomic location

  • talar body fractures

    • account for 13-23% of talus fractures

  • lateral process fractures

    • account for 10.4% of talus fractures

  • talar head fracture

    • least common talus fracture

ETIOLOGY

• Mechanism

  • talar body

    • injuries often result from high energy trauma, with the hindfoot either in supination or pronation

  • lateral process of talus

    • injuries result from forced dorsiflexion, axial loading, and eversion with external rotation

      • often seen in snowboarders

ANATOMY

• 3D Anatomy of talus 

• Talus has no muscular or tendinous attachments

• Articulation

  • there are 5 articulating surfaces

    • seventy percent of the talus is covered by cartilage

    • inferior surface articulates with posterior facet of calcaneus

  • talar head articulates with

    • navicular bone

    • sustenaculum tali

  • lateral process articulates with

    • posterior facet of calcaneus

    • lateral malleolus of fibula

      • this forms the lateral margin of the talofibular joint

  • posterior process consist of medial and lateral tubercle separated by groove for FHL

• Blood supply

  • because of limited soft tissue attachments, the talus has a direct extra-osseous blood supply

  • sources include 

    • posterior tibial artery

      • via artery of tarsal canal (most important and main supply)

        • supplies most of talar body

      • via calcaneal braches

        • supplies posterior talus

    • anterior tibial artery

      • supplies head and neck

    • perforating peroneal arteries via artery of tarsal sinus

      • supplies head and neck

    • deltoid artery (located in deep segment of deltoid ligament)

      • supplies body

      • may be only remaining blood supply with a talar neck fracture

CLASSIFICATION

• Anatomic classification

• Anatomic classification
  Lateral process fracture
  Type 1	Fractures do not involved the articular surface
  Type 2	Fractures involve the subtalar and talofibular joint
  Type 3	Fractures have comminution
  Posterior process
  Posteromedial tubercle	Avulsion of the posterior talotibial ligament or posterior deltoid ligament
  Posterolateral tubercle	Avulsion of the posterior talofibular ligament
  Talar head fracture
  Talar body fracture

PHYSICAL EXAM

• Symptoms

  • pain

    • lateral process fractures often misdiagnosed as ankle sprains

• Physical exam

  • provocative tests

    • pain aggravated by FHL flexion or extension may be found with a posterolateral tubercle fractures

IMAGING

• Radiographs

  • recommended views

    • AP and lateral

      • lateral process fractures may be viewed on AP radiographs

    • Canale View 

      • optimal view of talar neck

      • technique

        • maximum equinus

        • 15 degrees pronated

        • Xray 75 degrees cephalad from horizontal

    • careful not to mistake os trigonum (present in up to 50%) for fracture 

    • may be falsely negative in talar lateral process fx

• CT scan

  • indicated when suspicion is high and radiographs are negative 

     

    • best study for posterior process fx, lateral process fx, and posteromedial process fx

  • helpful to determine degree of displacement, comminution, and articular congruity

• MRI

  • can be used to confirm diagnosis when radiographs are negative

TREATMENT

• Nonoperative

  • SLC for 6 weeks

    • indications

      • nondisplaced (< 2mm) lateral process fractures

      • nondisplaced (< 2mm) posterior process fractures

      • nondisplaced (< 2mm) talar head fractures

      • nondisplaced (< 2mm) talar body fractures

    • technique

      • cast molded to support longitudinal arch

• Operative 

   

  • ORIF/Kirshner wire Fixation 

     

    • indications

      • displaced (> 2mm) lateral process fractures

      • displaced (> 2mm) talar head fractures

      • displaced (> 2mm) talar body fractures

        • medial, lateral or posterior malleolar osteotomies may be necessary

      • displaced (> 2mm) posteromedial process fractures

        • may require osteotomies of posterior or medial malleoli to adequately reduce the fragments

  • fragment excision

    • indications

      • comminuted lateral process fractures 

         

      • comminuted posterior process fractures

      • nonunions of posterior process fractures

TECHNIQUE

• ORIF/Kirshner Wires

  • approaches

    • lateral approach

      • for lateral process fractures

      • incision over tarsal sinus, reflect EDB distally

    • posteromedial approach

      • for medial tubercle of posterior process fracture or for entire posterior process fracture that has displaced medially

      • between FDL and neurovascular bundle

    • posterolateral approach

      • for lateral tubercle of posterior process fractures

      • between peroneal tendons and Achilles tendon (protect sural nerve)

      • beware when dissecting medial to FHL tendon (neurovascular bundle lies there)

    • combined lateral and medial approach

      • required for talar body fractures with more than 2 mm of displacement

• Fragment excisions

  • incompetence of the lateral talocalcaneal ligament is expected with excision of a 1 cm fragment

    • this is biomechanically tolerated and does not lead to ankle or subtalar joint instability 

       

COMPLICATIONS

• AVN

  • Hawkins sign (lucency) indicates revascularization 

    • lack of Hawkins sign with sclerosis is indicative of AVN 

• Talonavicular arthritis

  • posttraumatic arthritis is common in all of these fractures

  • this can be treated with an arthrodesis of the talonavicular joint

• Malunion

• Chronic pain from symptomatic nonunion

  • may have pain up to 2 years after treatment

• Subtalar arthritis 

   

  • found in 45% of patients with lateral process fractures, treated either non-operatively or operatively 

     

    • anatomic reduction of the articular surface can decrease incidence

PROGNOSIS

• Lateral process injuries have a favorable outcomes with prompt diagnosis and immediate treatment