Talar Neck / Body Fracture

 

Introduction

Location of injury is important for management and outcome:

  • Talar neck: 50%
  • Talar body: 25%
  • Talar process: 15%
  • Talar body: <10%

The lateral talar process is generally accepted as the dividing line between the talus neck and body.

The blood supply is relatively poor because:

  • 70% of the surface is covered in articular cartilage
  • No muscular attachments to provide local blood supply

The anatomy of the talus blood supply:

  • Deltoid branches of the posterior tibial artery supply most of the body
  • Dorsalis pedis and peroneal arteries supply the lateral third and neck.
  • As some vessels travel retrograde, talar neck fractures put the body at risk of AVN

 

Mechanism

  • High-energy injuries caused by forced dorsiflexion and axial loading of the foot
  • Rotational component implied by the presence of medial comminution and concurrent medial malleolar fracture (11-28%)
  • Associated other fractures in ~60%
  • ~ 20% are open fractures

 

Presentation

  • Pain, deformity, bruising, swelling
  • High energy mechanism – ATLS assessment and thorough 2y survey
  • Neurovascular status of the foot should be assessed
  • Skin tenting or skin threat
  • Open fractures may involve partial or complete talus extrusion

 

Imaging

  • Plain radiographs (AP, lateral and Canale views)
  • CT scan is the gold-standard
    • anatomy of the injury
    • fracture extension
    • comminution
    • articular congruency
    • occult fractures (e.g. Lisfranc, medial malleolus)

 

Hawkins classification

  • Based on displacement and dislocation
  • Further expanded by Canale and Kelly (1990), who added type IV
  • The risk of AVN (%) increases with classification grade

Hawkins

I

Undisplaced

0-13%

Hawkins

II

Subtalar dislocation

20-50%

Hawkins

III

Subtalar & tibiotalar dislocation

20-100%

Hawkins

IV

Pantalar dislocation

70-100%

 

Management

 

Undisplaced fracture

  • Non-weightbearing plaster cast for 6 weeks
  • Weekly early radiographs to ensure no fracture displacement
  • At 6 weeks, if signs of healing, convert to a walker boot with protected weight-bearing for an additional 6 weeks

 

Displaced fracture

Emergency Management

  • High energy = ATLS principles
  • In cases of skin threat or NV compromise:
    • emergency reduction
    • closed or open
    • temporary stabilisation (cast / k-wires / ex-fix)
  • If no immediate threat, recent literature suggests no difference in AVN rates with delay to reduction
    • can be done the next day with appropriate surgical expertise
    • when safe and with appropriate surgical expertise
    • temporary stabilisation as above until soft tissues settle
    • definitive fixation when safe and with appropriate expertise
  • Open fractures require emergent debridement and irrigation as per BOAST guidelines

 

Timing of definitive surgery

  • Recent literature suggests that immediate versus delayed ORIF has no significant difference in outcomes or rates of AVN

 

Surgical approaches

  • Avoid malreduction of the talar neck in supination, pronation, or axial malalignment.
  • Many authors recommend a dual anteromedial and anterolateral approach to obtain anatomical reduction
  • Medial malleolar osteotomy can be added as needed and avoids jeopardising the blood supply through a posteromedial approach
  • Single extended lateral approach has more recently been described

 

Anteromedial approach

  • Incision medial to the tibialis anterior tendon
  • Can extend for medial malleolus osteotomy, allowing better visualisation of body fractures and comminution
  • Avoid stripping the dorsal aspect of the neck and deltoid ligament attachment to preserve the remainder of the blood supply

 

Anterolateral approach

  • Incision lateral to the extensor digitorum longus (~1 cm above standard sinus tarsi approach)
  • Adequate skin bridge if dual approach used
  • Avoid injury to sinus tarsi vessels
  • If used in isolation:
    • extend incision up the distal fibula
    • divide retinaculum and ATFL ligament (often already torn)
    • allows excellent view of fracture
    • allows access to – and removal of – medial comminution
    • lateral fixation only
    • repair ATFL (modified Brostrum)

 

Arthroscopic assisted reduction

  • Theoretical advantages:
    • reduced exposure leading to minimal soft tissue damage
    • preservation of blood supply
    • improved visualisation of fracture fragments
    • accurate joint reduction control
  • Portals:
    • standard anteromedial and anterolateral ankle portals
    • sinus tarsi portal in cases involving interposed subtalar fragments
  • Principles:
    • K-wire inserted distal to the fracture on medial aspect of the talus head to aid in reduction (joystick)
    • reduction confirmed with fluoroscopy and arthroscopy
    • fixation performed, usually with two cannulated screws

 

Fixation techniques

Screws

  • Fractures can be fixed with screws used antegrade or retrograde
  • Minimum of 2 screws for stability
  • Biomechanical studies have suggested stronger fixation with posterior to anterior screw fixation, however accurate reduction is still imperative

Plates

  • For comminuted fractures, many authors have recommended plate fixation (solid buttress or bridging strut) +/-additional screw fixation
  • Can be applied to the most comminuted column: medial / lateral / both

 

Primary subtalar arthrodesis

  • Many patients with talar neck or body fractures may require subsequent interventions, including subtalar arthrodesis
  • Primary subtalar fusion may be an option in specific cases involving displaced and comminuted talar neck fractures where the progression to subtalar arthritis appears inevitable
  • The primary aims would be:
    • prevent progression to subtalar arthritis, pain and deformity
    • avoid multiple complex procedures
    • stabilise the foot by fixing the talus to an osseous strut

 

Postoperative management

  • Most surgeons prefer immobilisation in plaster cast for first 6 weeks
  • Observe for Hawkins’ sign:
    • prognostic indicator of revascularisation of the talar body
    • represents disuse osteopenia (can only occur if bone is vascularised)
    • appears between 6 and 8 weeks
    • visualised on the AP or mortise view
    • absence of Hawkins’ sign does not mean AVN!
  • Can progress to boot (for ankle exercises, hygiene, or night removal) but should remain non-weightbearing until there is evidence of healing, for up to 3 months

 

Outcomes

  • Functional outcomes vary inversely with increasing Hawkins grade
  • ~50% good/excellent outcomes after talar neck fracture
  • ~50% poor/fair
  • ~50% develop arthritis
    • body > neck fractures
    • subtalar > ankle OA

 

Complications

 

Avascular necrosis

  • Risks:
    • Greater displacement (Hawkins type)
    • tobacco use
    • open fractures
    • ipsilateral injuries
    • dual approaches
    • age
    • BMI
  • AVN rate is 30-40% overall
    • ~40% will revascularise
    • ~40% will collapse
  • Once AVN has been established, commence non- or partial weight-bearing to help prevent talar collapse
  • Surgical management of talar AVN includes:
    • drilling +/- bone grafting
    • vascularised bone grafting
    • adjacent joint fusion (subtalar / tibio-talo-calcaneal / pantalar) fusion
    • excision of talus and tibiocalcaneal fusion with femoral head allograft (including hindfoot nail / trabecular cages)
    • total talus replacement

 

Malunion and non-union

  • ~10% malunion with talar neck fractures (usually varus)
  • ~2.5% non-union
  • If malunion / non-union occurs with AVN / infection:
    • remove all necrotic / infected bone
    • hindfoot arthrodesis with bone grafting or shortening

 

 

References

  • Vallier HA, Nork SE, Barei DP, et al. Talar neck fractures: results and outcomes. J Bone Joint Surg Am 2004;86(8):1616–24.
  • Srinath A et al. Talar Neck Fractures With Associated Ipsilateral Foot and Ankle Fractures Have a Higher Risk of Avascular Necrosis. J Orthop Trauma. 2024 Jun 1;38(6):220-224.
  • Alley M, Vallier H, Tornetta P. Identifying Risk Factors for Osteonecrosis After Talar Fracture. J Orthop Trauma. 2024 Jan 1;38(1):25-30.
  • Jordan R et al. Complications of Talar Neck Fractures by Hawkins Classification: A Systematic Review. J Foot Ankle Surg. 2017 Jul-Aug;56(4):817-821.
  • Alton T, Patton D, Gee A. Classifications in Brief: The Hawkins Classification for Talus Fractures. Clin Orthop Relat Res. 2015 Sep; 473(9):3046–3049.
  • Dodd A, Lefaivre K. Outcomes of Talar Neck Fractures: A Systematic Review and Meta-analysis. J Orthop Trauma. 2015 May;29(5):210-5.
  • Vallier H et al. A new look at the Hawkins classification for talar neck fractures: which features of injury and treatment are predictive of osteonecrosis? J Bone Joint Surg Am. 2014 Feb 5;96(3):192-7.
  • Canale ST. Fractures of the neck of the talus. Orthopedics. 1990;13:1105–1115.
  • Hawkins L. Fractures of the neck of the talus. J Bone Joint Surg Am. 1970;52:991-1002.