Why they are difficult
The talus has extensive articular cartilage coverage and a vulnerable blood supply. Displaced neck or body fractures can therefore produce avascular necrosis, post-traumatic arthritis and malunion.
Initial assessment
- inspect skin for tenting or threatened necrosis
- document neurovascular status
- identify open injury
- reduce dislocation or gross displacement urgently when skin or neurovascular structures are threatened
- immobilise after reduction
High-energy injuries may be associated with:
- open wounds
- skin tenting
- dislocation
- neurovascular compromise
- other hindfoot fractures
Urgent reduction of a dislocated talus protects skin and neurovascular structures.
Imaging
Radiographs define gross alignment. CT is essential for most displaced fractures because it demonstrates:
- neck versus body fracture
- comminution
- subtalar and tibiotalar involvement
- malrotation or varus
CT is usually required after initial radiographs to define:
- neck/body fracture geometry
- comminution
- joint congruity
- associated fractures
Blood supply
The talar body receives blood from branches of the posterior tibial, dorsalis pedis and perforating peroneal systems, with important vascular channels around the talar neck and sinus tarsi. Increasing displacement can disrupt these vessels.
The talar body receives important supply from branches including the artery of the tarsal canal and other anastomotic vessels. Displacement can disrupt these pathways.
The risk of AVN increases with severity of displacement and dislocation, but AVN is not inevitable in every displaced fracture.
Treatment principles
For displaced fractures:
- obtain adequate exposure without unnecessary soft-tissue stripping
- restore length, rotation and neck alignment
- avoid residual varus
- achieve stable fixation
Dual approaches are often used to visualise both sides of the neck and improve rotational control.
Avascular necrosis
Risk is related strongly to initial displacement and dislocation rather than simply to the number of hours before definitive fixation. Urgent reduction of a dislocated talus remains important for skin and soft-tissue reasons.
Complications
- avascular necrosis
- subtalar arthritis
- ankle arthritis
- malunion, particularly varus
- infection in open injuries
- stiffness
Avascular necrosis does not automatically require immediate salvage surgery; symptoms, collapse and joint degeneration determine later treatment.
- AVN
- subtalar arthritis
- ankle arthritis
- malunion
- non-union
- infection
- stiffness
Why talus fractures are important
The talus has:
- extensive articular coverage
- limited muscular attachment
- vulnerable blood supply
Displaced neck and body fractures therefore risk:
- avascular necrosis
- post-traumatic arthritis
- malunion
- stiffness
Treatment
Nondisplaced selected fractures may be managed non-operatively with close imaging.
Displaced fractures usually require reduction and fixation to restore:
- neck length
- rotation
- subtalar congruity
- ankle congruity
The timing of definitive fixation can respect swollen soft tissues once urgent reduction has been achieved.
Hawkin-type radiographic sign
Subchondral lucency in the talar dome during follow-up can indicate preserved vascularity, but absence of this sign does not prove AVN.
FRCS synthesis
In talar fractures, separate two time-critical issues:
- reduce threatened skin/joint urgently
- perform definitive reconstruction when soft tissues permit