Talar Fractures

Anatomy

  • 70% of the talus is covered with articular cartilage.
  • No muscular attachments or insertions.

Blood Supply

  • Three main vessels:
    • Posterior Tibial Artery (most important via artery of sinus canal).
    • Anterior Tibial Artery (dorsalis pedis).
    • Peroneal Artery (gives off sinus tarsi branch).
  • Anastomotic Sling:
    • Formed beneath the talar neck by sinus canal & sinus tarsi branches.
  • Regions supplied:
    • Dorsum: Anterior tibial (dorsalis pedis).
    • Head: Sinus tarsi (peroneal artery).
    • Body: Sinus canal (posterior tibial artery).
  • Intraosseous Anastomoses:
    • Medial wall supplied by a branch through the deltoid ligament.

Talar Neck Fractures

  • 50% of all talar fractures.
  • Mechanism:
    • Axial loading & forced dorsiflexion against the anterior tibia.
    • Neck is narrower with less dense bone, making it prone to fractures.
    • Supination often causes medial malleolar fracture.

Hawkins Classification (Rate of AVN)

  1. Type 1:
    • Undisplaced (<2mm).
    • AVN risk: 10-20%.
  2. Type 2:
    • Displaced with subtalar subluxation/dislocation.
    • AVN risk: 20-50%.
  3. Type 3:
    • Type 2 + Talotibial dislocation.
    • AVN risk: 50-90%.
  4. Type 4:
    • Type 3 + Talonavicular dislocation.
    • AVN risk: 100%.

Management

  • Type 1: Cast if undisplaced with angulation <5°.
  • Types 2-4: ORIF.

Surgical Approaches & Considerations

  • Approaches:
    • Combined anteromedial (medial to tibialis anterior) and anterolateral (lateral to EDL).
    • Posterolateral (between TA & FHL) for closed reduction with PA screws.
    • Medial malleolar osteotomy for increased exposure.
  • Screw Constructs:
    • Best construct: PA screws.
    • Crossed or AP screws also effective.
    • Sink screw heads to prevent impingement.
  • Comminution:
    • Plate medial side if there is medial wall comminution to prevent varus collapse.

Complications

  • Varus Malunion.
  • Avascular Necrosis (AVN):
    • Hawkins sign: Subchondral osteopenia at 8 weeks (indicates revascularization).
  • Post-Traumatic Arthritis.
  • Infection: High rate due to compound fractures.
  • Salvage Treatment:
    • Arthrodesis for affected joints.
    • Address varus deformity with medial column lengthening or lateral column shortening.

Talar Body Fractures

  • Less common than neck fractures.
  • High energy injuries, often associated with subtalar dislocation.
  • Treatment:
    • Similar to neck fractures.
    • Often intraarticular into the ankle joint.

Talar Process Fractures

  • Posterior, anterior, medial, or lateral processes.
  • Often mistaken for ankle sprains.
  • Non-operative Treatment:
    • Unless fragment is very large and non-comminuted.

Subtalar Dislocation

  • Mechanism:
    • High energy injury.
    • Inversion (medial) or eversion (lateral) dislocation.
    • Medial dislocation often associated with medial malleolus fracture.
  • Treatment:
    • Open reduction often required due to soft tissue interposition.
    • Medial dislocation: Peronei, EDB, EDC interposition.
    • Lateral dislocation: Tibialis posterior interposition.

Total Talar Dislocation

  • Devastating high-energy injury.
  • Often open fractures with 100% AVN and arthritis rates.
Back to top