FRACTURES OF THE TALUS
- Talus also known as ‘Astragalus’.
- Unique bone, has no muscle or tendon attachments.
- Held in place mainly by bony and ligamentous support.
- Posterior tibial artery—through calcaneal branches
- Anterior tibial artery—through anterolateral/ anteromedial malleolar branches or through medial tarsal artery
- Peroneal artery—through perforating branches
- Artery of the tarsal canal, a branch of posterior tibial artery
- Artery of the sinus tarsi, a branch of dorsalis pedis artery
- Fracture of the neck of the talus results from forced dorsiflexion of the ankle.
Classification of the Fractures/Dislocations and Fracture—Dislocations of the Talus
- Following injuries are seen in the talus:
- Talar neck fracture
- Talar body fracture
- Talar head fracture (rare)
- Subtalar dislocation
- Total talar dislocation
Classification of talar neck fracture
- Based on Hawkins’ classification (1970) it is classified as follows:
- Undisplaced vertical fracture.
- Displaced fracture with subtalar joint subluxation/ dislocation.
- Displaced fracture with both subtalar and ankle dislocation.
- Displaced fracture with subtalar, ankle and talonavicular dislocation.
- Based on Sneppen classification (1977) they are classified as follows:
- Osteochondral dome fractures
- Coronal, sagittal, horizontal shear fractures
- Posterior process fractures
- Lateral process fractures (Snowboarder’s fracture)
- Crush fractures
- Talar head fractures are rare and generally associated with talonavicular dislocation/subluxation.
- Osteochondral fracture may cause loose body inside the joint which results in persistent pain and limitation of movement.
- Nonunion in fracture neck of the talus.
- Avascular necrosis of the body of the talus.
- Degenerative arthritis of the ankle.
- This is a sign seen at the end of 6-8 weeks which indicates presence of good vascularity.
- This can be clearly visualized in a mortise view as a subchondral radiolucent band in the dome of the talus.
- Fractures which are undisplaced/ displaced less than 1 mm are immobilized in plaster cast.
a) Internal fixation:
- Displaced fractures such as Types II, III and IV neck fractures;
- coronal, sagittal and horizontal shear fractures of the body are openly reduced and internally fixed.
- Arthroscopic procedures are done for removal of loose body,
- management of osteochondral lesions and in early degenerative arthritis of ankle.
- Indicated in secondary complication of nonunion, avascular necrosis and degenerative arthritis
d) Total joint arthroplasty:
- Indicated in secondary degene rative arthritis (without AVN).
e) Talectomy or Astragalectomy:
- Rarely done as it renders the ankle highly unstable.
- Avascular necrosis and non-union
- Ligament supporting the talus is Spring ligament.
- Ligament supporting the head of talus is Plantar calcaneonavicular ligament.
- Most common complication of talus fracture is Avascular necrosis.
- Fracture of talus without displacement in x-ray would lead to Osteoarthritis of ankle & Avascular necrosis of body of talus.
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