Talar fractures are the second most common tarsal bone fractures and account for approximately 0.1–0.85% of all fractures, 2% of lower extremity injuries, and 5–7% of foot injuries. Because the talus forms the mechanical link between the ankle, subtalar, and transverse tarsal joints, these injuries are clinically significant and frequently associated with long-term disability.
The talus has a unique anatomy with approximately 60–70% of its surface covered by articular cartilage and no muscular attachments. Its vascular supply depends largely on capsular and ligamentous structures, making the talus highly susceptible to osteonecrosis (avascular necrosis) after fracture displacement.
See Also: Ankle Anatomy
Anatomy of the Talus
The talus is composed of:
- Talar body
- Talar neck
- Talar head
- Lateral process
- Posterior process
The talar body articulates superiorly with the tibial plafond and transmits body weight through the ankle joint. The neck deviates medially by approximately 15–25 degrees and is the most vulnerable region to fracture.
The posterior process contains medial and lateral tubercles separated by the groove for the flexor hallucis longus (FHL) tendon.
An os trigonum may be present posteriorly in up to 50% of normal feet and may mimic a posterior process fracture on imaging.
Vascular Supply of the Talus
The blood supply arises from:
- Artery of the tarsal canal (posterior tibial artery)
- Artery of the sinus tarsi (dorsalis pedis and peroneal arteries)
- Deltoid artery
- Capsular and ligamentous vessels
Because vascularity depends on soft-tissue attachments, displaced fractures can interrupt perfusion and lead to osteonecrosis.
Epidemiology
- Talar fractures are the second most common tarsal fractures
- Talar neck fractures are the most common talar fracture subtype
- Approximately 14–26% of talar neck fractures are associated with a medial malleolus fracture
- Lateral process fractures are common in snowboarders and account for up to 15% of ankle injuries in snowboarding
- Talar head fractures are rare and comprise only 3–5% of talar fractures
Mechanism of Injury
Most talar fractures occur following high-energy trauma, including:
- Motor vehicle accidents
- Falls from height
- Sports injuries
- Snowboarding injuries
The classic mechanism for a talar neck fracture is forced hyperdorsiflexion, where the talar neck impacts the anterior tibial plafond.
Historically, talar neck fractures were called:
“Aviator’s astragalus”
because pilots sustained these injuries when crashing aircraft rudder pedals forcefully dorsiflexed the foot.
Clinical Evaluation
Patients usually present with:
- Severe ankle or hindfoot pain
- Swelling
- Inability to bear weight
- Painful ankle and subtalar motion
- Tenderness over the talus and subtalar joint
Associated injuries are common because these fractures usually result from high-energy trauma.
Important Clinical Findings
Open Fractures
Approximately 15–25% of talar fractures are open injuries.
Skin Tenting
Prolonged dislocation can compromise soft tissues and cause:
- Pressure necrosis
- Skin sloughing
- Infection
Foot Compartment Syndrome
Rare but important to recognize. Severe pain and pain with passive toe extension should raise suspicion.
Radiographic Evaluation
Standard Imaging
Initial imaging includes:
- AP ankle radiograph
- Mortise view
- Lateral ankle view
- AP and oblique foot radiographs
Canale View
The Canale view provides optimal visualization of the talar neck.
The foot is:
- Maximally plantarflexed
- Pronated 15 degrees
- X-ray beam angled 15 degrees cephalad
Computed Tomography (CT)
CT scanning is essential for:
- Detecting occult displacement
- Identifying comminution
- Assessing articular congruity
- Surgical planning
MRI
MRI may help evaluate:
- Occult fractures
- Early osteonecrosis
Classification of Talar Fractures
Talar fractures are anatomically classified into:
- Talar neck fractures
- Talar body fractures
- Talar head fractures
- Lateral process fractures
- Posterior process fractures
Talar Neck Fracture
Talar neck fractures are the most clinically important subtype because of their high risk of osteonecrosis.
Hawkins Classification
Type I
- Nondisplaced fracture
Type II
- Associated subtalar subluxation or dislocation
Type III
- Associated subtalar and ankle dislocation
Type IV
- Type III injury plus talonavicular dislocation
Download Orthopedic Classification App for Android / iOS devices
Risk of Osteonecrosis
| Hawkins Type | Osteonecrosis Risk |
|---|---|
| Type I | 0–15% |
| Type II | 20–50% |
| Type III | 50–100% |
| Type IV | Up to 100% |
Treatment of Talar Neck Fractures
Nonoperative Treatment
Indications:
- Truly nondisplaced fractures
- No subtalar incongruity on CT
Treatment includes:
- Short leg cast or boot for 8–12 weeks
- Non-weight bearing for at least 6 weeks
Some surgeons still prefer operative fixation to avoid late displacement.
Operative Treatment
Indications include:
- Displacement >2 mm
- Open fractures
- Irreducible dislocations
- Subluxation or instability
Emergency Reduction
Urgent closed reduction is required to protect:
- Soft tissues
- Blood supply
- Articular cartilage
Surgical Approaches
Common approaches include:
- Anteromedial
- Anterolateral
- Posterolateral
- Combined anteromedial-anterolateral
Internal Fixation
Fixation options include:
- Lag screws
- Headless compression screws
- Mini-fragment plates
Posterior-to-anterior screw fixation is biomechanically stronger but technically more difficult.
Bone grafting may be necessary in comminuted fractures.
Hawkins Sign
The Hawkins sign is a subchondral radiolucent band seen approximately 6–8 weeks after injury.
It indicates:
- Preserved talar vascularity
- Revascularization of the talus
Absence of the Hawkins sign may suggest osteonecrosis, although it is not completely diagnostic.
See Also: Lateral Ankle Sprain
Talar Head Fractures
Talar head fractures are uncommon injuries caused by:
- Axial loading
- Plantarflexion with longitudinal compression
These injuries are frequently associated with:
- Talonavicular instability
- Navicular fractures
- Subtalar injuries
Treatment
Nondisplaced Fractures
- Short leg cast
- Arch support
- Partial weight bearing
Displaced Fractures
- ORIF with headless screws
- Anterior or anteromedial approach
Osteonecrosis occurs in approximately 10% of cases.
Lateral Process Talar Fractures
Lateral process fractures are also known as “Snowboarder’s fractures”.
They occur from:
- Dorsiflexion
- Inversion
- External rotation
These injuries are commonly mistaken for severe ankle sprains.
Diagnosis
CT scan is frequently required because plain radiographs often miss the fracture.
Treatment
<2 mm Displacement
- Cast immobilization
- Non-weight bearing
>2 mm Displacement
- ORIF with lag screws or wires
Comminuted Fragments
- Fragment excision
Posterior Process Fracture
Posterior process fractures involve the posterior 25% of the talar articular surface.
Mechanisms include:
- Severe inversion injuries
- Forced equinus
- Direct compression
The posterolateral tubercle is more commonly involved.
Clinical Clue
Persistent posterior ankle pain after an “ankle sprain” should raise suspicion.
Treatment
Nondisplaced Fractures
- Short leg cast
- Non-weight bearing
Displaced Fractures
- ORIF if fragment is large
- Fragment excision if small
Body of Talar Fractures
Talar body fractures are distinguished from neck fractures by the location of the inferior fracture line.
Classification
Talar body fractures may be:
- Shear injuries
- Crush injuries
Treatment
Nondisplaced Fractures
- Cast immobilization
- Non-weight bearing
Displaced Fractures
- ORIF
- Possible medial malleolar osteotomy
Outcomes
Talar body fractures have high complication rates:
- Osteonecrosis
- Post-traumatic arthritis
- Malunion
- Chronic pain
Severely comminuted fractures may require:
- Talectomy
- Calcaneotibial fusion
Subtalar Dislocation
Subtalar dislocation refers to simultaneous dislocation of:
- Talocalcaneal joint
- Talonavicular joint
Types
Medial Dislocation
- Most common (up to 85%)
- Caused by inversion
Lateral Dislocation
- Caused by eversion
- Associated with worse prognosis
Management
All subtalar dislocations require urgent reduction.
Reduction Technique
- Adequate analgesia
- Knee flexion
- Longitudinal traction
- Accentuation then reversal of deformity
Reduction is usually accompanied by a palpable “clunk.”
Post-Reduction CT
CT is mandatory to evaluate:
- Osteochondral injuries
- Residual subluxation
- Intra-articular fragments
Causes of Irreducibility
Medial dislocations:
- Extensor retinaculum
- Extensor tendons
- Extensor digitorum brevis
Lateral dislocations: Posterior tibial tendon entrapment.
Complications of Talar Fractures
Osteonecrosis
Risk increases with fracture displacement.
Post-Traumatic Arthritis
Occurs in 40–90% of cases and may involve:
- Subtalar joint
- Ankle joint
- Talonavicular joint
Malunion
Commonly presents as:
- Varus deformity
- Subtalar stiffness
- Lateral foot overload
Delayed Union and Nonunion
May require:
- Revision fixation
- Bone grafting
Infection
Especially common in open fractures.
Skin Necrosis
Results from prolonged dislocation and soft-tissue compromise.
Prognosis
Outcomes depend on:
- Degree of displacement
- Articular damage
- Timing of reduction
- Soft-tissue injury
- Development of osteonecrosis
Even with optimal treatment, many patients develop:
- Chronic pain
- Stiffness
- Arthritis
- Functional limitations
Key Points
- Talar fractures are high-risk injuries because of limited vascular supply.
- Talar neck fractures are most common and carry the greatest risk of osteonecrosis.
- CT scanning is essential for fracture characterization.
- Urgent reduction is required for displaced injuries and subtalar dislocations.
- Hawkins classification predicts risk of avascular necrosis.
- Post-traumatic arthritis is a common long-term complication.
References & More
- Mulfinger GL, Trueta J. The blood supply of the talus. J Bone Joint Surg Br. 1970 Feb;52(1):160-7. PMID: 5436202. Pubmed
- Hawkins LG. Fractures of the neck of the talus. J Bone Joint Surg Am. 1970 Jul;52(5):991-1002. PMID: 5479485. Pubmed
- Canale ST, Kelly FB Jr. Fractures of the neck of the talus. Long-term evaluation of seventy-one cases. J Bone Joint Surg Am. 1978 Mar;60(2):143-56. PMID: 417084. Pubmed
- Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. J Bone Joint Surg Am. 2004 Aug;86(8):1616-24. PMID: 15292407. Pubmed
- Sanders DW, Busam M, Hattwick E, Edwards JR, McAndrew MP, Johnson KD. Functional outcomes following displaced talar neck fractures. J Orthop Trauma. 2004 May-Jun;18(5):265-70. doi: 10.1097/00005131-200405000-00001. PMID: 15105747. Pubmed
- Inokuchi S, Ogawa K, Usami N. Classification of fractures of the talus: clear differentiation between neck and body fractures. Foot Ankle Int. 1996 Dec;17(12):748-50. doi: 10.1177/107110079601701206. PMID: 8973897. Pubmed
- Vallier HA, Nork SE, Benirschke SK, Sangeorzan BJ. Surgical treatment of talar body fractures. J Bone Joint Surg Am. 2003 Sep;85(9):1716-24. doi: 10.2106/00004623-200309000-00010. PMID: 12954830. Pubmed
- Mercer’s Textbook of Orthopaedics and Trauma, Tenth edition.
