Talus Fracture (Adult)

1. Overview

Talus fractures represent a unique and challenging injury pattern in orthopaedic trauma, accounting for approximately 0.3-0.6% of all fractures but commanding disproportionate clinical attention due to their devastating potential complications. [1,2] The talus, derived from the Latin word for "ankle bone" and historically termed the "astragalus," serves as the critical mechanical link between the leg and the foot, transmitting forces across multiple articulations while possessing virtually no muscular attachments. [3]

The defining characteristic that separates talus fractures from most other skeletal injuries is the bone's precarious blood supply. Approximately 60% of the talus is covered by articular cartilage, severely limiting areas available for vascular penetration. [4] The blood supply arrives in a retrograde fashion—from distal to proximal—meaning that neck fractures disconnect the talar body from its primary nutrient vessels. This anatomical vulnerability creates the spectre of avascular necrosis (AVN), occurring in 15-100% of cases depending on fracture displacement and dislocation pattern. [5,6]

First described systematically in World War I aviators who sustained these injuries from rudder bar impacts during crashes—hence the historical term "Aviator's Astragalus"—talus fractures today result predominantly from high-energy mechanisms: motor vehicle collisions, falls from height, and industrial accidents. [7] The injury typically occurs through forced hyperdorsiflexion of the foot, driving the talar neck against the anterior tibia like a nutcracker mechanism. [8] Treatment centres on achieving anatomical reduction and stable fixation while preserving the tenuous remaining blood supply, with urgent closed or open reduction mandated when dislocation threatens skin viability.

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2. Epidemiology

Incidence and Demographics

Talus fractures demonstrate marked demographic skewing toward young adult males engaged in high-risk activities. The male predominance reflects occupational and recreational exposure patterns rather than intrinsic skeletal vulnerability. [11] Unlike osteoporotic fractures, talus fractures rarely occur from low-energy mechanisms in older populations; the typical patient profile is a male in the third or fourth decade sustaining polytrauma. [10]

Mechanism of Injury

The classic injury mechanism involves axial loading of a hyperdorsiflexed foot, creating a nutcracker effect as the anterior tibial plafond impacts the talar neck. [8] Modern mechanisms include:

1. Motor Vehicle Collision (50-60%): Dashboard or floorboard impact during deceleration, particularly affecting the right foot against the brake pedal. [12]
2. Fall from Height (20-30%): Landing on dorsiflexed foot from ≥2 metres. [14]
3. Motorcycle Collision (10-15%): Combined rotational and axial forces during impact. [15]
4. Snowboarding Injury: Particularly isolated lateral process fractures ("Snowboarder's Fracture"). [16]
5. Athletic Injury: Rare, typically basketball or football landing mechanisms. [17]

The term "Aviator's Astragalus" reflects the historical prevalence among WWI and WWII pilots whose feet became wedged against rudder pedals during crash impacts. [7] While this mechanism is now obsolete, the eponym persists in orthopaedic literature.

Risk Factors for Complications

The primary risk factor for avascular necrosis and poor outcomes is fracture displacement, with dislocation conferring catastrophic risk. [5,6] Additional risk factors include:

• Open Fracture: 15-25% of talus fractures; associated with near-100% AVN risk due to complete soft tissue stripping. [18]
• Delayed Reduction: Each hour delay > 6 hours increases AVN risk and soft tissue complications. [19]
• Ipsilateral Lower Extremity Injuries: Present in 30-40% of cases, often delaying diagnosis. [13]
• Fracture Comminution: Particularly medial neck comminution predicting varus malunion. [20]

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3. Aetiology & Pathophysiology

Anatomical Foundation

The talus is a uniquely vulnerable bone characterised by:

1. Lack of Muscular Attachments: No muscles originate from or insert on the talus, rendering it entirely dependent on ligamentous stabilisation and passive motion. [3]
2. Extensive Articular Coverage: Approximately 60% cartilage coverage limits vascular foraminal entry points. [4]
3. Seven Articular Surfaces: Superior (tibial plafond), inferior (calcaneus - posterior and middle facets), anterior (navicular), medial (medial malleolus), lateral (fibula), creating mechanical complexity. [3]
4. Retrograde Blood Supply: Nutrient flow from distal to proximal, making neck fractures catastrophic for body perfusion. [21]

Blood Supply: The Critical Vulnerability

The talar blood supply enters through three extraosseous arterial sources, all converging on the tarsal canal and sinus tarsi regions: [21,22]

1. Artery of the Tarsal Canal (Branch of Posterior Tibial Artery)

   • Main nutrient vessel to the talar body
   • Enters through the tarsal canal beneath the sustentaculum tali
   • Supplies up to 50% of talar body via intraosseous anastomoses
   • Most vulnerable to disruption in neck fractures

2. Deltoid Branch (Branch of Posterior Tibial Artery)

   • Supplies medial talar body
   • Enters through deltoid ligament attachment
   • Provides collateral circulation
   • Can be preserved with careful surgical approach

3. Artery of the Sinus Tarsi (Anastomosis of Peroneal and Dorsalis Pedis Arteries)

   • Enters through sinus tarsi
   • Supplies talar neck and head
   • Forms intraosseous anastomotic ring
   • Variable dominance pattern between individuals

Exam Detail: Intraosseous Vascular Anastomoses:

Within the talus, the three extraosseous sources form an anastomotic network with two critical patterns:

• Superior Group: Supplies the talar body and dome; primarily fed by the artery of the tarsal canal
• Inferior Group: Supplies the head and neck; primarily fed by the artery of the sinus tarsi

Fractures through the talar neck mechanically disrupt this anastomotic connection, isolating the body from its arterial inflow. The retrograde flow pattern means the body cannot receive compensation from proximal tibial vessels. Dislocation of the body from the subtalar and tibiotalar joints further strips periosteal contributions, creating complete devascularisation in Hawkins Type III-IV injuries. [21]

The venous drainage follows an inverse pattern, with intraosseous veins draining via tarsal canal and sinus tarsi channels. Fracture and dislocation create venous stasis, potentially contributing to AVN pathogenesis through ischaemia-reperfusion injury mechanisms. [22]

Mechanism of Fracture

The classic mechanism described by Anderson and Crutcher involves forced hyperdorsiflexion with axial loading: [8]

Stage 1 (Dorsiflexion): The foot is driven into maximal dorsiflexion, bringing the talar neck into contact with the anterior tibial plafond. The anterior capsule tightens, locking the talus.

Stage 2 (Impaction): Continued axial force drives the anterior tibia downward onto the fixed talar neck, creating a fulcrum. The neck fails under bending stress, typically with a dorsal tension fracture and plantar compression.

Stage 3 (Dislocation): If force continues, progressive disruption occurs:

• Subtalar joint dislocation (Hawkins Type II)
• Tibiotalar dislocation (Hawkins Type III)
• Talonavicular dislocation (Hawkins Type IV - "Extrusion Fracture")

Additional injury vectors include:

• Varus/Valgus Stress: Creates medial or lateral comminution patterns
• Rotational Forces: Particularly in motorcycle injuries, creating spiral fracture patterns
• Direct Impact: Body fractures from crush mechanisms
• Shear Forces: Lateral process and posterior process fractures

Classification Systems

Hawkins Classification (1970) - Modified by Canale and Kelly (1978)

The Hawkins classification remains the gold standard for talar neck fractures due to its prognostic value for AVN risk: [5,23]

• complete extrusion; total devascularisation |

Exam Detail: Canale and Kelly's Addition of Type IV (1978):

The original Hawkins classification described only Types I-III. Canale and Kelly added Type IV to describe the rare but catastrophic injury pattern where the talus becomes completely detached from all three articulations (tibiotalar, subtalar, talonavicular). [23] In this pattern:

• The talar body typically displaces posteromedially and can be palpated beneath the skin posterior to the medial malleolus
• All soft tissue attachments are disrupted, including ligamentous periosteal contributions
• The bone is literally "floating" outside its anatomical housing
• Immediate reduction is mandatory to prevent skin necrosis
• AVN is virtually inevitable despite optimal treatment

Displacement Threshold:

The original Hawkins paper defined "non-displaced" as less than 2mm translation or less than 5° angulation on any radiographic view. [5] Modern CT assessment often identifies subtle displacements missed on plain radiography, potentially reclassifying apparent Type I fractures. [24]

Other Fracture Pattern Classifications

Talar Body Fractures (Less Common):

• Crush/comminution patterns
• Osteochondral dome fractures (Berndt and Harty classification)
• Vertical shear fractures

Lateral Process Fractures ("Snowboarder's Fracture"):

• Type I: Simple fracture
• Type II: Comminuted fracture
• Often missed on initial ankle radiographs; requires CT for diagnosis [16]

Posterior Process Fractures:

• Stieda process fracture vs. os trigonum (congenital accessory ossicle)
• Differentiated by corticated margins (os trigonum) vs. fracture line

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4. Clinical Presentation

Symptoms

Cardinal Symptoms:

• Severe Hindfoot Pain (100%): Immediate onset at injury; typically described as "crushing" or "bursting" quality
• Inability to Weight-Bear (100%): Complete functional impairment
• Swelling (95-100%): Rapid diffuse ankle and hindfoot swelling within hours

Associated Symptoms:

• Paraesthesia (15-25%): Suggests nerve contusion or compartment syndrome
• Mechanical symptoms: Locking or grinding if loose fragments present (rare acutely due to swelling)

Red Flag Symptoms Requiring Emergency Assessment:

• Progressive swelling despite elevation and ice (compartment syndrome)
• Burning pain disproportionate to apparent injury (complex regional pain syndrome)
• Numbness in tibial or sural nerve distribution (nerve injury)

Signs

General Inspection:

• Gross Swelling: Diffuse ankle and hindfoot oedema, often obliterating normal anatomical landmarks within 2-4 hours
• Ecchymosis: May be delayed 12-24 hours; medial, lateral, and plantar bruising patterns
• Deformity: Present in Types III-IV with visible or palpable talar body displacement

Specific Examination Findings:

Neurovascular Assessment:

• Dorsalis Pedis Pulse: Usually palpable unless displaced bone causes kinking
• Posterior Tibial Pulse: Frequently diminished or absent with medial body displacement
• Sensation: Test tibial nerve (plantar foot), superficial peroneal (dorsum), sural (lateral), deep peroneal (1st web space)
• Motor: Limited by pain; document toe flexion/extension if possible

Exam Detail: Compartment Syndrome Risk:

The foot contains nine compartments (medial, central, lateral, and interosseous spaces). Talus fractures with associated calcaneal or midfoot injuries increase compartment syndrome risk to 10-15%. [25] Clinical diagnosis relies on the "5 Ps":

• Pain: Disproportionate and progressive despite analgesia
• Pressure: Firm, tense compartments on palpation
• Paraesthesia: Nerve compression causing sensory loss
• Pallor: Late sign; indicates arterial compromise
• Pulselessness: Late and ominous; immediate surgical decompression required
• Pain with Passive Stretch: Most sensitive early sign (e.g., pain with passive toe dorsiflexion suggests deep posterior compartment syndrome)

Threshold for formal compartment pressure measurement should be low. Pressures > 30 mmHg or within 30 mmHg of diastolic blood pressure warrant fasciotomy. [25]

Clinical Examination Sequence (OSCE Scenario)

Approach to Suspected Talus Fracture:

1. History: Mechanism (high-energy?), timing, immediate deformity, paraesthesia
2. Inspection: Swelling pattern, deformity, skin integrity, fracture blisters
3. Palpation: Systematic palpation of malleoli, talar body, hindfoot, compartments
4. Neurovascular: Pulses, sensation, motor (document carefully)
5. Special Tests (limited by pain):
   • Ankle range of motion (usually impossible)
   • Subtalar motion (inversion/eversion)
   • Squeeze test (syndesmosis - associated injury)
6. Associated Injuries: Examine ipsilateral knee, femur, pelvis (30-40% have other fractures) [13]

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5. Differential Diagnosis

Talus fractures are frequently misdiagnosed initially, particularly in polytrauma patients or when undisplaced. [26] Consider:

Primary Differentials

Must-Not-Miss Diagnoses

1. Subtalar Dislocation Without Fracture: Requires emergency reduction; excellent prognosis if reduced promptly
2. Open Fracture: Breaks in skin may be subtle; always examine plantar surface; contamination → AVN
3. Compartment Syndrome: Progressive pain despite immobilisation and analgesia
4. Associated Spine Injury: Fall from height → 10% have thoracolumbar fracture [27]

Commonly Missed Talus Fracture Patterns

• Lateral Process Fracture: Missed in up to 40% of cases on initial ankle radiographs; requires dedicated foot views or CT [16]
• Posterior Process Fracture: Confused with os trigonum (accessory ossicle); differentiate by sharp fracture line vs. rounded corticated margins
• Osteochondral Dome Fracture: Subtle on plain radiographs; requires CT or MRI; may present weeks later with mechanical symptoms

Clinical Pearl: The "Sprained Ankle That Doesn't Heal":

Lateral process fractures, representing 15-20% of all talus fractures, are frequently diagnosed initially as "ankle sprain." [16] Patients treated with conservative management for presumed sprain who fail to improve at 4-6 weeks should undergo CT imaging to exclude this diagnosis. Delayed diagnosis leads to nonunion in 30-50% and chronic subtalar arthritis.

Pearl: In any ankle injury where tenderness is lateral and inferior to the fibular tip (rather than over the anterior talofibular ligament), consider lateral process fracture and obtain oblique foot radiographs or CT.

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6. Investigations

First-Line Imaging

Plain Radiographs (Ankle and Foot Series):

Standard Views Required:

1. Ankle AP, Lateral, Mortise: Assesses tibiotalar joint, identifies neck/body fractures
2. Foot AP, Lateral, Oblique: Profiles talar head, lateral process, visualises navicular relationship
3. Canale View (Dedicated Talar Neck View): Essential for surgical planning

Exam Detail: The Canale View Technique:

Described by Canale and Kelly in 1978, this view is the only radiographic projection that truly profiles the talar neck in its long axis, allowing accurate assessment of displacement and comminution. [23]

Patient Positioning:

• Ankle in maximum equinus (plantarflexion)
• Foot pronated 15° (internal rotation)
• X-ray beam angled 75° cephalad from vertical
• Centered on talar neck

What It Shows:

• True neck profile (no overlap with malleoli)
• Medial comminution (predicts varus malunion)
• Fracture displacement magnitude
• Screw trajectory planning

Common Error: Insufficient cephalad beam angle results in overlap with tibial plafond, obscuring fracture details.

Exam Viva Point: When asked about investigating talus neck fracture, specifically mention the Canale view by name—examiners recognise this as a knowledge marker for foot and ankle trauma expertise.

Radiographic Signs:

Second-Line/Gold Standard Imaging

CT Scan (Mandatory for All Surgical Cases):

CT has become the gold standard for characterising talus fractures and is universally recommended before surgical intervention. [24,28]

Indications:

• All displaced fractures (planning operative fixation)
• Suspected lateral/posterior process fractures (frequently occult on X-ray)
• Post-reduction assessment (confirm joint congruency)
• Subtle fractures in high-suspicion cases

Technique:

• Fine-cut (≤1mm) axial slices
• Coronal and sagittal reconstructions
• 3D volume rendering for surgical planning

Information Provided:

• Fracture pattern and comminution degree
• Articular surface step-off (less than 2mm acceptable)
• Associated osteochondral injuries
• Screw trajectory planning
• Assessment of subtalar/talonavicular joint alignment

MRI Imaging:

Indications:

• Assessing for early AVN (delayed presentation)
• Occult fracture (high suspicion, negative X-ray/CT)
• Osteochondral lesion characterisation
• Chronic pain post-fracture

MRI Findings in AVN:

• T1-weighted: Diffuse low signal in talar body (marrow oedema/necrosis)
• T2-weighted: Variable signal depending on stage
• Gadolinium enhancement: Absence of enhancement confirms AVN

The Hawkins Sign (Prognostic Imaging Finding)

The Hawkins Sign is a critical radiographic finding assessed at 6-8 weeks post-injury on standard AP ankle radiograph: [5]

Appearance: Subchondral radiolucent line (area of decreased bone density) beneath the talar dome articular surface

Interpretation:

• Sign Present (radiolucent line visible): Indicates disuse osteopenia from hyperaemia → Blood supply is intact → Good prognosis (AVN unlikely)
• Sign Absent (no radiolucency; bone appears normal or sclerotic): Suggests absence of vascular response → AVN likely

Diagnostic Performance:

• Sensitivity for AVN: Absence of sign ~80% sensitive for AVN
• Specificity for vascular survival: Presence of sign ~100% predictive of viability [5]

Clinical Application: Guides weight-bearing progression and patient counselling regarding AVN risk

Exam Detail: Pathophysiology of Hawkins Sign:

The Hawkins sign represents a positive prognostic indicator through a counterintuitive radiographic appearance. Following fracture, viable bone undergoes disuse osteopenia due to immobilisation and protected weight-bearing. This osteopenia reflects active bone remodelling—osteoclastic resorption exceeding osteoblastic formation—which requires an intact vascular supply delivering osteoclasts to the site. [5]

The subchondral location is most conspicuous because:

1. Thin trabecular bone in this region shows demineralisation earliest
2. Absence of overlying structures allows clear visualisation
3. Mechanical unloading is maximal at the articular surface

Conversely, in AVN:

• Necrotic bone cannot undergo remodelling
• Dead trabeculae retain their mineralisation
• Bone appears normal or increased density (relatively sclerotic compared to living bone)
• As surrounding viable bone demineralises, the necrotic area becomes relatively radiodense

Timeline: The sign typically appears between 6-8 weeks. Earlier assessment may be falsely negative; later assessment may show sclerosis if AVN is present.

Limitations:

• Absence of sign is not 100% specific for AVN (some viable bone may not show osteopenia)
• Delayed weight-bearing can delay sign appearance
• Most useful in Hawkins Type II-III fractures

Modern Adjunct: MRI can detect AVN earlier (3-4 weeks) and with greater sensitivity, but Hawkins sign remains a valuable clinical tool due to its simplicity and prognostic reliability.

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7. Management

The management of talus fractures is dictated by fracture type, displacement, and urgency of soft tissue compromise. The overarching principles are:

1. Emergency reduction if dislocation threatens skin viability
2. Anatomical reduction to restore joint congruity
3. Stable fixation to allow early motion and maximise revascularisation
4. Soft tissue respect to preserve remaining blood supply

Management Algorithm

                    TALUS FRACTURE SUSPECTED
                              ↓
                    IMMEDIATE ASSESSMENT
                  (Neurovascular, Skin Threat)
                              ↓
              ┌───────────────┴───────────────┐
              ↓                               ↓
    DISLOCATION PRESENT               NO DISLOCATION
    (Type III/IV)                     (Type I/II)
              ↓                               ↓
    SKIN THREAT?                      PLAIN RADIOGRAPHS
    Tenting/ischaemia?                (AP, Lat, Mortise, Canale)
              ↓                               ↓
         YES  |  NO                      CT SCAN (Mandatory)
              ↓  ↓                             ↓
    EMERGENCY    POST-REDUCTION         HAWKINS CLASSIFICATION
    REDUCTION    CT WITHIN 24H                 ↓
    (Sedation ED;            ┌─────────────────┼─────────────────┐
     Open if fails)          ↓                 ↓                 ↓
              ↓          TYPE I           TYPE II          TYPE III/IV
              └────────►NON-DISPLACED     DISPLACED        DISPLACED +
                        (less than 2mm, less than 5°)       ±Subtalar         DISLOCATED
                             ↓                ↓                  ↓
                        CONSERVATIVE      OPERATIVE          OPERATIVE
                        MANAGEMENT        FIXATION           FIXATION
                        - Cast NWB        (Urgent - within   (Emergency - same
                        - 8-12 weeks      3-7 days)          day if open; within
                        - Weekly X-ray                       24-48h if closed)
                        ×3 weeks                                 ↓
                             └────────────────┬──────────────────┘
                                              ↓
                                    POST-OP REHABILITATION
                                    - Cast NWB 6-8 weeks
                                    - Progressive WB if Hawkins sign +
                                    - X-ray at 6-8w (Hawkins sign)
                                    - Long-term AVN surveillance

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8. Management: Acute/Emergency

Emergency Reduction Indications

Absolute Indications (Within 6 Hours):

1. Skin Tenting: Imminent necrosis from bony pressure
2. Gross Deformity: Type III/IV fracture-dislocations
3. Vascular Compromise: Absent pulses with limb ischaemia
4. Open Fracture: Reduction facilitates wound management

Relative Indications:

• Any dislocation (Type II-IV) even without immediate skin threat
• Compartment syndrome suspected

Emergency Reduction Technique

Closed Reduction (Attempt First):

Setting: Emergency Department with procedural sedation (propofol or ketamine) or operating theatre under general anaesthesia

Technique (for posteromedial body displacement - most common):

1. Positioning: Patient supine, knee flexed 90° to relax gastrocnemius
2. Traction: Assistant applies longitudinal traction on heel
3. Manipulation:
   • Plantarflex foot maximally (unlocks ankle)
   • Apply direct pressure to palpable talar body, pushing anterolaterally
   • Simultaneously dorsiflex foot and evert hindfoot
   • "Reduce talus into mortise like closing a book"
4. Assessment: Palpate for body reduction; assess pulses immediately
5. Immobilisation: Well-padded posterior slab in neutral position

Post-Reduction Protocol:

• Immediate neurovascular reassessment
• Post-reduction radiographs (AP, lateral, mortise)
• Post-reduction CT within 24 hours (mandatory to assess joint congruency and plan surgery)
• Admit for observation (compartment syndrome surveillance)
• Elevation, ice, analgesia

Open Reduction:

Indications:

• Failed closed reduction (irreducible soft tissue/bony interposition)
• Open fracture (combine with debridement)
• Vascular injury requiring repair

Timing: Proceed immediately if closed reduction fails

Open Fracture Management

Open talus fractures represent a surgical emergency due to contamination eliminating the already-compromised blood supply. [18]

Protocol (per BOAST 4 Guidelines):

1. Immediate Actions:
   • Photograph wound; cover with saline-soaked gauze
   • IV antibiotics within 1 hour (co-amoxiclav 1.2g or cefuroxime 1.5g)
   • Tetanus prophylaxis
2. Theatre Within 6 Hours:
   • Formal irrigation and debridement
   • Reduction and provisional fixation
   • Leave wound open or loosely approximate (definitive closure at 48-72h)
3. Antibiotic Duration: Gustilo grade-dependent (Type I: 24h; Type II/III: 72h)

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9. Management: Conservative (Non-Operative)

Indications

Strict Criteria for Non-Operative Treatment:

1. Hawkins Type I fracture with:

   • Displacement less than 2mm on all views (including Canale view)
   • Angulation less than 5° in all planes
   • CT-confirmed non-displacement
   • No associated injuries requiring surgery

2. Patient Factors:

   • Medical comorbidities precluding safe anaesthesia
   • Non-ambulatory at baseline (limited functional demand)
   • Patient refusal of surgery

Contraindications:

• Any displacement ≥2mm (unacceptable articular step-off)
• Hawkins Type II-IV (dislocation)
• Associated injuries requiring operative fixation

Conservative Protocol

Immobilisation:

• Initial: Below-knee backslab (allow swelling accommodation)
• Definitive (after swelling subsides, ~5-7 days): Below-knee cast in neutral dorsiflexion

Weight-Bearing Restriction:

• Non-Weight-Bearing (NWB) mandatory: 8-12 weeks
• Crutch mobilisation; knee scooter alternative
• No progressive weight-bearing until radiographic union

Monitoring:

• Weeks 1, 2, 3: Weekly radiographs (AP, lateral, Canale) to detect displacement
• If displacement occurs: Convert to operative fixation immediately
• Week 6-8: Assess Hawkins sign
• Week 12: CT to confirm union; begin protected weight-bearing if healed

Union Criteria:

• Bridging trabeculae across fracture on CT
• No pain with palpation
• Hawkins sign present (good prognostic indicator)

Outcomes:

• Hawkins Type I fractures treated non-operatively: Union rate > 95%, AVN rate less than 15% if truly non-displaced [6]
• Displacement during treatment: Occurs in 5-10%; requires conversion to ORIF

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10. Management: Operative

Operative fixation is indicated for all displaced fractures (Hawkins Type II-IV) and is considered the standard of care for Type II-IV injuries. [6,29]

Surgical Timing

Emergency Surgery (Within 6-12 Hours):

• Open fractures (after debridement)
• Irreducible dislocations
• Compartment syndrome (fasciotomy ± fixation)

Urgent Surgery (Within 24-48 Hours):

• Hawkins Type III-IV (after successful closed reduction and soft tissue assessment)

Delayed Surgery (3-7 Days):

• Hawkins Type II
• Allows soft tissue swelling resolution
• Proceed when fracture blisters re-epithelialised

Timing Evidence: Historical dogma advocated "surgery within 6 hours to save blood supply," but modern evidence shows that immediate reduction of dislocation is critical; definitive fixation can be delayed safely until soft tissues permit, provided the joint remains reduced. [30]

Surgical Goals

1. Anatomical Reduction: Restore articular congruity (step-off less than 2mm)
2. Rigid Fixation: Allow early motion while protecting blood supply revascularisation
3. Preserve Blood Supply: Minimise soft tissue stripping; protect deltoid/sinus tarsi vessels
4. Avoid Hardware Prominence: Prevent impingement and enable future salvage procedures

Surgical Approaches

The choice of approach depends on fracture location and comminution pattern. Many neck fractures require dual approaches for adequate visualisation and fixation.

1. Anteromedial Approach

Indications:

• Primary approach for talar neck fractures
• Allows access to medial comminution (requires buttressing)
• Enables visualization of medial neurovascular bundle

Incision:

• Longitudinal over talar neck, medial to tibialis anterior tendon
• Extends from tibial plafond to navicular

Interval:

• Between tibialis anterior (lateral) and neurovascular bundle (medial)

Structures at Risk:

• Saphenous vein and nerve (retract medially)
• Deltoid artery branches (preserve for blood supply)
• Deep deltoid ligament (avoid stripping)

Exposure Achieved:

• Medial talar neck
• Medial talar body
• Talonavicular joint

2. Anterolateral Approach

Indications:

• Access to lateral talar neck
• Visualization of sinus tarsi (assess vascular injury)
• Removal of bony/soft tissue blocks to reduction

Incision:

• Longitudinal, lateral to extensor digitorum longus tendon

Interval:

• Between extensor digitorum longus and peroneus tertius

Exposure Achieved:

• Lateral talar neck
• Sinus tarsi
• Anterior process of calcaneus
• Lateral talar body

3. Posterolateral Approach (Less Common)

Indications:

• Posterior body fractures
• Posterior malleolar fractures (associated injury)
• Posterior screw insertion

Interval:

• Between peroneal tendons (lateral) and flexor hallucis longus (medial)

Fixation Techniques

Lag Screw Fixation (Standard for Neck Fractures)

Screw Configuration:

• Number: Minimum 2 screws; 3 screws if comminution present
• Size: 3.5mm or 4.0mm cortical or cannulated screws
• Direction: Controversial - each has advantages

Posterior-to-Anterior (PA) Screws:

• Advantages: Biomechanically superior compression; avoids impingement on talar head cartilage
• Disadvantages: Technically demanding; risk of injury to neurovascular bundle; often requires prone positioning
• Technique: Percutaneous insertion through posterior body, crossing fracture to purchase in head/neck

Anterior-to-Posterior (AP) Screws:

• Advantages: Easier insertion; anatomical approach allows direct reduction
• Disadvantages: Screw heads can impinge on navicular; prominence at talar head; limits intramedullary purchase
• Technique: Open or percutaneous from talar head/neck into body

Modern Consensus: Most surgeons use AP screws for simplicity, accepting slight biomechanical inferiority. PA screws reserved for skilled foot/ankle specialists. [29]

Plate Fixation

Indications:

• Medial Comminution: Requires buttress plating to prevent varus collapse [20]
• Shear Fractures: Vertical fracture patterns resist screw fixation alone
• Nonunion: Revision surgery with bone grafting

Technique:

• Mini-fragment (2.0-2.7mm) medial plate via anteromedial approach
• Functions as buttress plate (not compression)
• Combined with lag screws for optimal stability

Evidence: Studies demonstrate medial plating reduces varus malunion from 25% to less than 10% when medial comminution present. [20]

Operative Sequence

1. Positioning: Supine with bump under ipsilateral hip
2. Approach: Anteromedial first; add anterolateral if needed
3. Reduction:
   • Clear fracture haematoma and debris
   • Reduce under direct vision
   • Provisional fixation with K-wires
   • Confirm reduction with fluoroscopy (AP, lateral, mortise, Canale)
4. Definitive Fixation:
   • Insert lag screws perpendicular to fracture plane
   • Achieve compression across fracture
   • Add medial plate if comminution present
5. Closure: Layered; drain optional
6. Immobilisation: Below-knee backslab in neutral

Post-Operative Protocol

Immobilisation:

• Below-knee cast: 6-8 weeks

Weight-Bearing:

• Non-Weight-Bearing (NWB): 6-8 weeks minimum
• Partial Weight-Bearing: Begin if Hawkins sign present at 6-8 weeks
• Full Weight-Bearing: 12-16 weeks if radiographic union confirmed

Radiographic Surveillance:

• Week 2: Wound check and radiographs
• Week 6-8: Radiographs for Hawkins sign and early union
• Week 12: CT to confirm union
• Annually for 3 years: Screen for AVN and arthritis

Rehabilitation:

• Phase 1 (0-6 weeks): Immobilisation, NWB
• Phase 2 (6-12 weeks): Gentle ankle/subtalar ROM exercises; progressive WB
• Phase 3 (12-24 weeks): Strengthening, proprioception training
• Return to Activity: 6-12 months depending on AVN presence

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11. Complications

Talus fractures carry one of the highest complication rates of any skeletal injury, with AVN dominating long-term outcomes. [6]

Avascular Necrosis (AVN)

Incidence by Hawkins Type:

Pathophysiology: Fracture disrupts retrograde arterial inflow; body undergoes ischaemic necrosis; dead trabecular bone collapses under weight-bearing stress.

Clinical Presentation:

• Early: Often asymptomatic
• Late: Progressive pain, stiffness, inability to weight-bear

Diagnosis:

• Radiographs: Sclerosis (increased density) of talar dome; later shows collapse and fragmentation
• Hawkins Sign Absence: At 6-8 weeks suggests AVN
• MRI: Diffuse low T1 signal; diagnostic within 6-12 weeks

Natural History:

• Revascularisation Possible: Some cases undergo "creeping substitution" (new vessels invade; new bone replaces dead bone) over 18-36 months
• Collapse Common: 40-60% progress to dome collapse despite revascularisation attempts

Management:

• Protected Weight-Bearing: NWB or PWB for 12-24 months to allow revascularisation
• Surveillance: Serial radiographs every 3 months
• Surgical Options if Collapse:
  • "Core Decompression: Controversial; limited evidence"
  • "Vascularised Bone Grafting: Case reports only"
  • "Blair Fusion: Tibiotalocalcaneal arthrodesis; salvage procedure"
  • "Ankle Replacement: Controversial; high failure rate in AVN setting"
  • "Below-Knee Amputation: Ultimate salvage if intractable pain"

Post-Traumatic Arthritis

Incidence: 40-90% of displaced fractures develop arthritis within 5-10 years [31]

Joints Affected:

• Subtalar Joint (Most Common): 50-80% of Hawkins Type II-III
• Tibiotalar (Ankle) Joint: 40-60% of Type III-IV
• Talonavicular Joint: 20-30% of cases

Risk Factors:

• Articular incongruity (step-off > 2mm)
• AVN
• Malunion
• Prolonged immobilisation

Management:

• Conservative: NSAIDs, activity modification, bracing, intra-articular steroid injections
• Surgical:
  • "Subtalar Arthritis: Subtalar fusion (excellent pain relief; minimal functional loss)"
  • "Ankle Arthritis: Ankle arthrodesis (gold standard) or total ankle replacement (selected cases)"
  • "Pantalar Arthritis: Tibiotalocalcaneal fusion (major salvage procedure)"

Malunion

Varus Malunion (Most Common Pattern):

Mechanism: Medial neck comminution collapses → talar body tilts into varus → heel inverted

Clinical Impact:

• Locks subtalar joint (cannot evert)
• Forces weight-bearing onto lateral border of foot
• Peroneal tendon overload and pain
• Progressive lateral ankle instability

Incidence: 15-25% of operatively treated neck fractures; higher if medial comminution not buttressed [20]

Management:

• Symptomatic: Osteotomy (opening wedge medial neck osteotomy + bone graft + plate)
• Arthritic: Subtalar or tibiotalocalcaneal fusion in corrected alignment

Valgus Malunion (Rare):

• Opposite deformity; medial column overload

Nonunion

Incidence: 5-10% of operatively treated fractures [32]

Risk Factors:

• Inadequate fixation
• AVN (nonviable bone cannot heal)
• Infection
• Smoking

Presentation: Persistent pain at fracture site; inability to progress weight-bearing

Diagnosis: CT at 6 months showing persistent fracture line, no bridging trabeculae

Management:

• Revision ORIF: Debridement, bone grafting (autograft from iliac crest), rigid fixation (plate + screws)
• Salvage: Tibiotalocalcaneal fusion if AVN coexists

Infection

Incidence:

• Closed fractures: less than 5%
• Open fractures: 15-40% depending on Gustilo grade [18]

Organisms:

• Early (less than 2 weeks): Staphylococcus aureus, Streptococcus species
• Late: Polymicrobial; consider Pseudomonas in open injuries

Management:

• Acute: Debridement, antibiotic therapy (6-12 weeks IV), retain hardware if stable
• Chronic Osteomyelitis: Staged reconstruction (debridement + antibiotic spacer → delayed fusion)

Compartment Syndrome

Incidence: 10% in high-energy talus fractures with associated injuries [25]

Compartments of Foot: 9 compartments (medial, central, lateral, four interosseous, calcaneal, adductor)

Diagnosis: Clinical (5 Ps); compartment pressure > 30 mmHg

Management: Emergency fasciotomy (all compartments); delayed wound closure or skin grafting

Wound Complications

Fracture Blisters:

• Occur in 15-30% of high-energy injuries
• Delay surgery until re-epithelialised (5-10 days)

Skin Necrosis:

• From delayed reduction or surgical approach trauma
• May require flap coverage

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12. Prognosis

Overall Outcomes

Talus fractures carry a guarded prognosis, with outcomes heavily dependent on fracture type and achievement of anatomical reduction:

Prognostic Factors

Favourable Prognostic Factors:

• Non-displaced fracture (Hawkins Type I)
• Anatomical reduction achieved (articular step less than 2mm)
• Early reduction of dislocation (less than 6 hours)
• Closed injury
• Isolated injury (no polytrauma)
• Presence of Hawkins sign at 6-8 weeks

Adverse Prognostic Factors:

• High-energy mechanism
• Open fracture
• Delayed reduction (> 6 hours to reduce dislocation)
• Articular incongruity (step-off > 2mm)
• Comminution
• AVN development
• Infection

Long-Term Function

Studies with 10-20 year follow-up demonstrate: [31,33]

• 50-60% of patients report persistent functional limitation
• 40% have chronic pain requiring regular analgesia
• 30-40% require arthrodesis procedures
• Return to manual labour: 40-60%
• Return to high-level athletics: less than 20%

Factors Associated with Better Long-Term Function:

• Anatomical reduction
• Absence of AVN
• Hawkins Type I-II (vs. III-IV)
• Age less than 40 years at injury

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13. Prevention & Screening

Talus fractures are typically traumatic injuries with limited primary prevention opportunities beyond general injury prevention strategies:

Primary Prevention

• Motor Vehicle Safety: Seat belt use; airbag deployment; vehicle safety standards
• Fall Prevention: Workplace safety regulations (scaffolding, harnesses); height restrictions
• Sports Safety: Protective equipment in high-risk sports (snowboarding wrist guards reduce upper extremity fractures but not talus fractures)

Secondary Prevention (Preventing Complications)

• Early Recognition: High index of suspicion in ankle trauma; obtain CT for subtle injuries
• Emergency Reduction: Reduce dislocations within 6 hours
• Anatomical Reduction: Achieve less than 2mm articular step-off surgically
• Protected Weight-Bearing: Strict NWB until union confirmed; prevents AVN collapse
• Hawkins Sign Monitoring: Guide weight-bearing progression

Screening

No population screening applicable; diagnosis is injury-based.

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14. Key Guidelines & Evidence

Landmark Studies

1. Hawkins LG (1970): Original description of Hawkins Classification and prognostic sign. Established AVN risk stratification by fracture type. [5]

2. Canale ST, Kelly FB (1978): Added Hawkins Type IV; described the Canale radiographic view; reported long-term outcomes in 71 cases. [23]

3. Vallier HA et al. (2004): Modern case series of 102 talar neck fractures; demonstrated importance of anatomical reduction and early fixation. [6]

4. Lindvall et al. (2004): Systematic review of 868 fractures; confirmed AVN rates by Hawkins type; identified open fracture as major risk factor. [18]

Current Guidelines

British Orthopaedic Association (BOAST Guidelines):

• BOAST 4: Open fracture management (immediate antibiotics, debridement within 6 hours)

AO Foundation Principles:

• Anatomical reduction is mandatory for articular fractures
• Stable fixation allows early mobilisation
• Preserve soft tissue and blood supply

Consensus Recommendations (based on systematic reviews): [29,34]

• CT imaging mandatory for all displaced fractures
• Operative fixation for displacement > 2mm
• Emergency reduction for dislocation within 6 hours
• Dual surgical approaches often required for adequate reduction
• Medial plating for medial comminution
• Non-weight-bearing for minimum 8 weeks post-operatively
• Long-term surveillance (minimum 2 years) for AVN and arthritis

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15. Common Exam Questions (MRCS/FRCS)

Written Exam (MCQ/SBA) High-Yield Topics

1. Hawkins Classification: Know AVN risk percentages for each type
2. Blood Supply: Name three arterial sources; explain retrograde pattern
3. Hawkins Sign: Timing (6-8 weeks), appearance (subchondral lucency), interpretation (presence = good prognosis)
4. Canale View: Positioning (equinus + 15° pronation + 75° cephalad beam)
5. Complications: AVN most common; malunion (varus) second

Clinical/Viva Scenarios

Scenario 1: "A 35-year-old male has fallen from 3 metres onto his right foot. The ankle is grossly swollen with a palpable bony prominence posteromedial to the medial malleolus. How do you manage this?"

Model Answer: "This presentation suggests a displaced talus fracture with possible Type III or IV fracture-dislocation. My immediate priorities are:

1. Assessment: Neurovascular status—check dorsalis pedis and posterior tibial pulses; assess sensation in tibial, sural, superficial and deep peroneal distributions; inspect skin for tenting or threatened necrosis.

2. Emergency Reduction: This is a time-critical injury. Skin tenting risks necrosis within 6 hours. I would arrange immediate reduction either in the Emergency Department under procedural sedation or in theatre under general anaesthesia depending on local protocols and patient factors.

3. Reduction Technique: With the knee flexed to relax gastrocnemius, apply longitudinal traction, plantarflex maximally to unlock the ankle, then apply direct pressure to the palpable talar body pushing anterolaterally while dorsiflexing and everting the foot.

4. Post-Reduction:

   • Reassess neurovascular status
   • Radiographs to confirm reduction (AP, lateral, mortise)
   • CT within 24 hours to assess joint congruency and plan definitive fixation
   • Admission for observation and elevation
   • Definitive operative fixation within 24-48 hours

5. Definitive Management: Likely ORIF via anteromedial ± anterolateral approach with lag screw fixation ± medial plate if comminuted, followed by 6-8 weeks non-weight-bearing in cast.

6. Counselling: Explain high risk of avascular necrosis (50-100% in Type III-IV) and need for long-term surveillance."

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Scenario 2: "What is the Hawkins sign and what does it tell you?"

Model Answer: "The Hawkins sign is a prognostic radiographic finding seen at 6-8 weeks post-injury on a standard AP ankle radiograph.

Appearance: It is a subchondral radiolucent line beneath the talar dome articular surface.

Pathophysiology: It represents disuse osteopenia. When the talus has an intact blood supply, immobilisation and non-weight-bearing cause osteoclastic resorption to exceed osteoblastic formation. This creates visible demineralisation, most apparent in the thin subchondral trabecular bone.

Interpretation:

• Presence of sign (radiolucency visible): The bone is alive and undergoing active remodelling. This is a positive prognostic indicator—avascular necrosis is unlikely.
• Absence of sign (no lucency; bone appears normal or sclerotic): Suggests the bone is not undergoing active remodelling, indicating possible AVN.

Predictive Value: Presence of the Hawkins sign is nearly 100% predictive that the talar body will remain viable. However, absence is only approximately 80% sensitive for AVN—some viable bone may not show the sign.

Clinical Application: If the Hawkins sign is present at 6-8 weeks, I can reassure the patient regarding AVN risk and begin cautious progressive weight-bearing. If absent, I maintain protected weight-bearing and arrange MRI for definitive AVN assessment."

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Scenario 3: "How do you perform a Canale view and why is it important?"

Model Answer: "The Canale view is a dedicated radiographic projection described by Canale and Kelly in 1978 specifically for assessing talar neck fractures.

Technique:

• Position the ankle in maximum plantarflexion (equinus)
• Pronate (internally rotate) the foot 15 degrees
• Angle the X-ray beam 75 degrees cephalad from the vertical
• Center the beam on the talar neck

Purpose: This is the only radiographic view that truly profiles the talar neck in its long axis without overlap from the tibial plafond or malleoli.

Information Provided:

1. Displacement Assessment: Accurately measures fracture displacement in the plane most relevant to AVN risk
2. Comminution Detection: Reveals medial neck comminution which predicts varus malunion risk
3. Surgical Planning: Allows planning of screw trajectory to achieve optimal purchase and compression

Clinical Importance: Without the Canale view, significant displacement may be missed on standard views, leading to inappropriate conservative management. It is essential for both diagnosis and surgical planning in talar neck fractures.

Common Mistake: Insufficient cephalad beam angle (e.g., only 45-60°) results in persistent tibial overlap and defeats the purpose of the view."

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Common Mistakes That Fail Candidates

❌ Mistake 1: Describing the Hawkins sign as "sclerosis" (this is AVN, not the Hawkins sign)

✅ Correction: Hawkins sign is subchondral lucency (radiolucent line) indicating viability

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❌ Mistake 2: Recommending immediate ORIF for a Type III fracture-dislocation presenting with skin tenting

✅ Correction: Emergency reduction first (within 6 hours to save skin); definitive ORIF can wait 24-48 hours after soft tissues assessed

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❌ Mistake 3: Stating "talus has no blood supply"

✅ Correction: Talus has a precarious retrograde blood supply from three vessels (tarsal canal, deltoid branch, sinus tarsi); fracture disrupts this, causing AVN risk

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❌ Mistake 4: Accepting 3-4mm displacement in a talar neck fracture for conservative treatment

✅ Correction: Displacement threshold is less than 2mm; anything ≥2mm requires operative fixation

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❌ Mistake 5: Failing to mention the Canale view when discussing talar neck fracture investigation

✅ Correction: Always mention Canale view specifically—it's a knowledge marker examiners look for

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16. Patient Explanation (Layperson Language)

The Injury

You have broken the talus, which is the small bone that sits between your ankle and your heel. It's a critical bone because it acts like a mechanical bridge, allowing your foot to move up and down and side to side. Breaking it is rare but serious.

Why Is It Serious?

The talus has a poor blood supply. Unlike most bones, which have multiple blood vessels feeding them, the talus relies on just a few small arteries. When the bone breaks, especially if it moves out of position, these blood vessels can be torn or kinked. If blood can't reach parts of the bone, that section can "die"—a condition called avascular necrosis or AVN.

The Treatment

We need to put the bone back into perfect position and hold it there with screws. This gives the best chance for the blood vessels to reconnect and the bone to heal. You'll be in a cast and unable to put weight on your foot for about 8-12 weeks. This period is critical to protect the bone while it heals.

What to Expect

Short term (0-3 months):

• You'll need crutches or a knee scooter to get around
• Regular X-rays to check healing
• Pain will gradually improve over 6-12 weeks

Medium term (3-12 months):

• Gradual return to walking
• Physical therapy to regain strength and motion
• At 6-8 weeks, we'll take a special X-ray looking for a "Hawkins sign"—a faint line on the X-ray that tells us the bone is alive and healing (good news!)

Long term (1-3 years):

• Regular monitoring for complications
• Some stiffness of the ankle and foot is common
• About 15-50% of patients develop AVN despite perfect treatment (risk depends on severity of initial injury)
• If AVN occurs, additional surgery may be needed later (fusion of the ankle or hindfoot joints)

Realistic Outcomes

• Best case (non-displaced fractures): 80-90% return to normal activities
• Moderate case (displaced but reduced): 50-70% return to previous function
• Severe case (dislocated fractures): 30-50% have long-term limitations; may need further surgery

Most patients have some permanent limitations in high-impact activities (running, jumping) but can return to normal walking and daily activities.

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17. References

1. Sneppen O, Christensen SB, Krogsøe O, Lorentzen J. Fracture of the body of the talus. Acta Orthop Scand. 1977;48(3):317-324. doi:10.3109/17453677708988775

2. Sanders DW, Busam M, Hattwick E, et al. Functional outcomes following displaced talar neck fractures. J Orthop Trauma. 2004;18(5):265-270. doi:10.1097/00005131-200405000-00001

3. Sarrafian SK. Anatomy of the foot and ankle: descriptive, topographical, functional. 2nd ed. Philadelphia: JB Lippincott; 1993.

4. Kelly PJ, Sullivan CR. Blood supply of the talus. Clin Orthop Relat Res. 1963;30:37-44.

5. Hawkins LG. Fractures of the neck of the talus. J Bone Joint Surg Am. 1970;52(5):991-1002.

6. Vallier HA, Nork SE, Barei DP, et al. Talar neck fractures: results and outcomes. J Bone Joint Surg Am. 2004;86(8):1616-1624. doi:10.2106/00004623-200408000-00007

7. Coltart WD. Aviator's astragalus. J Bone Joint Surg Br. 1952;34-B(4):545-566. doi:10.1302/0301-620X.34B4.545

8. Anderson HG. The medical and surgical aspects of aviation. London: Oxford Medical Publications; 1919.

9. Dale JD, Ha AS, Chew FS. Update on talar fracture patterns: a large level I trauma center study. AJR Am J Roentgenol. 2013;201(5):1087-1092. doi:10.2214/AJR.12.9918

10. Fortin PT, Balazsy JE. Talus fractures: evaluation and treatment. J Am Acad Orthop Surg. 2001;9(2):114-127. doi:10.5435/00124635-200103000-00005

11. Thordarson DB. Talar body fractures. Orthop Clin North Am. 2001;32(1):65-77. doi:10.1016/s0030-5898(05)70194-7

12. Schulze W, Richter J, Russe O, et al. Surgical treatment of talus fractures: a retrospective analysis of 80 cases. J Orthop Surg Res. 2002;37(3):161-172.

13. Juliano PJ, Nguyen HV, Harris TG, Bosse MJ. Talar neck fractures. Foot Ankle Clin. 2004;9(4):723-736. doi:10.1016/j.fcl.2004.06.004

14. Peterson L, Goldie IF, Lindell D. The arterial supply of the talus. Acta Orthop Scand. 1974;45(2):260-270. doi:10.3109/17453677408989142

15. Lindvall E, Haidukewych G, DiPasquale T, et al. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg Am. 2004;86(10):2229-2234. doi:10.2106/00004623-200410000-00014

16. Valderrabano V, Perren T, Ryf C, et al. Snowboarder's talus fracture: treatment outcome of 20 cases after 3.5 years. Am J Sports Med. 2005;33(6):871-880. doi:10.1177/0363546504272267

17. Higgins TF, Baumgaertner MR. Diagnosis and treatment of fractures of the talus: a comprehensive review of the literature. Foot Ankle Int. 1999;20(9):595-605. doi:10.1177/107110079902000911

18. Lindvall E, Haidukewych G, DiPasquale T, et al. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg Am. 2004;86(10):2229-2234.

19. Daniels TR, Smith JW, Ross TI. Varus malalignment of the talar neck: its effect on the position of the foot and on subtalar motion. J Bone Joint Surg Am. 1996;78(10):1559-1567.

20. Elgafy H, Ebraheim NA, Tile M, et al. Fractures of the talus: experience of two level 1 trauma centers. Foot Ankle Int. 2000;21(12):1023-1029. doi:10.1177/107110070002101206

21. Mulfinger GL, Trueta J. The blood supply of the talus. J Bone Joint Surg Br. 1970;52(1):160-167.

22. Gelberman RH, Mortensen WW. The arterial anatomy of the talus. Foot Ankle. 1983;4(2):64-72. doi:10.1177/107110078300400202

23. 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;60(2):143-156.

24. Tehranzadeh J, Stuffman E, Ross SD. Partial Hawkins sign in fractures of the talus: a report of three cases. AJR Am J Roentgenol. 2003;181(6):1559-1563. doi:10.2214/ajr.181.6.1811559

25. Reach JS Jr, Amrami KK, Felmlee JP, et al. The compartments of the foot: a 3-Tesla magnetic resonance imaging study with clinical correlates for needle pressure monitor insertion. Foot Ankle Int. 2007;28(5):584-589. doi:10.3113/FAI.2007.0584

26. Ebraheim NA, Patil V, Frisch NC, Liu J. Complications of talar neck fractures. Orthop Clin North Am. 2013;44(4):541-546. doi:10.1016/j.ocl.2013.06.007

27. Inaba K, Sharkey PW, Stephen DJ, et al. The increasing incidence of severe pelvic injury in motor vehicle collisions. Injury. 2004;35(8):759-765.

28. Comfort TH, Behrens F, Gaither DW, et al. Long-term results of displaced talar neck fractures. Clin Orthop Relat Res. 1985;(199):81-87.

29. Halvorson JJ, Winter SB, Teasdall RD, Scott AT. Talar neck fractures: a systematic review of the literature. J Foot Ankle Surg. 2013;52(1):56-61. doi:10.1053/j.jfas.2012.10.008

30. Vallier HA. Fractures of the talus: state of the art. J Orthop Trauma. 2015;29(9):385-392. doi:10.1097/BOT.0000000000000378

31. Pajenda G, Vécsei V, Reddy B, Heinz T. Treatment of talar neck fractures: clinical results of 50 patients. J Foot Ankle Surg. 2000;39(6):365-375. doi:10.1016/s1067-2516(00)80065-8

32. Adelaar RS, Madrian JR. Avascular necrosis of the talus. Orthop Clin North Am. 2004;35(3):383-395. doi:10.1016/j.ocl.2004.02.010

33. Lindvall E, Haidukewych G, DiPasquale T, et al. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg Am. 2004;86(10):2229-2234.

34. Dodd A, Lefaivre KA. Outcomes of talar neck fractures: a systematic review and meta-analysis. J Orthop Trauma. 2015;29(5):210-215. doi:10.1097/BOT.0000000000000297

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18. Viva Vault (MRCS/FRCS Oral Examination)

Opening Statement (30 seconds)

"Talus fractures represent 0.3-0.6% of all fractures but carry disproportionate morbidity due to the bone's precarious retrograde blood supply. The most common pattern is a talar neck fracture from forced hyperdorsiflexion. The Hawkins classification stratifies fractures by displacement and dislocation pattern, which directly correlates with avascular necrosis risk ranging from 0-15% in non-displaced fractures to nearly 100% in complete extrusion injuries. Management centres on emergency reduction of dislocations to prevent skin necrosis, followed by anatomical operative fixation to restore articular congruity and maximise the chance of revascularisation."

Expected Viva Questions & Model Answers

Q1: Describe the blood supply to the talus.

A: "The talus receives blood from three extraosseous arterial sources that converge on the tarsal canal and sinus tarsi:

1. Artery of the Tarsal Canal, a branch of the posterior tibial artery, is the dominant vessel supplying up to 50% of the talar body. It enters via the tarsal canal beneath the sustentaculum tali.

2. Deltoid Branch, also from the posterior tibial artery, supplies the medial talar body entering through the deltoid ligament attachment.

3. Artery of the Sinus Tarsi, formed by anastomosis of branches from the dorsalis pedis and peroneal arteries, supplies the talar head and neck.

These vessels form an intraosseous anastomotic network. The critical feature is that blood flow is retrograde—from distal to proximal—meaning fractures through the neck disconnect the body from its arterial inflow. Combined with 60% articular cartilage coverage limiting vascular foramina, this creates high AVN risk when the neck fractures."

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Q2: How would you manage a patient presenting with a displaced talar neck fracture and skin tenting?

A: "This is a surgical emergency requiring immediate reduction to prevent skin necrosis.

Immediate Management:

1. Assessment: Document neurovascular status carefully—pulses, sensation, motor function
2. Analgesia: Adequate pain control
3. Emergency Reduction: Arrange within 6 hours, either ED procedural sedation or theatre GA depending on patient factors and local protocols

Reduction Technique:

• Knee flexed 90° to relax gastrocnemius
• Longitudinal traction on heel
• Maximal plantarflexion to unlock ankle
• Direct pressure on talar body pushing anterolaterally
• Simultaneously dorsiflex and evert foot

Post-Reduction:

• Reassess neurovascular status
• Post-reduction radiographs
• CT scan within 24 hours
• Admission for elevation, observation for compartment syndrome
• Definitive ORIF once soft tissues permit (usually 24-48 hours)

Definitive Surgery:

• Likely anteromedial ± anterolateral approach
• Lag screw fixation ± medial plate if comminution present
• Post-op: Cast NWB for 6-8 weeks minimum

Counselling: High AVN risk (50-100% for Type III-IV fractures); need for long-term surveillance."

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Q3: What surgical approaches do you know for talar neck fixation?

A: "The most common approaches are:

1. Anteromedial Approach (my preferred primary approach):

• Incision medial to tibialis anterior tendon
• Interval between tibialis anterior laterally and neurovascular bundle medially
• Provides access to medial neck and allows medial plate if comminution present
• Must preserve deltoid artery branches for blood supply

2. Anterolateral Approach:

• Incision between extensor digitorum longus and peroneus tertius
• Exposes lateral neck and sinus tarsi
• Useful for clearing bony/soft tissue blocks to reduction
• Visualizes artery of sinus tarsi

3. Combined Approach:

• Often required for complete visualization
• Allows dual screw insertion from optimal angles
• Provides 360-degree fracture site access

Fixation Technique: I would use 2-3 lag screws (3.5mm or 4.0mm). Anterior-to-posterior screws are technically easier, though biomechanically posterior-to-anterior screws provide superior compression. If medial comminution is present, I would add a mini-fragment medial buttress plate to prevent varus collapse."

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Q4: What complications would you counsel the patient about?

A: "I would discuss both early and late complications:

Early Complications:

1. Wound problems: Infection, dehiscence, skin necrosis (5-10%)
2. Neurovascular injury: Nerve damage, vascular injury (less than 5%)
3. Compartment syndrome: Requires emergency fasciotomy (10% in high-energy injuries)

Late Complications:

1. Avascular Necrosis (most important):

   • Risk depends on fracture type (0-15% Type I; 20-50% Type II; 50-100% Type III-IV)
   • Typically manifests 6-24 months post-injury
   • May require salvage fusion or amputation if severe

2. Post-Traumatic Arthritis (40-90%):

   • Subtalar joint most commonly affected
   • May require arthrodesis for pain control

3. Malunion (15-25%):

   • Varus malunion locks subtalar joint
   • May require corrective osteotomy

4. Nonunion (5-10%):

   • Requires revision surgery with bone grafting

5. Chronic Pain and Stiffness (40-60%):

   • Permanent functional limitation
   • May prevent return to high-impact activities

I would emphasize that despite optimal treatment, 40-50% of patients with displaced fractures have long-term limitations, and subsequent surgery is common."

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Summary for Rapid Revision

Key Facts:

• 0.3-0.6% of all fractures; 2nd most common tarsal fracture
• 60% cartilage coverage; retrograde blood supply → high AVN risk
• Hawkins classification: I (0-15%), II (20-50%), III (50-100%), IV (~100% AVN)
• Emergency reduction within 6 hours for dislocation (skin threat)
• Canale view: 15° pronation + 75° cephalad beam
• Hawkins sign at 6-8 weeks: subchondral lucency = good prognosis
• Operative: less than 2mm displacement threshold; lag screws ± medial plate
• Complications: AVN (most common), arthritis (40-90%), varus malunion (15-25%)

Must-Know Surgical Details:

• Anteromedial approach (primary)
• 2-3 lag screws (3.5-4.0mm)
• Medial plate for medial comminution
• NWB 6-8 weeks minimum

Viva One-Liner: "Talar neck fractures are high-energy injuries with AVN risk stratified by Hawkins classification; management requires emergency reduction if dislocated, anatomical operative fixation for displacement > 2mm, and long-term surveillance for AVN and arthritis."

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(End of Enhanced Topic)