Orthopaedic Surgery - Talus Fracture

Basics

The talus is a critical bone of the:

Hindfoot

that transmits body weight from the tibia to the:

Foot.

It articulates with the:

Tibia

Fibula

Calcaneus

and

Navicular.

Functional Importance

The talus plays an essential role in:

Ankle motion

Subtalar motion

and distribution of:

Weight-bearing forces.

Because of its importance to both the ankle and hindfoot, even relatively small abnormalities in talar alignment may substantially affect:

Foot function.

Articular Cartilage

Approximately:

60% of the talar surface

is covered with:

Articular cartilage.

This leaves relatively little surface area available for entry of:

Blood vessels.

Blood Supply

The talar blood supply enters through a limited number of:

Soft-tissue attachments

particularly around the:

Talar neck.

As a result, displaced fractures can interrupt vascular inflow and predispose the talus to:

Osteonecrosis.

Clinical Importance

Talus fractures can be difficult to:

Diagnose

and may have serious complications even when treated appropriately.

A high index of suspicion is important because delayed diagnosis can increase the risk of:

Malunion

Arthritis

and

Osteonecrosis.

Anatomical Types

Fractures may involve the:

Talar neck

Talar body

Posterior process

or

Lateral process.

Osteochondral injuries of the talar dome represent another important group of:

Talar injuries.

Talar Neck Classification

Talar neck fractures are commonly classified using the:

Modified Hawkins classification.

Hawkins Type I

Type I is a:

Nondisplaced talar neck fracture

with preserved alignment of the:

Subtalar

and

Tibiotalar joints.

Hawkins Type II

Type II consists of a displaced talar neck fracture with:

Subluxation or dislocation of the subtalar joint

while the:

Tibiotalar joint remains reduced.

Hawkins Type III

Type III involves a displaced talar neck fracture with dislocation of both the:

Subtalar joint

and

Tibiotalar joint.

This pattern carries a substantially greater risk of:

Osteonecrosis.

Hawkins Type IV

Type IV represents the most severe pattern, with displacement involving the talus and disruption of additional:

Peritalar articulations, classically including the talonavicular joint.

Severe cases may approach:

Talar extrusion.

Talar Body Fractures

Talar body fractures may be described according to the orientation of the:

Fracture plane.

Type I Talar Body Fracture

Type I fractures are primarily:

Coronal

or

Sagittal.

Type II Talar Body Fracture

Type II fractures are primarily:

Horizontal.

Talar Process Fractures

Process fractures include:

Posterior process fractures

and

Lateral process fractures.

Pediatric Considerations

Children have a relatively greater:

Cartilage-to-bone ratio

than adults.

The pediatric talus is therefore somewhat more capable of:

Deformation

before developing a complete:

Fracture.

Epidemiology

Talus fractures are:

Uncommon.

There is no strong universal association with:

Age

or

Sex.

Incidence

Talus fractures account for approximately:

3% of foot fractures.

About:

Half

involve the:

Talar neck.

Talar Body Fractures

Talar body fractures are less common.

Historical reports have estimated that they account for approximately:

7–38% of tarsal fractures

depending on the definition and study population.

Risk Factors

Important mechanisms and activities associated with talus fracture include:

Motor vehicle collisions

Falls from height

and

Snowboarding.

Pathophysiology

The fracture pattern depends on the:

Direction and magnitude of force.

Talar Neck Mechanism

Talar neck fractures commonly occur when the foot is forced into:

Extreme dorsiflexion.

The talar neck becomes impacted against the:

Anterior distal tibia

and may fracture.

Lateral Process Fracture

Lateral process fractures are particularly associated with:

Snowboarding.

A common mechanism is:

External rotation

applied to a:

Dorsiflexed foot

inside a rigid:

Boot.

Talar Body Fracture

Talar body fractures typically result from:

Axial compression

of the talus between the:

Tibia

and

Calcaneus.

Etiology

Most major talus fractures result from:

High-energy trauma.

The classic mechanism includes forceful:

Dorsiflexion of the forefoot and ankle

often combined with:

Axial loading.

Associated Conditions

Talar neck fractures may occur with:

Medial malleolus fractures

and other injuries involving the:

Ankle

Calcaneus

or

Midfoot.

High-Energy Trauma

Because many talar fractures follow high-energy mechanisms, the patient should also be evaluated for additional:

Lower-extremity

Pelvic

Spinal

or systemic:

Traumatic injuries.

Diagnosis

Diagnosis requires:

Careful examination

and appropriate:

Imaging.

Some talar fractures, particularly small process fractures, are easily:

Missed.

Signs and Symptoms

Typical symptoms include:

Severe ankle or hindfoot pain

after substantial:

Trauma.

Swelling

Marked:

Swelling

may develop around the:

Ankle and hindfoot.

Ecchymosis

Bruising may occur over the:

Ankle

Hindfoot

or

Midfoot.

Deformity

Displaced fractures may produce visible:

Deformity

or abnormal prominence of:

Talar fragments.

History

Common injury mechanisms include:

Motor vehicle collision

and

Fall from height.

Aviator’s Astragalus

Historically, talar neck fractures were associated with pilots who sustained violent dorsiflexion injuries while bracing their feet against:

Aircraft rudder pedals.

This led to the historic term:

Aviator’s astragalus.

Physical Examination

Examine the:

Ankle

and

Hindfoot

carefully.

Tenderness

Assess for:

Focal talar tenderness

including around the:

Talar neck

Lateral process

and

Posterior process.

Deformity

Look for:

Abnormal contour

Skin tenting

or displacement suggesting:

Dislocation or fracture-dislocation.

Motion

Assess ankle and subtalar motion carefully when safe.

Pain with:

Ankle

or

Subtalar movement

may indicate significant:

Talar injury.

Skin Examination

Because there is very little protective soft tissue around portions of the talus, displaced fragments may threaten:

Skin viability.

Look for:

Tenting

Blanching

Open wounds

or impending:

Skin necrosis.

Neurovascular Examination

Document:

Sensation

Motor function

Pulses

and

Capillary refill.

Missed Process Fractures

Lateral and posterior process fractures are frequently mistaken for:

Ankle sprains.

Persistent focal pain after an apparently routine ankle injury should lower the threshold for:

CT imaging.

Imaging

Plain Radiographs

Initial imaging usually includes:

AP and lateral ankle radiographs

and appropriate:

Foot views.

Talar Neck View

A specialized oblique view of the talar neck may improve visualization.

This is commonly obtained with the foot in:

Plantarflexion

and approximately:

15° of pronation.

This is often referred to as the:

Canale view.

CT

CT is extremely useful for determining:

Fracture displacement

Comminution

Articular involvement

and presence of:

Associated fractures.

Role of CT

CT is particularly valuable for:

Talar neck

Talar body

and

Process fractures

that are incompletely defined on:

Plain radiographs.

MRI

MRI is not usually the first study for an acute displaced fracture.

It is more useful later when evaluating:

Osteonecrosis

or occult injury when radiographs and CT are:

Nondiagnostic.

Pathological Findings

Occasionally a talar fracture occurs through:

Abnormal bone.

Possible underlying lesions include:

Bone cysts

or

Bone tumors.

Differential Diagnosis

Important differential diagnoses include:

Ankle fracture

Ankle dislocation

Talar dislocation

Calcaneus fracture

and

Navicular fracture.

Treatment

Treatment depends on:

Fracture location

Displacement

Joint congruity

Soft-tissue condition

and

Vascular risk.

Initial Stabilization

Initial treatment includes:

Immobilization

Elevation

and

Cold therapy

for swelling and pain.

Urgent Reduction

A displaced talar fracture or fracture-dislocation with threatened skin should undergo:

Urgent reduction.

The immediate priority is restoration of:

Alignment

and relief of pressure on:

Skin and neurovascular structures.

Importance of Early Reduction

Prompt reduction decreases the risk of:

Skin necrosis

Soft-tissue compromise

and secondary:

Infection.

Nondisplaced Fractures

Selected nondisplaced fractures may be treated with:

Cast or boot immobilization

and strict:

Non-weight-bearing.

Historical Immobilization

Traditional treatment of nondisplaced talar neck fractures may involve below-knee immobilization for up to approximately:

12 weeks

with at least:

6 weeks of non-weight-bearing.

Duration should be individualized according to:

Radiographic healing.

Hawkins Type II

Type II talar neck fractures require:

Anatomic reduction.

Reduction may be achieved by:

Closed

or

Open methods.

Hawkins Type III

Type III injuries almost always require:

Operative reduction and fixation

because of substantial:

Displacement and instability.

Talar Body Fractures

Displaced talar body fractures usually require:

Operative fixation

to restore:

Articular congruity.

Osteonecrosis Risk

Talar body fractures have a particularly high risk of:

Posttraumatic osteonecrosis

and

Posttraumatic arthritis.

Irreducible Fracture

A displaced fracture that cannot be reduced closed requires:

Open reduction and internal fixation.

Soft-Tissue Risk

Displaced talar fragments may create severe pressure against the thin overlying:

Skin.

This can cause:

Skin necrosis

and subsequent:

Infection.

Process Fractures

Small minimally displaced process fractures may often be treated:

Nonoperatively.

Small Process Fracture

A talar process fracture measuring less than approximately:

1 cm

and displaced less than:

2 mm

may be treated with:

Non-weight-bearing immobilization

for approximately:

6 weeks.

Larger Process Fracture

Larger or more displaced fragments may require:

Open reduction and internal fixation

or, in selected small symptomatic fragments,

Excision.

Pediatric Treatment

Nondisplaced pediatric fractures may be treated with:

Immobilization

for approximately:

6–8 weeks.

Acceptable Pediatric Alignment

Because children have greater remodeling capacity, small residual deformity may be acceptable.

Historical thresholds include less than approximately:

5 mm of displacement

and

5° of angulation

after reduction.

Activity

Patients are generally kept:

Non-weight-bearing

for at least:

4–6 weeks

and often longer depending on:

Fracture severity and healing.

Physical Therapy

Range-of-motion exercises are typically started after adequate fracture:

Stability

and removal of:

Immobilization.

Rehabilitation Goals

Therapy focuses on restoring:

Ankle motion

Subtalar motion

Strength

and

Gait.

Medication

Acute pain may initially require:

Short-term opioid analgesia.

As symptoms improve, treatment can transition to:

Acetaminophen

or

NSAIDs

when medically appropriate.

Surgery

The principal surgical goal is:

Anatomic reduction of the articular surfaces

with stable:

Internal fixation.

Surgical Approaches

Talar neck fractures may be approached through:

Medial

and

Lateral incisions.

Dual-Incision Technique

Displaced fractures often benefit from:

Combined anteromedial and anterolateral approaches

because visualization from both sides improves:

Reduction accuracy.

Fluoroscopy

Reduction and implant placement are confirmed with:

Intraoperative fluoroscopy.

Screw Fixation

Cannulated screws may be placed in:

Antegrade

or

Retrograde orientation

depending on fracture geometry.

Plate Fixation

Comminuted talar neck fractures may not provide adequate purchase for screws alone.

In these cases:

Low-profile plate fixation

may help maintain:

Length

Alignment

and

Rotation.

Talar Body Exposure

Talar body fractures can be more difficult to expose because of the surrounding:

Articular surfaces

and

Malleoli.

Medial Malleolar Osteotomy

A:

Medial malleolar osteotomy

may be required to obtain adequate visualization of selected:

Talar body fractures.

Articular Screw Placement

When screws pass through an articular surface, the heads should be:

Countersunk

to avoid damage to opposing:

Cartilage.

Process Fracture Fixation

Large or displaced process fractures may be stabilized using:

Small screws

or

Kirschner wires.

Compartment Syndrome

Severe hindfoot injuries may be associated with:

Foot compartment syndrome.

Monitoring for Compartment Syndrome

Watch for:

Progressive pain

Tense swelling

Pain with passive toe motion

and neurologic:

Changes.

Pressure Measurement

If the diagnosis remains uncertain, intracompartmental pressures may be:

Measured.

Fasciotomy

Confirmed compartment syndrome requires urgent:

Fasciotomy.

Postoperative Immobilization

After fixation, the extremity is placed in a:

Well-padded splint

until swelling decreases.

It may then be converted to a:

Below-knee cast or boot.

Weight Bearing After Surgery

Weight bearing is generally restricted until there is sufficient:

Fracture healing

and stability.

The duration varies according to:

Fracture pattern

Fixation

and evidence of:

Osteonecrosis.

Follow-Up

Long-term radiographic follow-up is important.

Duration

Nondisplaced fractures may be followed radiographically for at least:

18–24 months.

Displaced fractures and fractures complicated by:

Osteonecrosis

may require even longer:

Surveillance.

Prognosis

Outcome is strongly related to the:

Severity of the original injury.

Even with accurate reduction and fixation, severe initial disruption can lead to:

Osteonecrosis

and

Arthritis.

Talar Body Prognosis

Talar body fractures generally have a:

Less favorable prognosis

because of extensive:

Articular injury

and

Vascular disruption.

Historical Outcomes

Some historical series report that as many as:

88%

of patients with talar body fractures developed:

Osteonecrosis

Posttraumatic arthritis

or both.

Complications

Major complications include:

Foot compartment syndrome

Osteonecrosis

Skin necrosis

Infection

Delayed union

Nonunion

Malunion

and

Posttraumatic arthritis.

Osteonecrosis

Osteonecrosis is one of the most feared complications because the talus has a relatively:

Tenuous vascular supply.

Risk increases with:

Fracture displacement

Dislocation

and greater:

Soft-tissue disruption.

Delayed Union

Delayed healing is relatively common because of the limited:

Blood supply

and high proportion of:

Articular cartilage.

Nonunion

Nonunion may cause:

Persistent pain

and chronic:

Disability.

Treatment may require:

Revision fixation

Bone grafting

or

Fusion.

Malunion

Malunion alters normal:

Hindfoot mechanics

and redistributes force across the:

Ankle and subtalar joints.

This may result in:

Chronic pain

and progressive:

Arthritis.

Posttraumatic Arthritis

Arthritis may develop in the:

Tibiotalar

Subtalar

or

Talonavicular joints.

It may occur with or without:

Osteonecrosis.

Salvage Procedures

Severe symptomatic arthritis or talar collapse may ultimately require:

Subtalar fusion

Tibiotalar fusion

or

Pantalar fusion.

Patient Monitoring

Follow-up should assess:

Fracture union

Alignment

Joint congruity

and evidence of:

Talar vascularity.

Hawkins Sign

The:

Hawkins sign

is a subchondral radiolucent band that may appear in the:

Talar dome

during follow-up.

Meaning of Hawkins Sign

It represents:

Subchondral bone resorption

and therefore indicates that at least some:

Talar blood supply is preserved.

Clinical Significance

The presence of a Hawkins sign is reassuring and makes:

Osteonecrosis less likely.

Its absence, however, does not by itself prove:

Osteonecrosis.

MRI for Osteonecrosis

MRI can help confirm or further assess suspected:

Talar osteonecrosis

when radiographic findings are:

Uncertain.

Key Principle

Talus fractures are uncommon but potentially severe hindfoot injuries because much of the talus is covered by articular cartilage and its vascular supply is relatively vulnerable.

Fractures may involve the:

Neck, body, lateral process, or posterior process, with talar neck injuries commonly classified by the:

Modified Hawkins system.

Displaced fractures require:

Urgent reduction to protect the skin, soft tissues, joints, and remaining vascular supply, followed by stable fixation when indicated.

CT is particularly valuable for defining:

Displacement, comminution, and articular involvement.

The most important long-term complications are:

Osteonecrosis, posttraumatic arthritis, malunion, nonunion, and hindfoot stiffness.

Long-term radiographic surveillance is essential, with the:

Hawkins sign serving as a reassuring indicator of preserved talar vascularity when present.