Orthopaedic Surgery - Sternoclavicular Joint Dislocation

Basics

Sternoclavicular joint dislocation occurs when the:

Medial end of the clavicle

loses its normal articulation with the:

Sternum.

The dislocation may be:

Anterior

or

Posterior.

Clinical Importance

Anterior dislocations are more common and often remain somewhat:

Unstable or prominent

even after reduction.

Despite this, they usually produce relatively little long-term:

Functional impairment.

Posterior dislocations are much more dangerous because the displaced clavicle may compress or injure:

Mediastinal structures.

Posterior Dislocation

A posterior sternoclavicular dislocation may compromise:

Major blood vessels

Trachea

Esophagus

or nearby:

Nerves.

For this reason, posterior dislocation generally requires:

Urgent reduction.

Epidemiology

Sternoclavicular dislocation is:

Rare.

It accounts for approximately:

1% of all joint dislocations

and about:

3% of shoulder-girdle injuries.

Mechanism Distribution

Historical series have attributed approximately:

40%

to:

Motor vehicle trauma

and approximately:

21%

to:

Sports-related injuries.

Direction

Approximately:

63%

of sternoclavicular dislocations are:

Anterior.

Anatomy and Pathophysiology

The sternoclavicular joint is a:

Diarthrodial joint

between the medial clavicle and the:

Manubrium.

Ligamentous Stability

The principal restraints to anterior-posterior translation are the:

Anterior and posterior sternoclavicular capsular ligaments.

Additional support is provided by the:

Costoclavicular ligament

and

Intra-articular disc ligament.

Structures Posterior to the Joint

Several critical structures lie immediately behind the:

Sternoclavicular joint.

These include the:

Brachiocephalic vessels

Trachea

Esophagus

Vagus nerve

Phrenic nerve

and other:

Mediastinal vascular structures.

Importance of Posterior Displacement

Posterior displacement of the medial clavicle can produce:

Compression

Laceration

or

Obstruction

of these structures.

This explains why posterior dislocation is considered a potentially:

Life-threatening injury.

Medial Clavicular Physis

The medial clavicular growth plate is the last major physis in the body to:

Fuse.

Closure commonly occurs around:

23–25 years of age.

Physeal Injury in Young Patients

In patients younger than approximately:

25 years

an apparent sternoclavicular dislocation may actually represent a:

Medial clavicular physeal fracture-dislocation.

These injuries can mimic a true:

SC joint dislocation.

Prognosis of Physeal Injury

Medial clavicular physeal fractures generally have a better healing potential than true:

Sternoclavicular dislocations.

Etiology

The injury usually follows:

High-energy trauma

such as:

Motor vehicle collision

or

Contact sports.

Direct Mechanism

A direct blow to the:

Medial clavicle

typically drives it:

Posteriorly.

Indirect Mechanism

A force applied laterally across the shoulder girdle may produce sternoclavicular dislocation through:

Compression of the shoulder.

Examples include:

Football pileups

and

Side-impact motor vehicle collisions.

Associated Injuries

Because these injuries often occur after:

High-energy trauma

patients should be evaluated for additional:

Thoracic

Spinal

and

Extremity injuries.

Trauma Assessment

A complete trauma assessment using standard:

ATLS principles

is appropriate when the mechanism is substantial.

Diagnosis

Diagnosis depends on:

Mechanism

Physical examination

and especially:

CT imaging.

Signs and Symptoms

Patients usually report:

Severe pain around the sternoclavicular joint

that worsens with:

Arm movement.

Shoulder Compression

Pain may increase when the shoulders are:

Compressed toward each other.

Arm Support

Patients frequently support the injured arm using the:

Opposite hand

to reduce:

Shoulder movement and pain.

History

Important questions include the presence of:

Upper-extremity numbness

Weakness

Shortness of breath

Voice change

Difficulty speaking

or

Difficulty swallowing.

These symptoms raise concern for:

Posterior displacement.

Respiratory Symptoms

Dyspnea, stridor, or difficulty speaking may indicate compression of the:

Trachea

or other mediastinal structures.

Swallowing Difficulty

Dysphagia may result from compression of the:

Esophagus.

Neurologic Symptoms

Arm weakness, numbness, or paresthesia may indicate involvement of the:

Brachial plexus

or nearby neurovascular structures.

Physical Examination

The examination should include:

Inspection

Palpation

Neurovascular assessment

and evaluation for:

Thoracic compromise.

Anterior Dislocation

In an anterior dislocation, the medial clavicle is typically:

Prominent and palpable

compared with the opposite side.

Posterior Dislocation

In posterior dislocation, the medial clavicle may be:

Difficult to palpate

and there may be a:

Visible or palpable depression

over the sternoclavicular joint.

Shoulder Position

The affected shoulder may appear:

Shortened

and displaced:

Forward.

Neurologic Examination

A careful neurologic examination of both upper extremities should assess:

Motor function

Sensation

and possible:

Brachial plexus involvement.

Vascular Examination

Compare:

Radial pulses

between both arms.

Also evaluate:

Capillary refill

and overall:

Limb perfusion.

Venous Congestion

Look for:

Neck swelling

Upper-extremity swelling

or visible venous distention.

These may indicate obstruction of:

Central venous structures.

Imaging

Plain Radiographs

The sternoclavicular joint is difficult to evaluate accurately on:

Routine radiographs.

A chest radiograph may suggest asymmetry but is often:

Nondiagnostic.

Specialized Views

Specialized sternoclavicular projections have historically been used, but they can be:

Technically difficult

and difficult to:

Interpret.

CT

CT is the:

Imaging study of choice

when sternoclavicular dislocation is suspected.

CT Advantages

CT demonstrates:

Direction of displacement

Associated fractures

and the relationship of the medial clavicle to:

Mediastinal structures.

Posterior Dislocation

In posterior dislocation, CT can show whether the clavicle is compressing:

Great vessels

Trachea

or

Esophagus.

CT Angiography

When posterior displacement or vascular injury is suspected, consider:

CT angiography.

This can define the relationship between the clavicle and:

Major thoracic vessels.

Differential Diagnosis

Important alternatives include:

Sternoclavicular sprain

Medial clavicular physeal fracture

and other forms of:

Thoracic trauma.

Sternoclavicular Sprain

A sprain may cause pain and tenderness without true:

Dislocation.

These injuries are typically treated:

Symptomatically.

Pneumothorax and Thoracic Injury

Shortness of breath may be caused by associated:

Pneumothorax

Hemothorax

or other thoracic injury rather than the sternoclavicular dislocation itself.

A complete trauma assessment is therefore essential.

Treatment

Initial Stabilization

Posterior sternoclavicular dislocations require:

Urgent reduction.

Anterior dislocations are also commonly reduced, although they frequently become:

Recurrently prominent.

Posterior Dislocation

Because of the risk of injury to mediastinal structures, posterior dislocation should generally be reduced in a:

Controlled operative environment.

Analgesia and Sedation

Closed reduction often requires:

Deep sedation

or

General anesthesia

because of:

Pain

and

Muscle spasm.

Anterior Dislocation Reduction

The patient is positioned:

Supine

with a firm bolster approximately:

3–4 inches

thick between the:

Scapulae.

Positioning

The affected shoulder is typically placed in approximately:

90° of abduction

and about:

15° of extension.

Traction

An assistant applies:

Longitudinal traction

to the affected arm.

Direct Pressure

Posteriorly directed pressure is then applied to the:

Prominent medial clavicle

to guide it back into:

Alignment.

Postreduction Immobilization

After reduction, the arm may be placed in a:

Sling and swathe

or

Figure-8 dressing.

Posterior Dislocation Reduction

Posterior reduction should be undertaken with:

Thoracic or cardiothoracic surgical backup

because releasing the clavicle may unmask injury to:

Great vessels

or

Lung structures.

Operative Environment

Reduction is usually performed in the:

Operating room

with:

Sterile preparation

and appropriate emergency resources available.

Abduction-Traction Technique

One closed technique involves:

Abducting and extending the arm

and applying:

Longitudinal traction.

Shoulder Pressure

Downward pressure may be applied over the:

Glenohumeral joint

while the medial clavicle is pulled:

Anteriorly.

Direct Clavicular Manipulation

The medial clavicle may be grasped with the:

Fingers

and drawn anteriorly.

If this fails, a sterile:

Towel clamp

may sometimes be used in a controlled operative setting.

Reduction Sign

Successful reduction may produce an audible or palpable:

Pop.

Adduction-Traction Technique

Another technique uses the arm in:

Adduction

with:

Lateral traction.

Pressure is applied over the shoulder while the medial clavicle is guided:

Anteriorly.

Immobilization After Posterior Reduction

After successful reduction, the arm is placed in a:

Sling and swathe

or

Figure-8 dressing.

Activity

After reduction, the affected arm is generally immobilized for approximately:

4–6 weeks.

Sleeping Position

Patients may be more comfortable sleeping:

Upright

or in a:

Recliner

during the early period.

Nursing and Acute Care

Patients should have:

Intravenous access

and appropriate:

Analgesia.

Before definitive reduction, they may be more comfortable sitting:

Upright

with the arm supported in a:

Sling.

Physical Therapy

During immobilization, exercises for the:

Hand

Wrist

and

Elbow

can begin immediately.

Shoulder Motion

Shoulder range-of-motion exercises are usually delayed until approximately:

4–6 weeks

depending on stability and:

Pain.

Medication

Analgesic treatment may include:

Acetaminophen

NSAIDs

and, in the acute setting,

Short-term opioid medication.

Surgery

Surgery is indicated when a posterior dislocation cannot be:

Reduced closed

or remains:

Unstable.

Open Reduction

Failed closed reduction requires:

Open reduction

in the:

Operating room.

Thoracic Surgical Backup

A thoracic or cardiothoracic surgeon should be available because major vessel or lung injury may be:

Unmasked during reduction.

Stability Assessment

After open reduction, the sternoclavicular joint is assessed for:

Residual instability.

Many posterior dislocations become stable once:

Reduced.

Reconstruction

Persistently unstable joints may require:

Soft-tissue reconstruction

using:

Sutures

or

Tendon grafts.

Hardware Contraindication

Fixation with:

Kirschner wires

or

Steinmann pins

is contraindicated.

These implants can migrate into the:

Mediastinum

and cause catastrophic:

Cardiac or vascular injury.

Delayed Posterior Dislocation

Posterior dislocations untreated for more than approximately:

7–10 days

may become difficult to reduce closed because of:

Retrosternal adhesions and scarring.

Open reduction is more likely to be required.

Chronic Anterior Instability

Persistent anterior subluxation or dislocation is often treated:

Nonoperatively.

Functional Effect of Anterior Instability

Although the prominence may be visible, most patients have:

Minimal functional impairment.

Symptomatic Anterior Instability

Surgery may be considered when there is persistent:

Pain

Recurrent instability

or substantial:

Functional limitation.

Treatment generally involves:

Open reduction and stabilization.

Follow-Up

All patients with sternoclavicular dislocation should have follow-up with an:

Orthopaedic surgeon.

Immobilization

For a stable reduction, immobilization is commonly continued for:

4–6 weeks.

Range of Motion

Gentle shoulder range-of-motion exercises may usually begin after approximately:

4–6 weeks.

Unstable Anterior Dislocation

When persistent anterior instability is treated nonoperatively, the sling can be continued until:

Pain decreases.

Prognosis

Posterior dislocations are generally:

Stable after successful reduction.

Anterior Dislocations

Anterior dislocations are more likely to remain:

Unstable

or visibly:

Prominent.

Despite this, they usually cause relatively little:

Functional disability.

Cosmetic Deformity

Chronic anterior instability may leave a persistent:

Prominence over the medial clavicle.

This is primarily a:

Cosmetic issue

for many patients.

Complications

The most serious complications occur with:

Posterior dislocations.

Great-Vessel Injury

The medial clavicle may compress or lacerate:

Brachiocephalic vessels

or other major:

Thoracic vessels.

This can lead to:

Life-threatening hemorrhage.

Tracheal Compression

Posterior displacement may compress the:

Trachea

and produce:

Respiratory distress.

Esophageal Compression

Compression of the esophagus can cause:

Dysphagia.

Brachial Plexopathy

Posterior displacement may injure the:

Brachial plexus

producing:

Weakness

Numbness

or

Paresthesia.

Thoracic Outlet Syndrome

Chronic compression may rarely contribute to:

Thoracic outlet syndrome.

Anterior Dislocation Complications

Anterior dislocations are generally more benign but may produce:

Cosmetic deformity

Degenerative joint changes

Recurrent instability

and

Activity-related pain.

Patient Monitoring

Follow-up should continue until:

Pain has resolved

Range of motion is restored

and

Normal or near-normal function returns.

Key Principle

Sternoclavicular joint dislocation is displacement of the medial clavicle from the sternum and may be anterior or posterior.

Anterior dislocations are more common and often remain:

Prominent or unstable, but usually cause relatively little functional impairment.

Posterior dislocations are potentially:

Life-threatening because the displaced clavicle may compress or injure the:

Great vessels, trachea, esophagus, or brachial plexus.

CT is the:

Imaging study of choice, with CT angiography considered when posterior displacement threatens vascular structures.

Posterior dislocations require:

Urgent reduction in a controlled setting with thoracic surgical backup, while chronic anterior instability is often treated:

Nonoperatively unless symptoms are substantial.