Orthopaedic Surgery - Scaphoid Fracture

Basics

A scaphoid fracture is a fracture of the:

Scaphoid bone

which is the most radial carpal bone on the:

Thumb side of the wrist.

It most commonly results from:

Hyperextension of the wrist

after a fall onto an outstretched hand.

Clinical Importance

Scaphoid fractures are important because they may be:

Missed on initial radiographs

and are at risk for:

Delayed union

Nonunion

Avascular necrosis

and ultimately:

Post-traumatic wrist arthritis.

Synonym

The scaphoid was historically referred to as the:

Carpal navicular.

Therefore, older literature may use the term:

Navicular fracture.

Classification

Scaphoid fractures can be classified in several ways.

By Anatomy

Fractures may involve the:

Proximal pole

Waist

or

Distal pole.

The:

Waist

is the most common fracture location.

By Displacement

Fractures may be:

Nondisplaced

or

Displaced.

Displacement increases the risk of:

Nonunion

and

Carpal instability.

By Direction

The fracture line may be:

Transverse

or

Oblique.

Vertically oriented or unstable fracture patterns generally carry a greater risk of:

Mechanical instability.

By Chronology

Fractures may be described as:

Acute

or

Chronic.

Chronic injuries may present as:

Delayed union

Nonunion

or established:

Scaphoid nonunion advanced collapse.

Herbert Classification

The Herbert classification categorizes scaphoid injuries according to:

Stability

Fracture pattern

Location

and

Healing status.

Broadly, fractures are considered:

Stable

or

Unstable.

Mechanism-Based Classification

Scaphoid fractures may occur after:

Low-energy trauma, such as a simple fall

or

High-energy trauma, such as a motor vehicle collision.

They may also occur as:

Isolated fractures

or as part of more complex injuries involving:

Ligament disruption

Carpal dislocation

or other fractures.

Prevention

Preventive measures include:

Wrist guards or protective equipment

during high-risk activities such as:

Rollerblading

Skateboarding

and certain contact or high-impact sports.

Epidemiology

The scaphoid is the:

Most commonly fractured carpal bone.

It accounts for more than:

Two-thirds of carpal fractures

in many series.

Incidence

Reported incidence ranges approximately from:

8–43 fractures per 100,000 persons per year.

Age and Sex

Scaphoid fractures occur most frequently in:

Young adults

and are more common in:

Men

than women.

They are particularly frequent among:

Athletes

Military personnel

and individuals exposed to high-energy trauma.

Typical Circumstances

Common mechanisms include:

Falls

Sports injuries

Motor vehicle collisions.

Risk Factors

Risk factors for sustaining the fracture include participation in:

Contact sports

and activities with a high risk of falling onto the hand.

Risk Factors for Nonunion

Factors associated with increased risk of nonunion include:

Proximal pole fracture

Significant displacement

High-energy trauma

Vertical or distal-oblique fracture configuration

Delayed diagnosis

Delayed treatment

Blood Supply

The blood supply of the scaphoid is clinically crucial.

Most arterial supply enters the scaphoid through vessels arising near the:

Distal portion of the bone

and then travels:

Retrograde toward the proximal pole.

Proximal Pole Vascularity

Because much of the blood supply reaches the proximal pole from distal entry points, a fracture through the:

Waist

or

Proximal scaphoid

can interrupt this circulation.

This places the proximal fragment at increased risk for:

Avascular necrosis.

Pathophysiology

The scaphoid serves as a mechanical bridge between the:

Proximal carpal row

and

Distal carpal row.

This bridging position exposes it to substantial bending and shear forces during wrist loading.

Etiology

The classic mechanism is:

Axial loading through an outstretched hand

with the wrist in:

Extension

often combined with:

Radial or ulnar deviation

and forearm pronation.

A direct blow to the wrist may also cause fracture.

Diagnosis

Diagnosis requires a high index of suspicion because some fractures are:

Radiographically occult at presentation.

A patient with typical symptoms and examination findings should be treated as having a scaphoid fracture until the diagnosis is reasonably excluded.

Signs and Symptoms

Typical symptoms include:

Radial-sided wrist pain

Pain with wrist movement

Weakness

and occasionally:

Clicking.

History

Ask about:

Fall onto an outstretched hand

Direct wrist trauma

Sports injury

Motor vehicle trauma

Persistent wrist pain after a prior injury.

Delayed Presentation

Some patients present:

Weeks, months, or even years later

with:

Persistent aching

Weak grip

Clicking

or progressive loss of wrist function.

Delayed presentation should raise concern for:

Nonunion

or

Post-traumatic arthritis.

Physical Examination

Wrist Motion

Pain is commonly reproduced by:

Wrist flexion

Extension

and

Radial deviation.

Swelling

Swelling may be:

Minimal or absent

because a nondisplaced scaphoid fracture may produce little visible hemorrhage.

Anatomic Snuffbox Tenderness

Tenderness in the:

Anatomic snuffbox

is a classic finding.

The snuffbox lies between the:

Extensor pollicis longus

and

Extensor pollicis brevis/abductor pollicis longus tendons.

Clinical Significance

When marked snuffbox tenderness is present after an appropriate mechanism:

Scaphoid fracture should be presumed until excluded.

Scaphoid Tubercle Tenderness

Palpation over the:

Volar scaphoid tubercle

may also reproduce pain.

This is another useful finding when a fracture is suspected.

Axial Thumb Compression

Applying longitudinal compression through the:

First metacarpal

may produce pain over the scaphoid.

This supports the diagnosis but is not sufficiently specific to be used alone.

Neurovascular Examination

A complete examination should document:

Motor function

Sensation

Distal perfusion

especially after high-energy injury.

Laboratory Tests

No laboratory test is routinely useful for diagnosing an acute scaphoid fracture.

Imaging

Plain Radiographs

Initial radiographs should include:

PA view

Lateral view

45° pronated oblique view

and a:

PA view with ulnar deviation

commonly referred to as a:

Scaphoid view.

Associated Carpal Injury

Radiographs should also be examined carefully for signs of:

Carpal instability

Perilunate injury

Ligament disruption

Associated fracture.

Occult Fracture

Initial plain radiographs may be:

Normal

despite the presence of a true nondisplaced scaphoid fracture.

Therefore, normal radiographs do not exclude the diagnosis when:

Clinical suspicion remains high.

MRI

MRI is highly sensitive for:

Occult scaphoid fracture

and can also assess:

Bone marrow edema

Associated ligament injury

and, in chronic cases,

Vascularity of the proximal pole.

CT

CT provides excellent assessment of:

Fracture displacement

Angulation

Comminution

Union

and

Carpal alignment.

It is especially useful for:

Preoperative planning

and evaluation of:

Healing.

MRI Versus CT

MRI is particularly useful for:

Early occult fracture detection.

CT is generally superior for defining:

Fracture geometry

and assessing:

Bony union.

Differential Diagnosis

Important alternatives include:

Wrist sprain

Scapholunate ligament injury

Perilunate dislocation

Distal radius fracture

Carpal instability

Other carpal fracture.

Treatment

General Principles

Management depends on:

Fracture location

Displacement

Stability

Chronicity

Patient activity level

and presence of:

Associated injuries.

Suspected Fracture With Normal Radiographs

If clinical suspicion remains high despite normal initial radiographs, the wrist should be:

Immobilized in a thumb-spica splint

or otherwise protected while further evaluation is arranged.

Traditional Reassessment

Historically, patients were immobilized for approximately:

10–14 days

and then re-examined with repeat radiographs.

At that time, fracture lines may become more visible because of:

Early bone resorption at the fracture margins.

Modern Imaging Strategy

Where readily available, early:

MRI

or

CT

may avoid unnecessary prolonged immobilization and establish the diagnosis sooner.

Nondisplaced Fractures

Nondisplaced and many minimally displaced fractures can be treated with:

Cast or splint immobilization.

Distal Pole Fractures

Most nondisplaced distal pole fractures heal reliably with approximately:

6–8 weeks of immobilization.

Waist Fractures

Nondisplaced waist fractures commonly require:

Longer immobilization

sometimes up to approximately:

8–12 weeks

depending on healing.

Type of Cast

The ideal immobilization method remains debated.

Options include:

Short-arm thumb-spica cast

Long-arm thumb-spica cast

or short-arm constructs that leave the:

Thumb interphalangeal joint free.

Current practice often favors:

Short-arm immobilization

for stable fractures.

Surgical Fixation of Nondisplaced Fractures

Percutaneous fixation of selected nondisplaced fractures may permit:

Earlier return to work or sport

and sometimes faster radiographic union.

However, long-term:

Strength

Range of motion

and functional results are often similar to cast treatment.

Routine surgery for every nondisplaced fracture is therefore:

Not required.

Displaced Fractures

Displaced scaphoid fractures generally require:

Reduction and internal fixation

because nonoperative treatment carries a higher risk of:

Nonunion

Malunion

and carpal collapse.

Proximal Pole Fractures

Proximal pole fractures are frequently treated surgically because of their:

Limited blood supply

and increased risk of:

Avascular necrosis

and

Nonunion.

Competitive Athletes

Surgical fixation may be considered in competitive athletes when:

Earlier functional recovery

and return to sport are important, provided the risks and benefits are appropriate.

Activity

Heavy lifting and sports should generally be avoided until:

Fracture union is established

and the wrist is:

Pain free.

Return-to-play decisions may be modified for:

Elite or professional athletes

using sport-specific protection and imaging.

Physical Therapy

During immobilization, therapy should preserve:

Finger motion

Edema control

and general hand function.

After immobilization, rehabilitation helps restore:

Wrist motion

Grip strength

Forearm strength

and function.

Surgery

Screw Fixation

Most displaced fractures are treated with:

Reduction

followed by fixation using a:

Headless compression screw.

Headless Compression Screws

These implants are designed to:

Compress the fracture

while remaining buried within the bone so they do not protrude into the:

Radiocarpal

or

Midcarpal joint.

Cannulated Technique

Cannulated screws can be placed over a:

Guidewire

to improve:

Central positioning

and

Fracture compression.

Percutaneous Fixation

Selected fractures can be fixed:

Percutaneously

to minimize soft-tissue disruption.

Alternative Fixation

When a screw alone cannot provide adequate stability, alternatives may include:

K-wires

or

Scaphoid-specific plates

particularly in complex fractures with:

Bone loss

Comminution

or

Severe deformity.

Chronic Fracture and Nonunion

Scaphoid nonunion generally requires:

Reduction

Internal fixation

and often:

Bone grafting.

Bone Grafting

Bone graft may be:

Nonvascularized

or

Vascularized.

Selection depends on:

Fracture location

Degree of sclerosis

Previous surgery

Bone loss

and presence of:

Proximal pole avascular necrosis.

Vascularized Bone Graft

Vascularized grafts are more commonly considered when there is:

Proximal pole AVN

or a difficult chronic nonunion.

Humpback Deformity

Chronic waist nonunion may result in:

Flexion deformity of the scaphoid

known as a:

Humpback deformity.

This alters carpal mechanics and may contribute to:

DISI deformity

and progressive wrist arthritis.

Scaphoid Nonunion Advanced Collapse

Untreated nonunion can produce a characteristic pattern of progressive arthritis termed:

Scaphoid nonunion advanced collapse

or

SNAC wrist.

Salvage Procedures

When advanced arthritis has developed, reconstructive options may include:

Proximal row carpectomy

or

Partial wrist fusion.

Radial Styloidectomy

Selected early-stage arthritic changes localized near the radial styloid may occasionally be treated with:

Radial styloidectomy.

This is generally part of a broader procedure rather than definitive treatment of an unstable nonunion.

Referral

Orthopaedic or hand-surgery referral is particularly appropriate for:

Displaced fractures

Proximal pole fractures

Associated carpal dislocation

High-energy injuries

Suspected nonunion

Delayed presentation.

Follow-Up

Patients should be followed clinically and radiographically until:

Fracture union

and functional recovery are achieved.

Follow-Up Interval

Acute fractures may be reviewed approximately every:

2–6 weeks

depending on fracture characteristics and treatment.

CT for Union

CT is highly useful for evaluating:

Trabecular bridging across the fracture

and is often considered the most accurate imaging method for determining:

Bony union.

Its disadvantage is:

Radiation exposure.

Duration of Monitoring

Overall treatment and rehabilitation commonly extend over approximately:

12–20 weeks

although proximal fractures and nonunions may require substantially longer.

Prognosis

More than:

90% of nondisplaced fractures

heal with appropriate treatment.

Nondisplaced Fractures

Long-term results are generally:

Excellent

when diagnosis is early and immobilization is appropriate.

Surgical Versus Nonsurgical Treatment

For nondisplaced fractures, surgery may provide:

Earlier union or return to activity

but also introduces risks related to:

Hardware

Infection

Joint penetration

and other operative complications.

Displaced Fractures

Displaced fractures have a higher risk of:

Nonunion

when treated nonoperatively.

Appropriate reduction and fixation generally provide:

Good functional outcomes.

Nonunion Prognosis

Scaphoid nonunion can often be treated successfully with:

Internal fixation

and

Bone grafting

provided advanced arthritis has not already developed.

Complications

Nonunion

Nonunion is one of the most important complications.

Risk is greatest with:

Proximal pole fractures

Displacement

Delayed diagnosis

and inadequate immobilization.

Malunion

Malunion may produce:

Humpback deformity

and abnormal carpal alignment.

Avascular Necrosis

The proximal pole is particularly vulnerable to:

Avascular necrosis

because of its retrograde blood supply.

Post-Traumatic Arthritis

Untreated nonunion or malunion may eventually produce:

Radiocarpal

and

Midcarpal arthritis.

Wrist Instability

Altered scaphoid geometry can lead to:

Carpal instability

and progressive collapse.

Hardware Complications

Surgical fixation may result in:

Prominent hardware

Screw penetration

Loss of fixation

Hardware irritation

or need for:

Revision surgery.

Complex Regional Pain Syndrome

A small number of patients may develop:

Complex regional pain syndrome, historically called reflex sympathetic dystrophy.

Iatrogenic Injury

Operative complications may include injury to:

Sensory nerves

Tendons

or

Articular cartilage.

Patient Monitoring

Follow-up should document:

Pain

Snuffbox tenderness

Wrist range of motion

Grip strength

Radiographic healing

and eventual:

Return to activity.

Key Principle

Scaphoid fracture is the most common carpal fracture and must be suspected after a fall onto an extended wrist, particularly when there is anatomic snuffbox or scaphoid tubercle tenderness.

The diagnosis may be missed on initial radiographs, so persistent clinical suspicion should prompt:

Immobilization and early MRI or CT evaluation.

Nondisplaced fractures usually heal with:

Appropriate immobilization, whereas displaced and proximal pole fractures generally require:

Internal fixation because of their increased risk of nonunion and avascular necrosis.

Failure to achieve union can ultimately lead to:

Humpback deformity, carpal instability, SNAC wrist, and progressive arthritis.