Chauffeur's Fractures

Hand-crank starters on early automobiles would backfire, causing the crank to spin rapidly backwards. This delivered a direct blow to the radial aspect of the wrist, specifically impacting the radial styloid. This mechanism is now historical but gives the fracture its name.

The understanding of this mechanism highlights the injury pattern well.

Forced ulnar deviation: The scaphoid is driven against the radial styloid, causing an avulsion or shear fracture. Common in falls, sports injuries, and motor vehicle accidents.

Direct trauma: Impact to the radial wrist can fracture the styloid directly.

Greater arc injury: The radial styloid fracture may occur as part of a perilunate injury pattern, where the injury propagates through bone rather than through the scapholunate ligament.

These mechanisms account for most modern presentations of this injury.

The radial styloid acts as a buttress against the scaphoid during ulnar deviation. When excessive force is applied, either the styloid fractures (greater arc) or the scapholunate ligament ruptures (lesser arc).

The scaphoid impacts the radial styloid during forced ulnar deviation, creating either a shear fracture (larger fragment) or avulsion fracture (smaller fragment from ligament tension).

Understanding these biomechanics explains the high rate of associated ligament injuries.

The most clinically useful classification is based on fragment size, which directly guides treatment decisions.

Small Fragment (Under 5mm): Cortical avulsion with minimal articular involvement. May be managed non-operatively or with excision if symptomatic and SL ligament intact.

Medium Fragment (5-15mm): Articular involvement with variable stability. Requires ORIF with headless compression screws for anatomic reduction.

Large Fragment (Over 15mm): Significant articular surface, may be comminuted. Requires plate fixation or multiple screws for stable fixation.

Fragment size is the primary determinant of treatment strategy.

The perilunate injury spectrum describes how energy dissipates through the carpus during hyperextension injuries.

Greater Arc Injury: Energy propagates through bone (fractures) rather than ligaments. Includes radial styloid fracture (Chauffeur's), scaphoid fracture, capitate fracture, triquetral fracture, and ulnar styloid fracture. The fracture pattern follows the arc around the lunate through bone.

Lesser Arc Injury: Energy propagates through ligaments with perilunate dislocation. Includes scapholunate ligament rupture, lunotriquetral ligament rupture, and dorsal radiocarpal ligament rupture. No fractures occur - this is a pure ligamentous injury.

In a Chauffeur's fracture, the radial styloid breaks INSTEAD of the scapholunate ligament rupturing, making it a greater arc injury component.

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Undisplaced, Small Fragment, SL Intact: Non-operative with cast immobilization 4-6 weeks.

Displaced Small Fragment, SL Intact: Consider fragment excision if symptomatic after trial of conservative management.

Medium Fragment (5-15mm): ORIF with headless compression screws via volar or dorsal approach.

Large Fragment (Over 15mm): ORIF with mini-fragment plate or multiple screws.

Any Fragment with SL Injury: ORIF of styloid plus SL ligament repair or reconstruction at the same surgery.

This algorithm guides clinical decision-making for optimal outcomes.

Swelling: Localized swelling over radial styloid is characteristic. More diffuse swelling suggests associated injuries.

Deformity: Obvious deformity may indicate significant displacement or associated perilunate injury.

Ecchymosis: Bruising over radial wrist develops within 24-48 hours.

Skin integrity: Assess for open injury, especially with high-energy mechanisms.

These inspection findings guide further examination.

Anatomical snuffbox: Tenderness here may indicate scaphoid injury - commonly associated.

Radial styloid: Direct tenderness over the styloid tip is the hallmark finding.

Scapholunate interval: Tenderness dorsally between scaphoid and lunate suggests SL injury.

DRUJ: Palpate for tenderness and stability of the distal radioulnar joint.

A systematic palpation approach ensures no injuries are missed.

Watson's test: Scaphoid shift test for scapholunate instability. Pressure on scaphoid tubercle while moving from ulnar to radial deviation.

Ballottement test: Assess DRUJ stability with forearm in neutral rotation.

Grip strength: Compare to contralateral side - weakness common with wrist injuries.

Range of motion: Document flexion, extension, radial/ulnar deviation, supination/pronation.

These special tests help identify associated ligamentous injuries.

Indications for Conservative Treatment:

• Undisplaced fracture with under 2mm displacement
• Small fragment under 5mm without significant articular involvement
• Minimal articular step-off under 2mm
• Intact scapholunate ligament confirmed on imaging or examination
• Low-demand patient with minimal symptoms

Protocol:

• Short arm cast or splint for 4-6 weeks
• Wrist position in neutral or slight radial deviation
• Serial radiographs at 1, 2, and 4 weeks to monitor for displacement
• Transition to removable splint then hand therapy at 4-6 weeks

Non-operative management is only appropriate when SL ligament integrity is confirmed.

Absolute Surgical Indications:

• Fragment displacement over 2mm
• Articular step-off over 2mm
• Fragment size over 5mm with any displacement
• Associated scapholunate ligament injury (30-50% of cases)
• Greater arc injury or perilunate spectrum
• Open fracture

Fixation Selection by Fragment Size:

• Small fragments with SL injury: Fix SL, consider excision of fragment if truly small
• Medium fragments 5-15mm: Headless compression screws preferred
• Large fragments over 15mm or comminuted: Mini-fragment plate fixation

The key principle is achieving anatomic reduction of the articular surface.

Partial SL Tear: Assess with MRI or arthroscopy. Treat with pinning and repair at same surgery.

Complete SL Tear: Confirm with arthroscopy. Requires open repair or reconstruction at index surgery.

Perilunate Dislocation: Clinical and radiographic diagnosis. Urgent reduction plus K-wire fixation at same surgery.

Scaphoid Fracture: CT or MRI assessment. ORIF of both scaphoid and styloid at same surgery.

TFCC Injury: Assess with MRI or arthroscopy. Repair if causing DRUJ instability, same surgery or staged.

All associated pathology should ideally be addressed at the index surgery for optimal outcomes.

Positioning: Supine with arm on hand table, tourniquet to upper arm.

Incision: Longitudinal incision over FCR tendon, curving radially at wrist crease.

Dissection: Incise FCR sheath, retract tendon ulnarly. Incise floor of sheath to expose pronator quadratus.

Exposure: Elevate pronator quadratus radially to expose fracture. Extend incision distally as needed for radial styloid visualization.

Advantages: Protects superficial radial nerve, excellent visualization, familiar approach.

This approach is preferred for most cases.

Positioning: Same as volar approach.

Incision: Longitudinal incision over dorsal radius, between 1st and 2nd extensor compartments.

Dissection: Develop interval between EPL (3rd compartment) and ECRL/ECRB (2nd compartment).

Exposure: Incise capsule to expose radiocarpal joint and radial styloid.

Advantages: Direct access for dorsal comminution, allows SL ligament inspection.

Disadvantages: Risk to superficial radial nerve, extensor tendon irritation from hardware.

The dorsal approach is useful when combined with ligament assessment.

For complex injuries with both volar styloid component and dorsal ligament pathology, a combined approach may be necessary.

Begin with volar approach for fracture fixation, then add limited dorsal incision for SL ligament assessment and repair.

This maximizes visualization while minimizing soft tissue stripping.

The combined approach is reserved for complex greater arc injuries.

Indications: Medium fragments (5-15mm), non-comminuted fractures.

Technique:

• Reduce fragment anatomically under direct vision
• Hold reduction with K-wire
• Insert guidewire perpendicular to fracture line
• Measure screw length (typically 18-24mm)
• Countersink screw head below articular cartilage
• Remove K-wire after final tightening

Tips: Use cannulated system, bury head completely to avoid chondral damage.

Headless screws provide excellent compression with minimal hardware prominence.

Indications: Large fragments (over 15mm), comminuted fractures, poor bone quality.

Technique:

• Reduce and provisionally fix with K-wires
• Apply mini-fragment plate (2.0-2.4mm)
• Place plate on volar or dorsal surface as appropriate
• Use locking screws in osteoporotic bone
• Ensure plate does not impinge on radiocarpal joint

Tips: Contour plate to match anatomy, avoid excessive soft tissue stripping.

Plate fixation provides stable fixation for complex fracture patterns.

Indications: Small fragments (under 5mm), intact SL ligament confirmed, symptomatic after non-operative trial.

Technique:

• Expose fragment through appropriate approach
• Confirm SL ligament integrity
• Excise fragment sharply
• Smooth remaining styloid edge
• Repair capsule and ligament attachments

Contraindications: SL ligament injury, large fragment, young high-demand patient.

Fragment excision is reserved for specific indications with confirmed ligament integrity.