PIP Joint Fracture-Dislocations

Definition

• Injury involving dislocation of the proximal interphalangeal (PIP) joint with an associated fracture
• Most commonly involves the base of the middle phalanx articular surface

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Importance

• Commonly missed injury
• Delayed or inadequate treatment can lead to:
  • Stiffness
  • Instability
  • Post-traumatic arthritis
  • Loss of function

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Anatomy

The PIP joint is a hinge joint.

Stability Provided By

• Bony congruity
• Volar plate
• Collateral ligaments
• Central slip and extensor mechanism

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Mechanism of Injury

Usually caused by:

• Axial loading
• Hyperextension
• Rotational force

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Types of PIP Fracture-Dislocations

1. Dorsal Fracture-Dislocation

Most common type

Mechanism:

• Hyperextension injury

Pathology:

• Volar lip fracture of middle phalanx
• Middle phalanx displaces dorsally

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2. Volar Fracture-Dislocation

Less common

Associated injury:

• Central slip injury

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3. Lateral Dislocation

Mechanism:

• Collateral ligament injury

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Classification by Articular Involvement

<30% Articular Surface

• Usually stable

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30–50% Articular Surface

• Tenuous stability

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>50% Articular Surface

• Usually unstable

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Clinical Features

• Pain
• Swelling
• Deformity
• Restricted movement
• Tenderness around PIP joint

Chronic cases may present with:

• Stiffness
• Functional limitation

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Imaging

Required Views

• AP view
• Lateral view
• Oblique view

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Assess On Imaging

• Direction of dislocation
• Fragment size
• Percentage of articular involvement
• Joint congruity
• Persistent subluxation

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Important Radiological Concept

Joint Congruity is Critical

Look for:

• Smooth gliding articulation
• Absence of hinging
• No persistent subluxation

Persistent hinging or subluxation indicates instability.

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Treatment Goals

• Restore congruent reduction
• Maintain stability
• Allow early mobilization
• Prevent stiffness and arthritis

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Treatment

Stable Injuries

Non-operative Management

• Extension block splinting
• Buddy taping in selected simple injuries
• Early supervised range of motion exercises

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Dorsal Fracture-Dislocation

Common Treatment Options

1. Extension Block Splinting

• Prevents hyperextension
• Maintains stable reduction

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2. Extension Block Pinning

• Used for unstable injuries

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3. Open Reduction and Internal Fixation (ORIF)

Indication:

• Large fracture fragments

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4. Dynamic External Fixation

Indications:

• Comminuted fractures
• Unstable injuries

Advantages:

• Uses ligamentotaxis
• Allows early motion

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5. Volar Plate Arthroplasty

Used in:

• Selected chronic injuries

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6. Hemi-Hamate Arthroplasty

Used for:

• Severe chronic injuries
• Salvage situations
• Extensive volar lip loss

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Volar Fracture-Dislocation

Treatment Principles

• Usually immobilized in extension
• Large fragments may require fixation
• Always assess for central slip injury

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Dynamic External Fixation

Advantages

• Maintains reduction through ligamentotaxis
• Allows early controlled motion
• Useful for unstable and comminuted fractures

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Complications

• Joint stiffness
• Residual instability
• Recurrent subluxation
• Post-traumatic arthritis
• Flexion deformity
• Extension lag
• Reduced grip strength

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Key Clinical Pearls

• Dorsal fracture-dislocation is more common than volar fracture-dislocation
• <30% articular involvement is usually stable

• 50% articular involvement is usually unstable

• Early mobilization after stable reduction is essential
• Smooth gliding congruent reduction is more important than perfect radiographic appearance
• Missed injuries lead to poor long-term functional outcome