Elbow fracture Dislocations- Case Studies

Courtesy:Saqib Rehman MD

 

Epidemiology

• Account for 11–28% of all elbow injuries

• Posterior dislocation is most common (80–90%)

• Annual incidence: 6–8 per 100,000 population

• Simple dislocations: ligamentous injury only

• Complex dislocations: associated fracture (?50%)

• Highest incidence: 10–20 years, commonly sports-related

• Recurrent elbow dislocation is uncommon

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Anatomy of the Elbow Joint

• A modified hinge joint with high intrinsic stability due to:

  • Joint congruity

  • Balanced muscle forces

  • Strong ligamentous constraints

Articulations

• Ulnotrochlear joint – hinge motion

• Radiocapitellar joint – rotation and valgus stability

• Proximal radioulnar joint – forearm rotation

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Elbow Stability

Anterior–Posterior Stability

• Trochlea–olecranon fossa (extension)

• Coronoid process

• Radiocapitellar articulation

• Muscle forces (biceps, triceps, brachialis)

• Anterior joint capsule contributes to ulnohumeral stability

Valgus Stability

• Medial Collateral Ligament (MCL) complex

  • Anterior band = primary stabilizer

  • Provides:

    • ~30% valgus stability in full extension

    • 50% valgus stability at 90° flexion

  • Resection causes gross instability except in extension

Varus Stability

• Lateral Ulnar Collateral Ligament (LUCL) – static stabilizer

• Anconeus muscle – dynamic stabilizer

Lateral Ligaments

• Prevent posterior subluxation and rotational instability

• Deficiency leads to posterolateral rotatory instability (PLRI)

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Normal and Functional Range of Motion

• Normal ROM

  • Flexion–extension: 0–150°

  • Supination: 85°

  • Pronation: 80°

• Functional ROM

  • Flexion arc: 30–130°

  • Supination: 50°

  • Pronation: 50°

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Mechanism of Injury

• Most commonly due to fall on an outstretched hand (FOOSH)

• Levering force disengages olecranon from trochlea with translation

Types by Mechanism

• Posterior dislocation

  • Hyperextension

  • Valgus stress

  • Arm abduction

  • Forearm supination

• Anterior dislocation

  • Direct blow to posterior forearm

  • Elbow in flexion

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Capsuloligamentous Injury Pattern

• Most elbow dislocations involve injury to all stabilizers

• Exceptions:

  • Transolecranon fracture-dislocations

  • Large coronoid fractures

• Injury progresses lateral ? medial (Horii circle)

• Elbow may dislocate with anterior MCL band intact

• Variable injury to common flexor and extensor origins

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Clinical Evaluation

• Guarded posture with swelling and deformity

• Mandatory neurovascular examination:

  • Before reduction

  • After reduction

  • Serial exams if swelling is severe

Vascular Assessment

• Angiography indicated if perfusion not restored post-reduction

• Radial pulse may persist despite brachial artery injury

• Warm, perfused hand with absent pulse ? likely arterial spasm

Additional Signs

• Medial ecchymosis (MCL disruption) appears 3–5 days post-injury

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Associated Injuries

• Fractures

  • Radial head

  • Coronoid process

  • Capitellum / trochlea (less common)

• Neurovascular

  • Ulnar nerve (most common)

  • Anterior interosseous nerve

  • Brachial artery (especially open injuries)

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Radiographic Evaluation

• Standard AP and lateral elbow radiographs

• Assess:

  • Ulnohumeral congruity

  • Radiocapitellar alignment

• Look for associated fractures

• Valgus stress views (post-reduction) for MCL injury

• CT scan for complex fracture-dislocations

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Classification of Elbow Dislocations

By Complexity

• Simple – ligamentous

• Complex – fracture associated

By Direction of Ulna Displacement

• Posterior

• Posterolateral

• Posteromedial

• Lateral

• Medial

• Anterior

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Fracture-Dislocations of the Elbow

Radial Head Fractures

• Occur in 5–11%

Epicondylar Fractures

• Occur in 12–34%

• Can block reduction due to fragment entrapment

Coronoid Process Fractures (5–10%)

• Usually avulsion by brachialis

Regan–Morrey Classification

• Type I – Tip avulsion

• Type II – ?50% of coronoid

• Type III – >50% of coronoid

?? Fracture-dislocations have higher risk of chronic instability

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Common Injury Patterns

• Posterior dislocation + radial head fracture

• Terrible triad:

  • Elbow dislocation

  • Radial head fracture

  • Coronoid fracture (usually Type I or II)

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Types of Elbow Instability

• Posterolateral rotatory instability (PLRI)

• Varus posteromedial rotational instability

• Olecranon fracture-dislocations

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Instability Scale (Morrey)

• Type I – LUCL injury; positive pivot shift

• Type II – Perched dislocation; capsule + LUCL disrupted

• Type IIIa – Posterior dislocation; posterior MCL disrupted

• Type IIIb – Gross instability; complete MCL disruption

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General Treatment Principles

• Restore elbow stability

• Restore trochlear notch (coronoid + olecranon)

• Maintain radiocapitellar contact

• LCL is more critical than MCL in most cases

• MCL usually heals with early motion and rarely needs repair

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Simple Elbow Dislocation

Non-Operative Management

• Closed reduction under sedation/anesthesia

• Posterior dislocations reduced in flexion with traction

• Post-reduction:

  • Neurovascular reassessment

  • Stability assessment through ROM

• Stable elbows:

  • Splint at 90°

  • Hinged brace after 3–5 days

• Hinged brace for 6 weeks

• Physical therapy after 6 weeks

• Full recovery: 3–6 months

Closed Reduction Techniques

• Parvin method – Prone traction, no assistant

• Meyn & Quigley method – Forearm hanging off stretcher

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Operative Indications (Simple Dislocation)

• Instability beyond 30° flexion

• Recurrent subluxation/dislocation

• Associated unstable fractures

Surgical Steps

• LCL repair first

• MCL repair only if instability persists

• Hinged external fixator if required

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Elbow Fracture-Dislocations

Non-Operative

• Rarely appropriate

• High risk of stiffness and instability

Operative Management

• Radial head fixation or replacement

• Coronoid fixation

• LCL repair

• Acute MCL repair usually not required

• Early motion encouraged once stability restored

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Terrible Triad Injuries

• Highly unstable injury pattern

• Requires:

  • Coronoid fixation or capsular repair

  • Radial head fixation/replacement

  • LCL repair

• Radial head excision alone is contraindicated

• External fixation or MCL repair if instability persists

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Complications

• Elbow stiffness (most common)

• Neurologic injury

  • Ulnar nerve most frequent

• Vascular injury

  • Brachial artery

• Compartment syndrome

• Persistent instability

• Post-traumatic arthrosis

• Heterotopic ossification

  • Increased risk with repeated manipulation

  • Avoid forceful stretching

  • Indomethacin and radiation prophylaxis are controversial

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Key Take-Home Messages

• Posterior elbow dislocation is most common

• LCL is the key stabilizer in traumatic instability

• Early, stable motion prevents stiffness

• Fracture-dislocations require surgical management

• Terrible triad injuries demand systematic reconstruction