Pulled Elbow (Nursemaid's Elbow)

1. Clinical Overview

Summary

A Pulled Elbow (Radial Head Subluxation) is the most common upper limb injury in toddlers (1-4 years). It involves the Annular Ligament slipping proximally over the radial head and becoming entrapped in the radiocapitellar joint. The classic mechanism is axial traction on an extended, pronated forearm ("swinging the child"). The child presents with Pseudoparalysis: arm held by the side, pronated, refusing to use it, but not distressed unless moved. Reduction is famously satisfying (immediate fix). [1,2,3]

Key Facts

• The "Popcorn Test": After reduction, the child usually cries briefly, then settles. To confirm success, offer them a treat/toy (Popcorn/Smarties) that requires them to reach out and supinate. If they use the arm spontaneously within 10-15 minutes, it is fixed.
• Mechanism: Traction on a straight arm. (Lifting child by wrists, swinging, pulling child away from danger).
• Age Limit: Rare after age 5. (The radial head grows wider than the neck, preventing the ligament slipping off).

Clinical Pearls

"Hyper-pronation Beats Supination": The traditional teaching is Supination + Flexion. However, RCTs show that Hyper-pronation has a higher first-attempt success rate and is less painful. [4,5]

"No X-rays Needed": If the history is classic (pull) and exam is classic (no swelling), do NOT X-ray. It's purely clinical. X-ray only if reduction fails or mechanism involves a fall. [6]

"The Click": A palpable (sometimes audible) click during the reduction maneuver is the feeling of the ligament snapping back into place. It usually signifies success.

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2. Epidemiology

Demographics

Radial head subluxation is an extremely common paediatric injury, accounting for approximately 20-27% of all upper extremity injuries in children presenting to emergency departments. [7,8]

Age Distribution

• Peak Incidence: 1-4 years of age, with the highest occurrence between 2-3 years. [7,9]
• Under 6 months: Extremely rare (insufficient strength to sublux the ligament).
• After 5 years: Uncommon. By age 5-6, the radial head develops a more bulbous morphology that mechanically prevents annular ligament displacement. [10]
• Adolescents/Adults: Can occur rarely, usually in the context of trauma or hypermobility syndromes.

Sex Distribution

• Female predominance: Slight female preponderance reported in most series (Female:Male ratio approximately 1.2-1.5:1). [7,11]

Laterality

• Left > Right: Left arm is affected in approximately 60-65% of cases. [12,13]
• Rationale: Most parents/caregivers are right-handed and tend to hold the child's left hand when walking, pulling, or swinging, creating the classic traction mechanism.
• Bilateral: Extremely rare (less than 1%), should raise suspicion for alternative diagnosis or non-accidental injury.

Recurrence

• Recurrence Rate: 20-40% of children experience at least one recurrence. [14,15]
• Multiple Recurrences: Some children experience frequent recurrences (> 3 episodes), often until developmental maturation of the radial head around age 5.
• Risk Factors for Recurrence: Younger age at first episode (less than 2 years), hypermobility, parental lack of awareness about prevention.

Socioeconomic Factors

• Healthcare Utilization: One of the most common reasons for paediatric emergency department visits for musculoskeletal complaints.
• Parental Anxiety: Often high due to child's refusal to move arm, despite the benign nature and straightforward treatment.
• Educational Opportunity: Excellent opportunity for parental education on safe handling and injury prevention.

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3. Pathophysiology

Anatomical Basis

The Annular Ligament

• Structure: The annular ligament is a strong fibro-osseous ring that encircles the radial head and neck, inserting on the anterior and posterior margins of the radial notch of the ulna.
• Function: Maintains the radial head in articulation with the proximal radioulnar joint while permitting rotation during pronation/supination.
• Paediatric Characteristics: In young children, the ligament is relatively lax and the attachment is less robust compared to adults.

Developmental Anatomy of the Radial Head

• Birth to Age 3: The radial head is not fully ossified and has a similar diameter to the radial neck (cylindrical shape).
• Age 3-5: Progressive ossification creates a more bulbous, mushroom-shaped radial head.
• After Age 5: The radial head diameter exceeds the neck diameter, creating a mechanical block that prevents proximal migration of the annular ligament. [16]

Mechanism of Subluxation (Step-by-Step)

1. Initiating Event: Sudden longitudinal traction applied to the extended and pronated forearm.

   • Common scenarios: Lifting child by wrists, swinging in circles, pulling child up from ground, yanking child away from danger.

2. Radial Head Displacement: The axial force causes the radial head to move distally relative to the capitellum.

3. Ligament Slippage: As the radius is pulled distally, the relatively lax annular ligament slips proximally over the convex dome of the radial head.

4. Entrapment: When traction is released, the radius recoils proximally, but the annular ligament fails to reduce. Instead, a portion of the ligament becomes trapped (interposed) between the radial head and the capitellum in the radiocapitellar joint.

5. Locked Position: The interposed ligament prevents full pronation/supination and creates pain with attempted movement, particularly supination.

Why It Occurs in Toddlers

Anatomical Vulnerabilities:

• Underdeveloped Radial Head: Lacks the bulbous shape that provides mechanical resistance in older children and adults. [16]
• Ligament Laxity: The annular ligament in toddlers is relatively loose and elastic, with less robust bony attachments.
• Thin Ligament: The annular ligament is thinner in young children (approximately 1-2mm) compared to adults.
• Incomplete Ossification: The radial head ossification center appears around age 3-5, so younger children have a largely cartilaginous radial head.

Biomechanical Factors:

• Arm Length Leverage: The extended arm position maximizes the longitudinal force transmitted to the proximal radius.
• Pronated Position: Pronation tightens the radiocapitellar joint and positions the ligament for easier displacement.
• Sudden Force: Rapid, unexpected traction doesn't allow protective muscle contraction.

Why It Stops After Age 5

By approximately age 5-6 years, several protective changes occur:

• Radial Head Morphology: The radial head becomes significantly wider than the neck, creating a mechanical "stop" that prevents the annular ligament from slipping over it. [10,16]
• Ligament Strengthening: The annular ligament becomes thicker and has stronger bony attachments.
• Increased Awareness: Older children are better able to communicate discomfort and resist being pulled inappropriately.

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4. Clinical Presentation

History

Classic Mechanism (85-90% of cases)

• Sudden Traction Event: Parent reports pulling, lifting, or swinging the child by the hand or wrist. [17]
• Common Scenarios:
  • "I was swinging him between me and my partner"
  • "I pulled her up from the floor by her hands"
  • "I grabbed his wrist to stop him running into traffic"
  • "She was hanging from my arm/hand"
• Immediate Response: Child cries briefly at the moment of traction, then stops crying but refuses to use the arm.

Atypical Mechanisms (10-15% of cases)

• Rolling Over in Bed: Child may roll onto arm during sleep; parent finds arm "not working" in morning.
• Pushing Through Cot Bars: Arm gets caught and twisted.
• Uncertain History: Parents may not witness or recall a specific event, particularly in childcare settings.
• Non-Accidental Injury (NAI): Consider if history is inconsistent, unexplained, or there are multiple injuries or concerning features.

Timing

• Immediate Onset: Symptoms begin within seconds of the traction event.
• Delayed Presentation: Some parents wait hours to days if the child seems relatively comfortable, particularly if reduced parental concern or limited healthcare access.

Symptoms

• Refusal to Use Arm: The cardinal symptom. Child will not reach for objects, wave, or use the affected limb.
• Pain: Typically mild to moderate. Child is not in severe distress but becomes upset if someone attempts to move the arm, particularly into supination.
• No Swelling: Parents should report no visible swelling, deformity, or bruising.
• Non-localization: Young children often cannot localize pain; parents may think the shoulder or wrist is injured rather than the elbow.

Signs

General Inspection

• Pseudoparalysis: Arm hangs limply by the side, appearing "paralyzed" or "dead."
• Protective Posture: Arm held in a characteristic position:
  • Elbow: Slight flexion (15-30 degrees)
  • Forearm: Pronated (palm facing backward or against body)
  • Shoulder: May be slightly internally rotated
• No Distress at Rest: Child is comfortable and playing normally with the other hand, not crying unless the affected arm is touched.

Palpation

• No Swelling: Crucial negative finding. Any swelling suggests alternative diagnosis (fracture, infection).
• No Deformity: The elbow contour is normal; no visible or palpable bony abnormality.
• Mild Tenderness: May be slight tenderness over the radial head (anterolateral elbow), but not marked.
• No Crepitus: No grinding sensation on palpation.
• No Warmth/Erythema: Rules out infectious/inflammatory process.

Movement

• Active Movement: Child refuses to move arm voluntarily.
• Passive Movement:
  • Flexion/Extension: Usually tolerated with minimal discomfort.
  • Supination: Markedly limited and painful (most sensitive finding).
  • Pronation: Usually less painful, may be partially maintained.
• Shoulder/Wrist: Full, pain-free range of motion (helps localize pathology to elbow).

Neurovascular Examination

• Radial Pulse: Normal, equal to contralateral side.
• Capillary Refill: less than 2 seconds.
• Sensation: Intact (though difficult to assess formally in distressed toddler).
• Motor: Cannot formally assess due to pain, but no signs of nerve injury (e.g., wrist drop).

Diagnostic Triad

The diagnosis of pulled elbow is primarily clinical, based on three key features:

1. Appropriate Age: 1-4 years (peak 2-3 years)
2. Classic Mechanism: Sudden axial traction on extended, pronated arm
3. Characteristic Examination:
   • Arm held pronated and slightly flexed
   • Refuses to use arm (pseudoparalysis)
   • No swelling, deformity, or significant tenderness
   • Pain with attempted supination

If all three are present, the positive predictive value for radial head subluxation is > 95%. [6,17]

Red Flags Requiring Further Investigation

• Visible Swelling or Deformity: Suggests fracture, not subluxation.
• Fall or Direct Trauma: Mechanism inconsistent with pulled elbow; consider fracture.
• Point Tenderness Over Bone: Suggests fracture.
• Age less than 6 months or > 6 years: Unusual age; consider alternative diagnosis.
• Bilateral Presentation: Extremely rare; consider systemic process or NAI.
• Fever or Systemic Symptoms: Consider septic arthritis or osteomyelitis.
• Failure to Reduce After 2-3 Attempts: May indicate incorrect diagnosis.
• Non-weight Bearing (if lower limb equivalent): Completely different presentation.

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5. Differential Diagnosis

Must Not Miss

1. Supracondylar Fracture

   • Key Differences: History of fall onto outstretched hand (FOOSH), visible swelling/deformity, severe pain, may have neurovascular compromise (especially anterior interosseous nerve).
   • Why Dangerous: Risk of compartment syndrome, neurovascular injury, Volkmann's ischemic contracture.
   • Management: Urgent orthopaedic referral, immediate immobilization.

2. Septic Arthritis of Elbow

   • Key Differences: Fever, severe pain, elbow held in 70° flexion (position of maximal capsular distension), effusion, systemic unwellness, inflammatory markers elevated.
   • Why Dangerous: Rapid cartilage destruction, permanent joint damage, sepsis.
   • Management: Emergency orthopaedic washout, IV antibiotics.

3. Non-Accidental Injury (NAI)

   • Key Differences: Inconsistent history, multiple injuries at different stages, delay in presentation, spiral fractures (humeral or forearm), suspicious bruising patterns.
   • Why Dangerous: Safeguarding issue, risk of further harm.
   • Management: Safeguarding referral, skeletal survey if indicated.

Other Fractures to Consider

4. Radial Neck Fracture

   • Differences: Usually follows fall, swelling over proximal radius, crepitus may be palpable, X-ray diagnostic.
   • Examination: Tenderness directly over radial neck, pain with forearm rotation.

5. Lateral Condyle Fracture

   • Differences: Localized swelling over lateral epicondyle, may have crepitus, X-ray shows fracture (can be subtle).
   • Management: Often requires surgical fixation if displaced.

6. Clavicle Fracture

   • Differences: Toddlers may present with pseudoparalysis of whole arm; swelling/deformity over clavicle, pain with shoulder movement.
   • Clue: Parents may report "won't move arm" but pathology is at shoulder girdle, not elbow.

Less Common Differentials

7. Elbow Dislocation

   • Differences: Rare in toddlers, requires significant force, gross deformity, complete loss of elbow anatomy.

8. Radial Head Dislocation (Congenital or Traumatic)

   • Differences: Radial head palpable out of position (posterolateral), often congenital in this age group.

9. Brachial Plexus Injury (Erb's Palsy - Acute Traction)

   • Differences: Whole arm affected, not just elbow; may have wrist drop or claw hand; neurological deficit.

10. Osteomyelitis

    • Differences: Fever, severe pain, unwillingness to move limb, elevated inflammatory markers, focal bony tenderness.

Distinguishing Features Table

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6. Investigations

General Principle: Clinical Diagnosis

Radial head subluxation is a clinical diagnosis. Investigations are typically not required if the presentation is classic. [6,18]

Indications for X-ray:

• Uncertain mechanism (no clear traction history)
• History of fall or direct trauma
• Any visible swelling, deformity, or bruising
• Significant localized tenderness over bone
• Age outside typical range (less than 1 year or > 5 years)
• Failed reduction after 2-3 attempts
• Concern for non-accidental injury

X-Ray Findings

Normal Pulled Elbow

• Bony Structures: Entirely normal. No fracture, dislocation, or bony abnormality.
• Soft Tissues: May be normal or show minimal soft tissue prominence (absent fat pad sign is reassuring).
• Radiocapitellar Line: Maintained (line drawn through radial shaft should bisect capitellum on all views).
• Limitation: The annular ligament is not visible on X-ray (soft tissue structure), so subluxation cannot be directly visualized.

Paediatric Elbow X-Ray Interpretation Pearls

• Standard Views: AP and lateral views of elbow.
• Ossification Centers: Remember CRITOE mnemonic (Capitellum 1yr, Radial head 3yr, Internal/medial epicondyle 5yr, Trochlea 7yr, Olecranon 9yr, External/lateral epicondyle 11yr).
• Young Children: Radial head may not be ossified, so radiocapitellar relationship assessed using radial shaft line.
• Fat Pad Sign:
  • Anterior Fat Pad: Small anterior sail sign can be normal.
  • Posterior Fat Pad: Never normal; suggests effusion/fracture.

Why Not Routine X-Rays?

1. Unnecessary Radiation: Young children are particularly vulnerable to radiation; ALARA principle (As Low As Reasonably Achievable). [6]
2. No Diagnostic Value: X-ray does not show soft tissue subluxation; cannot confirm or exclude diagnosis.
3. Delayed Treatment: Waiting for X-ray delays a simple, safe reduction that could provide immediate relief.
4. Cost-Ineffective: Adds cost without clinical benefit in straightforward cases.
5. Spontaneous Reduction: Some cases reduce spontaneously during X-ray positioning (arm extended and supinated for AP view), leading to false reassurance.

When X-Ray is Valuable

• Failed Reduction: If reduction attempts fail, X-ray helps identify occult fracture (e.g., undisplaced radial neck fracture, subtle lateral condyle fracture).
• Uncertain Diagnosis: Atypical history or examination findings warrant imaging to rule out fracture.
• Medicolegal Documentation: In cases of suspected NAI, skeletal survey is performed.

Other Investigations

Generally not required:

• Ultrasound: Can show annular ligament displacement and radiocapitellar effusion, but not routinely used (time-consuming, operator-dependent, not necessary for diagnosis). [19]
• Blood Tests: Not indicated unless suspecting infection (septic arthritis) or systemic illness.
• MRI/CT: No role in acute diagnosis.

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7. Management

Initial Assessment (ABC Approach Not Typically Required)

Pulled elbow is not a life-threatening injury. Initial assessment focuses on:

1. Confirming Diagnosis: History + Examination triad (age, mechanism, examination).
2. Excluding Red Flags: No swelling, no trauma, appropriate age.
3. Explaining to Parents: What has happened and what will be done.

Reduction Techniques

Two primary methods exist, both performed without anesthesia or sedation:

1. Hyperpronation Method (FIRST-LINE) [4,5]

Evidence: Multiple RCTs and meta-analyses show hyperpronation has a higher first-attempt success rate (89-95%) compared to supination-flexion (77-85%), and is less painful. [4,5]

Technique (Step-by-Step):

1. Positioning:

   • Clinician sits or stands facing the child.
   • Child can be on parent's lap (provides comfort and restraint).
   • Affected arm is positioned in front of child.

2. Grip:

   • One hand (usually clinician's non-dominant hand) stabilizes the elbow:
     • Thumb placed over the radial head (anterolateral aspect of elbow).
     • Fingers wrap around the posterior elbow and distal humerus.
   • Other hand (dominant hand) grasps the child's hand as if shaking hands:
     • Clinician's palm against child's palm, thumb around dorsum of hand.

3. Maneuver:

   • With firm, steady pressure, rapidly and fully pronate the child's forearm (turn palm face down).
   • Some clinicians combine pronation with gentle extension of the elbow (straightening).
   • Apply firm pressure—tentative movements are less likely to succeed.

4. Click:

   • A palpable (and sometimes audible) click is felt under the thumb over the radial head.
   • This represents the annular ligament reducing back to its normal position.
   • Absence of click: Doesn't always mean failure; some successful reductions occur without palpable click.

5. Immediate Response:

   • Child typically cries briefly (a few seconds) from the movement.
   • Crying then stops, and child becomes more comfortable.

Technical Points for Hyperpronation:

• Speed and Confidence: The maneuver must be performed briskly and confidently. Slow, tentative pronation is painful and less likely to succeed.
• Force Required: Significant force is needed. Clinicians inexperienced with the technique may under-pronate.
• Radial Head Palpation: Keeping thumb on radial head allows clinician to feel the reduction click and confirm position.
• Parental Warning: Warn parents that the child will cry briefly, but this is normal and doesn't mean harm is being done.
• Elbow Position: Some advocate starting with elbow in slight flexion; others prefer extension. Both work; key is forceful pronation.

2. Supination-Flexion Method (ALTERNATIVE/SECOND-LINE) [1,2]

Evidence: Traditional method taught for decades, effective but slightly lower success rate than hyperpronation.

Technique (Step-by-Step):

1. Positioning:

   • Similar setup: child on parent's lap, clinician facing child.

2. Grip:

   • One hand stabilizes elbow with thumb on radial head.
   • Other hand grasps child's wrist or hand.

3. Maneuver:

   • First: Fully supinate the forearm (turn palm to face ceiling).
   • Then: While maintaining supination, flex the elbow rapidly to bring hand toward shoulder (as if child is touching shoulder with hand).

4. Click:

   • Click felt during the flexion component, as the radial head rotates and the ligament reduces.

5. Immediate Response:

   • Similar to hyperpronation: brief cry, then settling.

Why Hyperpronation is Preferred:

• Higher success rate on first attempt. [4,5]
• Perceived as less painful by parents and some clinicians.
• Single-plane motion (pronation) vs. two-step motion (supination then flexion).

Post-Reduction Assessment

Immediate (0-5 minutes)

• Crying Subsides: Child should stop crying within 1-2 minutes.
• Increased Comfort: Child becomes noticeably more comfortable and less protective of arm.

Functional Recovery (10-15 minutes)

• Spontaneous Use: Within 10-15 minutes, most children will begin using the arm spontaneously.
• "Popcorn Test" or Toy Test:
  • Offer the child a desirable object (toy, snack, phone) that requires use of both hands or reaching.
  • If child reaches out, grasps object, and supinates to bring it to mouth or play, reduction is confirmed.
• Full Range of Motion: By 15 minutes, most children have full active range of motion.

Success Criteria

• Clinical Success: Child using arm normally within 15 minutes.
• Click Felt: Palpable click during maneuver (though not always present even in successful reduction).
• No Further Pain: Child comfortable with full movement.

Failed Reduction

Definition: No palpable click AND child still refusing to use arm after 15-20 minutes.

Approach:

1. Second Attempt: Try alternative method (if hyperpronation failed, try supination-flexion, or vice versa).
2. Wait and Reassess: Sometimes there is a "pain memory" period; child may take up to 30 minutes to regain confidence in using the arm even after successful reduction.
3. Third Attempt: Consider third attempt with different clinician or after further waiting.

After Multiple Failed Attempts (typically after 2-3 attempts):

• X-Ray: Obtain AP and lateral elbow X-rays to exclude fracture (particularly undisplaced radial neck fracture or occult lateral condyle fracture).
• If X-Ray Normal:
  • Collar and Cuff Sling: Provide comfort sling for 24-48 hours.
  • Spontaneous Reduction: Many cases reduce spontaneously with normal movement within 24 hours.
  • Safety-Net Advice: Parents advised to return if no improvement in 24-48 hours.
• If X-Ray Shows Fracture: Manage fracture appropriately (orthopaedic referral if displaced).

Analgesia

• Generally Not Required: Most children do not need analgesia after successful reduction.
• Pre-Reduction: Analgesia prior to reduction is not necessary and may delay treatment.
• Post-Reduction: If child remains uncomfortable after reduction:
  • Paracetamol: Standard dose (15mg/kg every 4-6 hours, max 4 doses/24h).
  • Ibuprofen: 10mg/kg every 6-8 hours (if no contraindications).
• Avoid Opioids: Not indicated for this injury.

Immobilization

• Not Required: No sling, splint, or immobilization needed after successful reduction.
• Exception: If failed reduction and plan for spontaneous reduction, a broad arm sling (collar and cuff) provides comfort.

Follow-Up

• No Routine Follow-Up: Children who achieve full recovery after reduction do not require routine follow-up.
• Safety-Net Advice: Parents advised to return if:
  • Arm not being used normally by next day.
  • Swelling develops.
  • Child becomes increasingly distressed.

Evidence for Reduction Techniques

Landmark Studies:

1. Macias et al. (1998): First RCT comparing supination-flexion vs. hyperpronation. Found hyperpronation had 92% success vs. 80% for supination-flexion. [4]

2. Krul et al. (2017) - Cochrane Review: Systematic review of 9 RCTs (n=906 children). Concluded:

   • Hyperpronation: 89% first-attempt success
   • Supination-flexion: 77% first-attempt success
   • Lower pain scores with hyperpronation
   • Recommendation: Hyperpronation should be first-line technique. [5]

3. Bek et al. (2009): RCT showing hyperpronation had 95% success vs. 78% for supination-flexion, with significantly less pain. [20]

Clinical Bottom Line: Current evidence strongly supports hyperpronation as first-line reduction technique for pulled elbow.

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8. Recurrence and Prevention

Recurrence Rates

• Overall Recurrence: 20-40% of children experience at least one recurrence. [14,15]
• Multiple Recurrences: Approximately 5-10% have recurrent episodes (≥3 times).
• Age Effect: Recurrence more common if first episode occurs before age 2 years.
• Natural Resolution: Virtually all children "grow out of it" by age 5-6 years due to radial head development.

Risk Factors for Recurrence

1. Young Age: First episode less than 2 years.
2. Ligamentous Laxity: Children with general joint hypermobility.
3. Frequent Traction Activities: Continued swinging, pulling by arms.
4. Lack of Parental Education: Parents unaware of how to prevent re-injury.

Prevention Strategies (Parental Education)

DO:

• Lift child by the torso: Place hands under armpits, not by wrists/hands.
• Swing child safely: If swinging, support under armpits or around torso, not by hands/arms.
• Gentle handling: If pulling child away from danger, use gentle pressure or grab clothing/torso.

DON'T:

• Don't lift by hands/wrists: Avoid pulling child up from floor by hands.
• Don't swing by arms: Avoid "helicopter" or "airplane" games where child is swung by outstretched arms.
• Don't yank: Even if in a rush, avoid sudden jerking of arms.

Reassurance:

• Not Fragile: Child does not have a "weak" or damaged arm; it's a developmental issue that self-resolves.
• Normal Play: Child can play normally, climb, and be active without restrictions.
• Self-Limiting: Problem will resolve by school age (5-6 years).

What to Do if Recurrence Occurs

• Same Management: Reduction as per initial episode.
• Some Parents Learn Reduction: In children with very frequent recurrences, some clinicians teach parents to perform reduction at home (controversial; risk of missing fracture if parents apply to all limb pain).
• Orthopaedic Referral: Generally not required unless extremely frequent recurrences or concern for underlying hypermobility syndrome.

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9. Complications

Immediate Complications (Rare)

1. Failed Reduction

   • Incidence: 5-10% after first attempt (lower with hyperpronation).
   • Management: Alternative technique, repeated attempts, or expectant management with spontaneous reduction.

2. Iatrogenic Injury (Extremely Rare)

   • Radial Head Fracture: Theoretically possible with excessive force, but essentially never reported in literature.
   • Soft Tissue Injury: Bruising from forceful manipulation (very rare).

Short-Term Complications

3. Delayed Functional Recovery

   • Incidence: 5-10% of cases.
   • Presentation: Despite successful reduction (click felt), child continues to guard arm for several hours.
   • Cause: "Pain memory" or mild soft tissue irritation.
   • Management: Reassurance, observation, typically resolves within 24 hours.

4. Missed Fracture

   • Risk: If reduction attempted on fracture (e.g., undisplaced radial neck fracture misdiagnosed as pulled elbow).
   • Clue: Failed reduction after multiple attempts, or atypical history/examination.
   • Prevention: X-ray if red flags present.

Long-Term Complications (Very Rare)

5. Recurrent Subluxation

   • Incidence: 20-40% (as above).
   • Impact: Generally benign; no long-term sequelae.

6. Chronic Instability

   • Incidence: Exceptionally rare.
   • Presentation: Persistent ligamentous laxity beyond age 6.
   • Management: Specialist assessment; may be associated with generalized hypermobility syndrome.

7. Long-Term Functional Impairment

   • Incidence: None reported. Pulled elbow has excellent long-term prognosis with no documented cases of chronic pain, arthritis, or functional limitation.

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10. Prognosis

Immediate Outcome

• Success Rate: 85-95% success with first reduction attempt (higher with hyperpronation). [4,5]
• Pain Relief: Immediate relief after successful reduction.
• Functional Recovery: Full use of arm within 15 minutes in majority.

Short-Term Outcome

• Complete Recovery: > 99% of children have complete recovery within 24 hours.
• No Residual Effects: No pain, stiffness, or limitation of movement.

Long-Term Outcome

• Excellent: No long-term sequelae reported.
• Normal Development: No effect on growth, bone development, or future joint health.
• Self-Resolution: Ceases to occur by age 5-6 years due to radial head maturation.

Recurrence Prognosis

• 20-40% Recurrence Rate: Higher if first episode at young age.
• No Cumulative Damage: Multiple recurrences do not cause permanent ligament damage or instability beyond normal developmental timeline.

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11. Examination Focus (Viva Vault)

Opening Statement (Viva Scenario)

Examiner: "Tell me about pulled elbow."

Model Answer: "Pulled elbow, or radial head subluxation, is the most common elbow injury in toddlers aged 1-4 years. It occurs when sudden longitudinal traction on an extended, pronated forearm causes the annular ligament to slip proximally over the radial head and become entrapped in the radiocapitellar joint. Clinically, the child presents with pseudoparalysis—the arm held pronated and slightly flexed, refusing to use it, but with no swelling or deformity. It is a clinical diagnosis and is managed with closed reduction, most effectively using the hyperpronation technique, which has been shown in RCTs to have a higher first-attempt success rate than the traditional supination-flexion method."

High-Yield Viva Questions

Q1: What is the anatomical pathology of a pulled elbow?

A: "Axial traction causes the radial head to move distally relative to the capitellum. The annular ligament, which is relatively lax in young children, slips proximally over the convex dome of the radial head. When traction is released, the radius recoils proximally, but the ligament remains displaced and a portion becomes trapped—or interposed—between the radial head and the capitellum. This interposition prevents normal radiocapitellar articulation and causes pain with supination."

Q2: Why does it rarely occur after age 5?

A: "By age 5-6 years, the radial head undergoes morphological changes through progressive ossification. It develops a more bulbous, mushroom-shaped contour, becoming wider than the radial neck. This creates a mechanical block that prevents the annular ligament from slipping over the radial head, even with traction. Additionally, the ligament itself becomes thicker and has stronger bony attachments. These combined anatomical changes make subluxation biomechanically unlikely."

Q3: Describe your reduction technique.

A: "I would use the hyperpronation method as first-line, based on evidence from the Cochrane review showing superior success rates. I position the child comfortably, often on a parent's lap. I stabilize the elbow with one hand, placing my thumb over the radial head on the anterolateral aspect. With my other hand, I grasp the child's hand in a handshake position. I then firmly and rapidly pronate the forearm—turning the palm face down—while applying gentle extension to the elbow. I expect to feel a palpable click under my thumb as the ligament reduces. The child will cry briefly but should settle quickly. I then observe for 10-15 minutes and assess functional recovery by offering a toy or treat to encourage spontaneous use of the arm."

Q4: What is the "Popcorn Test"?

A: "The Popcorn Test is a functional assessment performed 10-15 minutes after reduction. The child is offered a desirable object—such as popcorn, a sweet, or a toy—that requires them to reach out, grasp, and supinate the forearm to bring it to their mouth. If the child spontaneously uses the affected arm without hesitation or pain, the reduction is confirmed successful. It's a practical way to demonstrate functional recovery and reassure parents."

Q5: When would you X-ray a child with suspected pulled elbow?

A: "Pulled elbow is a clinical diagnosis, and X-rays are not routinely required. However, I would obtain X-rays in the following circumstances:

• History of fall or direct trauma to the elbow, rather than pure traction
• Visible swelling, deformity, or bruising
• Significant localized bony tenderness
• Age outside the typical range—particularly over 5-6 years or under 6 months
• Failed reduction after 2-3 attempts, raising concern for an occult fracture such as an undisplaced radial neck or subtle lateral condyle fracture
• Any suspicion of non-accidental injury

The X-ray would be normal in true pulled elbow, as the annular ligament is a soft tissue structure not visible on plain radiographs."

Q6: What are the key differential diagnoses, and how do you distinguish them?

A: "The key differentials are fractures, particularly supracondylar and radial neck fractures, and septic arthritis.

• Supracondylar fracture: History of fall onto outstretched hand, significant swelling and deformity, severe pain, possible neurovascular compromise. This is the most important not to miss.

• Radial neck fracture: May also follow a fall, with focal swelling and tenderness over the proximal radius, and crepitus may be palpable.

• Septic arthritis: The child is systemically unwell with fever, the elbow is held in flexion with an effusion, there is severe pain on any movement, and inflammatory markers are raised.

Pulled elbow is distinguished by the classic traction mechanism, absence of swelling or deformity, and the characteristic protective posture with pronation. If there's any doubt, X-ray is indicated."

Q7: What advice would you give to parents to prevent recurrence?

A: "I would explain that pulled elbow occurs because the ligament in toddlers is relatively loose and the radial head hasn't fully developed yet. To prevent recurrence, they should avoid lifting the child by the hands or wrists—instead, they should lift from under the armpits or around the torso. They should also avoid swinging the child by the arms in games like 'helicopter' or 'airplane.' If they need to pull the child away from danger, they should do so gently or by grabbing clothing rather than yanking the arm. I would reassure them that this is a developmental issue, not a permanent weakness, and that it will resolve naturally by around age 5 when the radial head matures and becomes wider than the neck."

Q8: What is the evidence for hyperpronation vs. supination-flexion?

A: "Multiple randomized controlled trials and a Cochrane systematic review by Krul et al. in 2017 compared the two techniques. The review included over 900 children and found that hyperpronation had a first-attempt success rate of approximately 89%, compared to 77% for supination-flexion. Additionally, hyperpronation was associated with lower pain scores as assessed by parental and clinician observations. The initial landmark study was by Macias in 1998, which demonstrated a significant advantage for hyperpronation. Based on this level I evidence, current best practice is to use hyperpronation as the first-line reduction technique."

Q9: What would you do if reduction fails?

A: "If I don't feel a click or the child continues to refuse to use the arm after 15-20 minutes, I would:

1. First, allow more time—sometimes there is a 'pain memory' and the child needs up to 30 minutes to regain confidence.

2. Attempt a second reduction using the alternative technique—if I used hyperpronation first, I would try supination-flexion, or vice versa.

3. If still unsuccessful after 2-3 attempts, I would arrange X-rays to exclude an occult fracture, particularly an undisplaced radial neck fracture or a subtle lateral condyle fracture.

4. If the X-ray is normal, I would apply a broad arm sling for comfort and advise expectant management, as many cases reduce spontaneously within 24 hours with normal movement. I would provide clear safety-net advice to return if there's no improvement within 24-48 hours or if swelling develops.

5. If X-ray shows a fracture, I would manage accordingly with orthopaedic input if displaced."

Q10: Is there any role for ultrasound in diagnosis?

A: "While ultrasound can visualize the annular ligament and demonstrate its displacement over the radial head, as well as detect radiocapitellar joint effusion, it has no practical role in the acute diagnosis of pulled elbow. The diagnosis is clinical, and ultrasound is time-consuming, operator-dependent, and does not change management. Reduction should be attempted based on clinical grounds. Ultrasound might have a research or educational role but is not part of standard practice."

Common Examiner Follow-Up Questions

• "What if the parents insist on an X-ray?" → Explain ALARA principle, discuss that X-ray won't show the ligament and won't confirm diagnosis, but offer X-ray if significant parental anxiety or red flags.

• "Can you teach parents to reduce it at home?" → Controversial. Some advocate teaching parents of children with very frequent recurrences, but risk is that parents may attempt reduction on fractures or other pathology. Generally not recommended.

• "Why is the left arm more commonly affected?" → Because most parents are right-handed and therefore hold the child's left hand when walking or pulling.

• "What if there's bilateral presentation?" → Extremely rare; should raise suspicion for alternative diagnosis (systemic ligamentous laxity, metabolic bone disease) or non-accidental injury.

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12. Patient Explanation

What happened?

Your child has a condition commonly called "Nursemaid's Elbow" or "Pulled Elbow." It's a very common injury in toddlers. A small ligament—think of it like a rubber band—that holds one of the elbow bones in place has slipped over the bone and got stuck. It's like a jammed zipper.

Is it broken?

No, nothing is broken. It's not a fracture. The bone has just slipped slightly out of its normal position, and the ligament is trapped. It's a very minor injury, even though it looks scary when your child won't use their arm.

The Fix

I will do a quick movement to twist the arm gently. It will hurt for just one or two seconds, and your child will cry, but then the ligament will pop back into place. After about 10 minutes, the pain will disappear, and they will start using the arm normally again. Most children are back to playing within 15 minutes.

Can it happen again?

Yes, unfortunately, there's about a 20-30% chance it could happen again before your child turns 5. This is because the ligament is naturally loose in toddlers, and the elbow bone hasn't fully developed yet. The good news is that by around age 5, the bone grows wider and this problem stops happening.

How to prevent it

• Do: Lift your child by placing your hands under their armpits, not by their hands or wrists.
• Do: If you swing them, hold them around the body, not by the arms.
• Don't: Pull them up from the floor by their hands.
• Don't: Play games where you swing them by their outstretched arms.

When to come back

You should bring your child back if:

• They're not using the arm normally by tomorrow.
• You notice any swelling.
• They seem to be getting more upset or in more pain.

Otherwise, they're good to go and can play normally!

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13. References

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2. Schunk JE. Radial head subluxation: epidemiology and treatment of 87 episodes. Ann Emerg Med. 1990;19(9):1019-1023. doi:10.1016/s0196-0644(05)82569-3

3. Illingworth CM. Pulled elbow: a study of 100 patients. Br Med J. 1975;2(5972):672-674. doi:10.1136/bmj.2.5972.672

4. Macias CG, Bothner J, Wiebe R. A comparison of supination/flexion to hyperpronation in the reduction of radial head subluxations. Pediatrics. 1998;102(1):e10. doi:10.1542/peds.102.1.e10

5. Krul M, van der Wouden JC, Kruithof EJ, van Suijlekom-Smit LW, Koes BW. Manipulative interventions for reducing pulled elbow in young children. Cochrane Database Syst Rev. 2017;7(7):CD007759. doi:10.1002/14651858.CD007759.pub4

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15. Sacchetti A, Ramoska EE, Glascow C. Nonclassic history in children with radial head subluxations. J Emerg Med. 1990;8(2):151-153. doi:10.1016/0736-4679(90)90224-b

16. Hill JH, McGuire MH. Closed treatment of radial head subluxation in children. J Pediatr Orthop. 1990;10(3):402-405.

17. Newman J. "Nursemaid's elbow" in infants six months and under. J Emerg Med. 1985;2(6):403-404. doi:10.1016/0736-4679(85)90088-6

18. Kosuwon W, Mahaisavariya B, Saengnipanthkul S, et al. Ultrasonography of pulled elbow. J Bone Joint Surg Br. 1993;75(3):421-422. doi:10.1302/0301-620X.75B3.8496211

19. Bek D, Yildiz C, Köse O, Sehirlioğlu A, Başbozkurt M. Pronation versus supination maneuvers for the reduction of 'pulled elbow': a randomized clinical trial. Eur J Emerg Med. 2009;16(3):135-138. doi:10.1097/MEJ.0b013e32831097d1

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