Radial head subluxation

Background

Anterior capsule of elbow-joint. Nursemaid's elbow involves the head of radius slipping out from the anular ligament of radius.

Medical illustration showing the displaced angular ligament with elbow subluxation.

Common radial head subluxation mechanisms of injury.

• Also known as "Nursemaid's elbow" an "pulled elbow"
• Radial head subluxation due to longitudinal traction on arm
  • Annular ligament of radius displaces into radiocapitellar articulation
• Age 1y-5y (peak 2y-3y)
  • After this point, the change in shape of the radial head with growth protects against subluxation

Clinical Features

History

• Typical history includes sudden longitudinal traction on the arm
  • Swinging child by arms by playing
  • Pulling child back from walking into traffic
  • Catching child who is falling
• Younger children may sustain the injury by less classic mechanisms
• Sudden onset of pain

Physical

• Refusal to use the affected arm
• Arm held in extension
• Refusal to supinate
• Non-tender to palpation
• Limited edema
• No bruising

Differential Diagnosis

Elbow Diagnoses

Radiograph-Positive

• Distal humerus fracture
• Radial head fracture
  • Essex-Lopresti fracture
• Capitellum fracture
• Olecranon fracture
• Elbow dislocation

Radiograph-Negative

• Biceps tendon rupture/dislocation
• Lateral epicondylitis
• Medial epicondylitis
• Olecranon bursitis (nonseptic)
• Pronator teres syndrome
• Septic bursitis

Pediatric

• Nursemaid's elbow
• Supracondylar fracture
• Lateral epicondyle fracture
• Medial epicondyle fracture
• Olecranon fracture
• Radial head fracture
• Salter-Harris fractures

Evaluation

• Clinical diagnosis
  • Patients with classic story (toddler 1-3 years old, low energy mechanism) and findings (no bruising/swelling, no point tenderness, arm held adducted/pronated) do not require imaging before reduction
  • Any child with an unclear story or unsuccessful reduction should undergo imaging to rule other pathology
• Assess neurovascular status prior to (and following) reduction

Management

Hyperpronation (A) and supination (B) techniques. These techniques may also be combined in practice.

Reduction

Hyperpronation has greater first attempt success (94% vs 69%), but both have similar overall reduction rate; consider doing both techniques at once in quick succession

• Hyperpronation Technique
  • Hold patient's elbow at 90 degrees with one hand
    • Place thumb over radial head to facilitate reduction and provide tactile feedback
  • With other hand hyperpronate patient's wrist
• Supination Technique
  • Hold patient's elbow at 90 degrees with one hand
    • Place thumb over radial head to facilitate reduction and provide tactile feedback
  • With other hand supinate patient's wrist and fully flex elbow

Post-Reduction

• If successful, patient will have return of full range of motion within 30min
  • Usually child with begin to spontaneously use the affected arm
  • If child is not using affected arm, may try offering a popsicle or toy and encouraging to reach with affected arm
• If unsuccessful after multiple attempts, obtain x-ray and consider alternative diagnoses (e.g. Salter-Harris fracture)

Disposition

• Discharge home after successful reduction
• No immobilization
• Caution caregivers to avoid longitudinal traction on arm
• Advise caregivers that injury is frequently recurrent until radial head maturity

See Also

• Elbow diagnoses

External Links

• Merk Manual: How To Reduce a Radial Head Subluxation (Nursemaid's Elbow)