- Clinical science
Radial head subluxation (also “pulled elbow” or “nursemaid's elbow”) refers to the partial dislocation of the head of the radius at the level of the radio-humeral joint. The injury most commonly occurs in young children after sudden tugging of the outstretched and pronated arm (e.g., adults suddenly pulling a child's arm to keep it from falling). Clinical signs include painful and limited movement of the upper extremity and guarding, with the arm held in a flexed and pronated position. The diagnosis is often made based on typical symptoms and therefore x-ray imaging is generally not required. Management is usually conservative and involves closed, manual reduction of the radial head. The reduction can be carried out in an outpatient setting and does not require any immobilization of the elbow or further surgical treatment.
- Subluxation of the radial head through the annular ligament: The annular ligament is interposed and entrapped in the radiocapitellar joint.
- Radial head subluxation is the most common elbow injury in children under 5 years of age and occurs exclusively in this age group.
- Age: 1–5 years, peak incidence between two and three years.
- Sex: ♀ > ♂
- Risk factors
Epidemiological data refers to the US, unless otherwise specified.
Traumatic (most common)
- Sudden axial traction of the pronated and extended forearm
- Typical activities: adult quickly pulls up a falling child by the hand; , swings a child by the hands, or drags a child by the arm
- Congenital structural abnormalities (e.g., collagen abnormalities, abnormal endochondral ossification of the growth plate and ossification sites external to the joint)
- Child holds the arm, with the elbow slightly flexed and pronated
- Pain, aggravated by movement
- Limited extension and flexion
- No swelling
- History and findings may be atypical, especially with children < 3 years old, who may be unable to properly articulate their symptoms or the circumstances of the injury
The condition is predominantly clinically diagnosed, with a limited role for imaging. A successfully executed closed manual reduction is not just therapeutic, but also diagnostic (see “Therapy” below).
- Not necessary, if the patient presents with typical history and clinical signs.
- May be useful in atypical or irreducible cases to identify a displacement of the radiocapitellar line without further disruption of the radiocapitellar joint
- Ultrasound: may be considered to prevent misdiagnosis and delayed treatment in children too young to properly articulate their symptoms,
- Epidemiology: occurs more commonly in adults than radial head dislocation or subluxation
- Clinical presentation
- Diagnostic: Elbow x-ray in two planes may show typical “fat pad sign”
- Complication: incorrect reduction can lead to cubitus valgus
The differential diagnoses listed here are not exhaustive.
While applying pressure to the radial head, the following maneuvers are carried out:
- Supination of the forearm with the elbow in slight flexion
- Hyperpronation of the forearm
- In successful reduction, a “click” might be heard
- Post-reduction: clinical control of normal range of motion of the elbow
- A second attempt at reduction may be necessary (by using the same or a different approach), if normal range of motion is not achieved
- Immobilization of the arm is not required. Most children regain full mobility of the elbow in a short time (10-30 minutes post reduction).
- While applying pressure to the radial head, the following maneuvers are carried out:
- Surgery: only indicated when closed manipulative reduction is unsuccessful
- Prevention: parents and caretakers should be educated about the most common mechanisms of injury to prevent recurrence