Pulled elbow is the term for subluxation of the radial head that affects children younger than 6 years, typically occurring due to a quick pull on a child’s arm. It is also called nursemaid elbow or babysitter’s elbow. It is an easily treatable condition.
The left arm is more commonly involved, presumably because most caretakers are right-handed. Girls tend to be affected more often than boys are. Patients with prior radial head fractures are at risk for progressive radial head subluxation.
The chance of recurrence is approximately 20-25%. Patients younger than two years have a higher risk of recurrence.
Relevant anatomy and Pathophysiology
[Read complete anatomy of elbow]
Annular ligament encircles and helps to stabilize the radial head. In children, this ligament is not completely fused and on traction, the radial head may slip or tear through the weak annular ligament into the radiocapitellar articulation.
This results in entrapment of the annular ligament and subluxation (or partial dislocation) of the radial head.
The oval shape of the proximal radius causes more acute angle posteriorly and laterally and leading to less resistance to slippage of the ligament when axial traction is applied to the extended and pronated forearm. This could be a contributory factor to the pulled elbow.
In children older than five years, the annular ligament is attached strongly. This reduces the chances of subluxation.
Generally, a pulled elbow is caused by brisk axial traction of the forearm, often by an adult who holds the child’s hand as the child pulls away. Falls, wrestling, and abuse are other causes. Infants have been reported with nursemaid elbow after rolling over or being assisted to roll over.
Axial traction is the most common cause of nursemaid elbow.
A fall is the second most common mechanism of injury. Few common examples are
- A child is held by his or her hand by an adult. The hand gets pulled as the child and adult lurch in opposite directions or adult tries to prevent a falling child
- A child is pulled up by the wrist.
- An arm is pulled through the sleeve of a sweater or coat.
Clinical Presentation
The usual presentation is a young child who suddenly refuses to use an arm after a pull on the wrist or hand. A clear history though is not available in all the cases.
The condition is usually unilateral.
Physical examination commonly reveals a forearm held in incomplete extension, and partially pronated.
Often, the weight of the affected arm is supported with the other hand.
Tenderness at the head of the radius may be present. Because of pain, the patient resists supination/pronation as well as flexion/extension of the forearm.
No significant edema or effusion is be seen on examination. Any focal swelling or other areas of tenderness should alert the clinician for the presence of other injuries.
Imaging Studies
X-rays
X-rays are almost normal in the pulled elbow as the transposed angular ligament between radial head and capitellum does not cause recognizable widening of the radiocapitellar joint.
Therefore radiography is not done routinely if there is certainty of clinical diagnosis.
However, uncertain diagnosis or failure of reduction after clinical diagnosis warrants x-ray of the extremity.
Ultrasonography
Ultrasonography shows increased radiocapitellar distance, representing annular ligament entrapment prior to manipulation. J-shaped hypoechoic supinator muscle [Hook sign ] above the radial head has also been described.
Ultrasound can distinguish between the pulled elbow and other injuries as well.
But its usefulness in acute settings is controversial.
MRI
MRI can be used to confirm subluxation with a ligament tear but is often not required.
Differential Diagnoses
- Elbow Fracture
- Soft Tissue Hand Injury
- Wrist Fracture
Treatment of Pulled Elbow
Radial head subluxation is managed by means of manual reduction. Either of the following two reduction methods may be used:
- Supination-flexion technique
- Hyperpronation/forced pronation technique
If one technique fails initially, the other may be attempted.
During radial head reduction, the patient stands or sits on the caregiver’s lap for comfort and support. The physician faces the patient and sits or kneels to be at the same eye level.
Supination-Flexion Technique of Reduction of Pulled Elbow
The supination-flexion technique is the classic method. It has a success rate of 80-92%.
- With the patient’s arm in pronation and elbow in 90° of flexion, the pressure applied over the patient’s radial head.
- Next, the wrist is firmly supinated, with pressure maintained on the radial head.
- The patient’s elbow is then completely flexed.
- A click is often felt or heard over the radial head on full flexion and is associated with a high probability of successful reduction.
Hyperpronation/Forced Pronation Technique of Reduction of Pulled Elbow
- With the patient’s elbow is held in 90° of flexion, the wrist is firmly hyperpronated. [Some advocate extension position to begin with and then flex the elbow]
- A palpable or audible click is associated with a high probability of successful reduction.
Hyperpronation technique has been associated with fewer failures than other technique and suggested be less painful.
Some authors consider it to be preferred reduction maneuver.
Combination of the two techniques (hyperpronation followed by supination) has also been proposed.
Care After Reduction
Once the radial head has been reduced, the child’s pain and apprehension often immediately resolve. [Though in practice I have found that child may cry for sometime, probably due to pain and stress associated with reduction.]
The child should be evaluated after 10-15 minutes.
Most children begin to use the affected arm immediately, though some may take as long as 30 minutes especially when the subluxation has been present for more than 12 hours.
An unsuccessful reduction warrants another attempt at reduction. But repeated failure should lead to consideration of alternate diagnosis.
No other measure is required after the elbow has been reduced. The child is allowed to use the limb and in some cases, the sling may be provided.
Prevention
Because redial head subluxation tends to recur, parents/caregivers should be taught not to pull children by their arms
Prognosis
Prognosis is excellent. No permanent injury results.
For those who have had one occurrence, the chance of recurrence is approximately 20-25%. Those 24 months and younger may have the greatest risk of recurrence.
References
- Eismann EA, Cosco ED, Wall EJ. Absence of Radiographic Abnormalities in Nursemaid’s Elbow. J Pediatr Orthop. 2014. 34(4):426-31.
- Vitello S, Dvorkin R, Sattler S, Levy D, Ung L. Epidemiology of Nursemaid’s Elbow. West J Emerg Med. 2014 Jul. 15 (4):554-7.
- Dohi, D. Confirmed specific ultrasonographic findings of pulled elbow. J Pediatr Orthop. 2013 Dec. 33(8):829-31.
- Toupin P, Osmond MH, Correll R, Plint A. Radial head subluxation: how long do children wait in the emergency department before reduction?. CJEM. 2007 Sep. 9(5):333-7.
- Quan L, Marcuse EK. The epidemiology and treatment of radial head subluxation. Am J Dis Child. 1985 Dec. 139(12):1194-7.
- McDonald J, Whitelaw C, Goldsmith LJ. Radial head subluxation: comparing two methods of reduction. Acad Emerg Med. 1999 Jul. 6(7):715-8.
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