THE CASE
A 4-year-old girl was triaged to the Pediatric Emergency Department (PED) Fast Track, complaining of pain and limited movement in both arms. For an unknown reason, she had attempted to lift a heavy, 3-person sofa several hours earlier.
Her prior medical history included left nursemaid elbow (NME) at both 15 months and 33 months of age. Neither event had a known mechanism of injury. In both episodes, it was noted in the medical record that the child was not using her arm, “was holding it funny,” and was complaining of pain. Each time, she presented about 24 hours after symptom onset.
During the physical exam in the PED, the patient showed no signs of acute distress. She held both arms close to her body, with a slight flexion at the elbows, and her hands were pronated. She could not pinpoint the location of her discomfort and described diffuse pain in her forearms, elbows, and upper arms. Examination revealed no localized pain or tenderness in her hands, wrists, or clavicles. Radial pulses were easily palpated, and capillary refill was less than 2 seconds. There was no swelling or bruising. The rest of her physical exam was normal.
DIAGNOSIS
The patient was given a diagnosis of self-inflicted bilateral nursemaid elbows (BNME). Reductions were performed by individually stabilizing the elbows and hyper-pronating the forearms, with palpable clicks felt at the proximal radius. Even though a palpable click was felt, this motion was immediately followed by supination of the forearm and flexion at the elbow. The patient tolerated the procedures well and was using both arms normally within 10 minutes. She was discharged home shortly thereafter.
DISCUSSION
BNME is an uncommon diagnosis; a literature review of reported cases indicates none were self-inflicted.1-4 However, NME is a common injury and is easily reduced. The classic mechanism of injury for NME involves the elbow in extension, while the forearm is pronated, and a sudden brisk axial traction is applied. This combination of motions causes the annular ligament to slip over the head of the radius and become displaced downward into the radiohumeral joint, where it becomes entrapped. In this case, the patient apparently exerted enough longitudinal traction while trying to lift the couch to produce the injury.
NME occurs most commonly in the left arm of girls between the ages of 4 months and 7 years and peaks at around the age of 2 years.5 A 2014 study by Irie et al6 corroborated the findings on left-side predominance and increased incidence with age, noting that frequency of injury peaked at 6 months in those younger than 1 year of age and at 2 years for those 1 year or older. However, the researchers found no significant sex difference.6
NME is radiographically indistinguishable from a healthy elbow.7 To prevent unnecessary expense and radiation exposure in young children, prereduction radiographs should only be used to rule out the possibility of fracture or other injury.7 Krul et al8 recommend restricting x-ray use to cases with an unclear history or those that are due to trauma other than an arm pull.
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