Nursemaid elbow, also known as “radial head subluxation” or simply “pulled elbow”, is the most common upper-limb injury in children under the age of 6.[1, 33] It is typically an easily treatable condition. Correct diagnosis is the primary challenge to the physician.
The etiology is movement of the head of the radius under the annular ligament. The distal attachment of the annular ligament covering the radial head is weaker in children than in adults, allowing it to be more easily torn. As children age, the annular ligament strengthens. In children over the age of 5, subluxation of the radial head is prevented by a thicker and stronger attachment between the annular ligament and the periosteum of the radial neck.[2] As a result, nursemaid’s elbow occurs less often.
A Nursemaid’s Elbow (NE) is a low-energy trauma often occurring from brisk axial traction of the forearm, often by an adult who holds the child’s hand as the child pulls away. Other causes of injury include falls, wrestling, and abuse.[3]
The oval shape of the proximal radius in cross-section contributes to this condition by offering a more acute angle posteriorly and laterally, with less resistance to slippage of the ligament when axial traction is applied to the extended and pronated forearm. The common belief that nursemaid elbow is due to children having a radial head smaller than the radial neck is incorrect.
Published case series report a slight predominance in females.[4, 5]
Published case series report a slight left arm predominance in both males and females.[4, 5]
A study by Wong et al that reviewed 246 pediatric ED visits for radial head subluxation reported that recurrence was more likely in male patients.[6]
Nursemaid elbow most commonly occurs in children aged 1-4 years. However, it has been reported in patients as young as 4 months and as old as 31 years.[7]
A study that examined the epidemiological description of radial head subluxation found that the average age of children presenting with nursemaid's elbow was 28.6 months.[5]
The prognosis is excellent. Parents can be reassured that no permanent injury results from this condition.
For those who have had one occurrence, the chance of recurrence is approximately 20-25%.[4, 8] Those 24 months and younger may have the greatest risk of recurrence.[8]
Most parents appreciate knowing that reoccurrence can occur in 1/5-1/4 of patients.
Patient history usually leads to a presumptive diagnosis.
Parents often give a history of a young child with no history of trauma who suddenly refuses to use an arm.
A history of axial traction by a pull on the hand or wrist may be elicited but often is not volunteered.
Common scenarios include the following:
The condition is usually unilateral. However, bilateral cases have been reported.[9]
Physical examination commonly reveals an anxious child who is protective of the affected arm. In most children, anxiety is greater than pain.
The forearm is usually held in incomplete extension, and the forearm is partially pronated.
Often, the weight of the affected arm is supported with the other hand.
Notably, erythema, warmth, edema, or signs of trauma are absent.
Distal circulation, sensation, and motor activity are normal.
A reluctance to move digits or the wrist is common, perhaps from fear of eliciting pain in the elbow.
Tenderness at the head of the radius may be present. The patient resists supination/pronation as well as flexion/extension of the forearm.
Axial traction is the most common cause of nursemaid elbow.
A fall is the second most common mechanism of injury.
Infants have been reported with nursemaid elbow after rolling over or being assisted to roll over.
The primary challenge is to arrive at the correct diagnosis without overlooking other causes of the patient's symptoms.
In nursemaid’s elbow, the annular ligament becomes transiently interposed between the radial head and capitellum, but does not cause recognizable widening of the radiocapitellar joint. Nursemaid’s elbows are often indistinguishable from healthy elbows on radiograph.[3] However, if history and/or physical exam reveal concerns for possible fracture, radiography may be warranted.
If manipulation is unsuccessful and a review of the history and physical examination supports nursemaid elbow as the likely diagnosis, another attempt at reduction may be performed using the same method. If reduction is again unsuccessful, a third attempt using the alternative technique may be utilized. If a third attempt at reduction fails, radiography of the extremity is warranted to look for fracture (if not already done).
Ultrasonography has been used as a noninvasive modality to evaluate annular ligament injury. Published reports describe increased radiocapitellar distance, representing annular ligament entrapment prior to manipulation.[10, 11] Other ultrasound findings include a “J-shaped” hypoechoic supinator muscle, or “Hook” sign above the radial head.[12, 13] It should be noted that ultrasound can also be used to assess for fractures. An enlarged posterior fat pad or lipohemarthrosis in the olecranon fossa are findings associated with fracture.[14] A negative ultrasound may reduce the need for radiographs in children with elbow injuries.[15]
Although ultrasonography can confirm a nursemaid’s elbow, and evidence for its accuracy are emerging, utility in the acute setting is the subject of continued investigation.[16, 17]
For additional information, see Elbow Trauma, Pediatric and Elbow, MRI.
Imaging studies are useful in ruling out possible fracture but are often unnecessary.
If manipulation is unsuccessful and a review of the history and physical examination supports nursemaid elbow as the likely diagnosis, another attempt at reduction is warranted.
If reduction is unsuccessful after 2-3 attempts, radiography of the extremity is warranted.
Ultrasonography has been used as a noninvasive modality to assess for annular ligamentous injury and displacement of the radial head from the capitellum. It has also been used to assess progress of treatment for patients with recurrent subluxations. Usefulness in the acute setting is the subject of continued investigation.[16, 17, 18]
MRI can be used to confirm subluxation with a ligament tear.[16]
For additional information, see Elbow Trauma, Pediatric and Elbow, MRI.
"First do no harm" is a useful precept for prehospital care. Assume that a fracture is present. Taking appropriate precautions to immobilize and protect the extremity is usually wise.
"First do no harm" is also a useful precept to follow in the ED.
Because normal function can be quickly restored in the ED, this can be a gratifying condition for the physician to treat.
Treatment consists of manipulating the child's arm (closed reduction) so that the annular ligament and radial head return to their normal anatomic positions. Traditionally, the manipulation consists of forearm supination and elbow flexion, as follows:
A click noted by the examiner has a positive predictive value of more than 90% in 2 published case series[19] and a negative predictive value of 76% in one case series.[4]
Some authors believe the likelihood of successful reduction is increased if pressure is applied over the radial head.
Reports describe successful closed reduction using forearm hyper-pronation (HP) instead of supination-flexion (SF) Pronation may be more effective and/or less painful than supination manipulation.[20, 21, 22, 23, 33] A recent prospective, pseudorandomized, controlled non-blinded study compared the efficacy and pain associated with HP and SF reduction techniques. Successful reduction was accomplished on first attempt in 121(80.7%) of cases, with 56 of 82(68.3%) using the SF technique and 65 of 68 (95.6%) using the HP technique (P< 0.001). However, pain levels of both techniques were not statistically different.[24] The findings are corroborated by two other randomized, prospective studies that found significantly higher rates of first-attempt success with the HP technique.[25, 26]
Videos are available online showing both forearm SF and HP techniques.[27, 28] A quick overview of the disorder and the reduction maneuvers is also available for free through the NEJM website.[29]
A 2012 Cochrane Collaboration review noted that the total number of patients assessed in all of these studies was small. Furthermore, all studies were at high risk for assessor bias due to lack of blinding of the assessors. One study was assessed to be at high risk for selection bias. The conclusion was that evidence is limited for low-quality clinical trials and further study is warranted.[30]
If manipulating the elbow produces a click, the child should be observed in the ED. Many references report immediate return of function, but often the child will not use the arm normally for 15-30 minutes.
If radiographic findings reveal no fracture and the child continues to refuse to use the arm normally, another attempt at reduction (ideally, by a different health professional, if available) is reasonable. Given that intra-operator variability is not always reported and one may become comfortable with one technique or the other, it is reasonable to make first and second attempts at reduction with either method.
Age younger than 2 years and a delay of more than 4 hours before treatment have been associated with failure to use an affected arm within 30 minutes.
If manipulating the elbow produces a click, the child should be observed in the ED. Many references report immediate return of function, but often the child will not use the arm normally for 15-30 minutes.
Postreduction films are not necessary.
An important part of the management is educating parents about the risk of reoccurrence.
If radiographic findings demonstrate no fracture, repeat attempts at reduction are unsuccessful, and the child does not regain normal function after 30-40 minutes, the safest management is to support the arm in a sling (or splint and sling) and have the child reevaluated by a physician (usually a primary care physician, not an orthopedist) in 1-2 days. One case series reported 7 patients meeting these criteria had either spontaneous return of function or successful reduction at follow-up evaluation by day 4.
Once reduced, pain abates, and further therapy is unnecessary. Persistent pain is inconsistent with nursemaid elbow and should lead one to reconsider the diagnosis.
Because nursemaid elbow tends to reoccur, families benefit from counseling. Avoidance of future axial traction should minimize risk of reoccurrence.
Prognosis is excellent. Parents can be reassured that no permanent injury results from this condition.
For those who have had one occurrence, the chance of recurrence is approximately 20-25%.[4, 8] Those 24 months and younger may have the greatest risk of recurrence.[8]