Pediatric Annals

Special Issue Article 

Elbow Pain After a Fall: Nursemaid's Elbow or Fracture?

Anna Cohen-Rosenblum, MD; Robert J. Bielski, MD

Abstract

Nursemaid's elbow and elbow fractures are both common causes of acute elbow pain, but the mechanism of injury is quite different. In children, falls frequently go unwitnessed and children are often inaccurate when recounting the sequences of a fall, making the mechanism difficult to ascertain. A common clinical mistake is to treat all elbow injuries as a nursemaid's elbow. When the mechanism of injury is unknown, radiographs should be used to help make the diagnosis. Occult fractures, also known as “hairline” elbow fractures, may not be visible on initial X-rays, but clues to the diagnosis, especially the posterior fat pad, can be helpful in evaluation. When an occult fracture is suspected based on history and radiographic findings, the patient's elbow should be immobilized, not manipulated. This article also reviews successful reduction maneuvers for nursemaid's elbow. [Pediatr Ann. 2016;45(6):e214–e217.]

Abstract

Nursemaid's elbow and elbow fractures are both common causes of acute elbow pain, but the mechanism of injury is quite different. In children, falls frequently go unwitnessed and children are often inaccurate when recounting the sequences of a fall, making the mechanism difficult to ascertain. A common clinical mistake is to treat all elbow injuries as a nursemaid's elbow. When the mechanism of injury is unknown, radiographs should be used to help make the diagnosis. Occult fractures, also known as “hairline” elbow fractures, may not be visible on initial X-rays, but clues to the diagnosis, especially the posterior fat pad, can be helpful in evaluation. When an occult fracture is suspected based on history and radiographic findings, the patient's elbow should be immobilized, not manipulated. This article also reviews successful reduction maneuvers for nursemaid's elbow. [Pediatr Ann. 2016;45(6):e214–e217.]

Elbow pain after a fall is commonly seen both in the emergency department (ED) and in a primary care setting. It is important to obtain elbow imaging before attempting any manipulation of the extremity. In the case of an occult fracture misdiagnosed as a nursemaid's elbow, manipulation can be harmful.

Illustrative Case

A 3-year-old girl with no significant past medical history presented to the ED with refusal to move her left arm after falling on the playground that afternoon. Her father had witnessed the fall, and reported that the patient jumped off a 3-foot high piece of playground equipment onto her outstretched left hand. Physical examination revealed mild swelling with tenderness to palpation diffusely about the elbow. The skin was intact with no ecchymosis. The patient did not cooperate with a complete neurologic examination, but she was observed to move all digits on the left hand when distracted and had no apparent tenderness to palpation about the left shoulder, forearm, wrist, or hand. She had a palpable left radial pulse, and capillary refill was less than 2 seconds in all digits of the left hand. X-ray imaging of the left elbow, forearm, and wrist were obtained. The lateral view of the left elbow (Figure 1) showed no evidence of fracture or dislocation but was remarkable for a large posterior fat pad.


            Lateral elbow radiograph from the day of injury showing a prominent posterior fat pad (red arrows).

Figure 1.

Lateral elbow radiograph from the day of injury showing a prominent posterior fat pad (red arrows).

The patient was diagnosed with a likely occult elbow fracture, placed in a long-arm fiberglass cast, which was bivalved (cut longitudinally on both sides of the cast to allow for swelling), and outpatient follow-up procedures were arranged with a pediatric orthopedic surgeon for 1 to 2 weeks later for repeat imaging and examination.

Further imaging of the left elbow taken on her first follow-up visit (Figure 2) revealed periosteal reaction about the distal humerus indicating a healing supracondylar fracture. At 3.5 weeks after the injury, the cast was removed and repeat radiographs obtained that confirmed the diagnosis of a nondisplaced distal humerus supracondylar fracture (Figure 3). The cast was removed at that time, and the patient was allowed to move her elbow freely. She went on to heal uneventfully.


            Imaging taken approximately 2 weeks postinjury shows subtle periosteal reaction of the distal humerus. This indicates healing of the nondisplaced distal humerus supracondylar fracture (red arrow), which is obscured by cast material.

Figure 2.

Imaging taken approximately 2 weeks postinjury shows subtle periosteal reaction of the distal humerus. This indicates healing of the nondisplaced distal humerus supracondylar fracture (red arrow), which is obscured by cast material.


            Imaging taken approximately 6 weeks postinjury of a different patient (out of cast) that clearly shows distal humerus periosteal reaction (red arrows), confirming the diagnosis of a nondisplaced distal humerus supracondylar fracture.

Figure 3.

Imaging taken approximately 6 weeks postinjury of a different patient (out of cast) that clearly shows distal humerus periosteal reaction (red arrows), confirming the diagnosis of a nondisplaced distal humerus supracondylar fracture.

Discussion

The illustrative case is a typical presentation of pediatric elbow pain, resulting from an occult elbow fracture. Usually the mechanism is a fall onto an outstretched hand, but often the cause is unknown and/or the fall unwitnessed by a supervising adult. Even if the fall is witnessed by an adult, the parent or caregiver may falsely believe that the elbow cannot be broken because there was no direct blow to the elbow. It is important for physicians to be aware that 90% to 98% of supracondylar elbow fractures result from a fall onto an outstretched hand rather than directly onto the elbow.1 As the elbow hyperextends, the olecranon drives into the olecranon fossa, causing the anterior cortex of the distal humerus to fail, creating the fracture.2

Physical examination in these patients may be nonspecific with diffuse elbow pain and swelling, and may be confused with “nursemaid's elbow” or subluxation of the radial head, which can present in a similar manner but is caused by quite a different mechanism.3 The latter patients typically present with elbow pain after a traction injury to the elbow in extension and pronation, ie, sudden pulling of the elbow by an adult or older child while they are falling or being suddenly picked up by the arm.4

The pathology behind nursemaid's elbow has been debated for decades, but recent biomechanical studies have found that the injury most likely results from entrapment of the annular ligament between the subluxed radial head and the radiocapitellar joint.4 Radiographs of a patient with nursemaid's elbow are typically normal.5 Reduction of a true nursemaid's elbow is easily performed without sedation or other analgesia and can be obtained by hyperpronation of the forearm with the elbow flexed at 70 to 90 degrees, or by supinating the affected forearm while simultaneously flexing the elbow well past 90 degrees and exerting gentle pressure over the radial head.6 Although both methods are well-described in the literature, a 2014 prospective randomized trial of 115 children found that the hyperpronation method led to a statistically significant increase in successful reduction compared with the supination method.6 These findings were echoed in a 2012 Cochrane Review of nursemaid's elbow reduction techniques that also found the pronation technique to have a statistically significant decrease in failure rate compared to supination.7

It is important for the clinician to obtain a thorough history prior to attempting reduction of a presumed nursemaid's elbow, because any manipulation of a missed elbow fracture (regardless of method) can be potentially harmful both by displacing the fracture and causing a delay in definitive treatment. A study by Kraus et al.3 found 11 children who, over a 6-month period from a single center, were initially thought to have radial head subluxation based on clinical diagnosis only, then treated with one or more reduction attempts, and were eventually diagnosed with elbow fractures. When the mechanism of injury is in doubt, radiographs should be obtained.

Radiographic imaging of occult pediatric elbow fractures will show no acute osseous abnormalities; often the only abnormal finding will be the so-called “posterior fat pad sign,” a lucent area over the posterior cortex of the distal humerus seen on lateral views of the elbow only in the presence of an effusion. The elbow effusion elevates the fat pad off the distal humerus making it visible on radiographs.8 As a nonspecific indicator of elbow joint effusion, a visible posterior fat pad can indicate a variety of occult pediatric elbow fractures. These include supracondylar fractures of the distal humerus (most common), olecranon fractures (Figure 4), lateral condyle fractures, and radial neck fractures.8,9 The exact site of an occult pediatric elbow fracture would be revealed on follow-up radiographs based on the location of any periosteal reaction or the appearance of further fracture displacement.


            Left elbow of an 8-year-old child with posterior fat pad sign (red arrow) as well as an olecranon fracture (yellow arrows).

Figure 4.

Left elbow of an 8-year-old child with posterior fat pad sign (red arrow) as well as an olecranon fracture (yellow arrows).

It should be noted that the radiographic presence of an isolated anterior fat pad (a lucent triangle on the anterior cortex of the distal humerus) is a normal finding and usually not associated with fracture10 (Figure 5). When a posterior fat pad is encountered on imaging without any other radiographic abnormalities in the clinical context of pain and an acute injury, a clinician should be highly suspicious for occult fracture of the elbow. A classic 1999 study by Skaggs and Mirzayan8 showed that 76% of 45 children with a history of trauma to the elbow, posterior fat pad indications, and no other radiographic evidence of fracture on initial presentation were later found to have an occult elbow fracture.


            Elbow imaging of a child, who did not have a fracture, with normal finding of an anterior pad (red arrow).

Figure 5.

Elbow imaging of a child, who did not have a fracture, with normal finding of an anterior pad (red arrow).

It is not unusual for patients with a nondisplaced elbow fracture or a nursemaid's elbow to initially present to the primary care office. Recognition of the posterior fat pad is therefore an important step in the proper treatment of these injuries. If the patient is incorrectly diagnosed with nursemaid's elbow or soft tissue injury, the occult elbow fracture may not be appropriately immobilized. If the patient falls again, this benign, nondisplaced fracture may become displaced, often requiring surgical intervention. In addition, a 2014 review5 of the elbow radiographs of 27 children with nursemaid's elbow compared with matched controls found that none of the images showed a visible posterior fat pad. This reinforces the point that patients with elbow pain without the typical history of abrupt longitudinal traction should undergo elbow imaging prior to any reduction attempts.

Conclusion

It is imperative that all patients with elbow pain after an acute injury and radiographic findings of an isolated posterior fat pad be immobilized in a long-arm cast or splint, and sent for a follow-up examination with a pediatric orthopedic surgeon within 1 to 2 weeks for repeat imaging to evaluate for any interim fracture displacement or periosteal reaction. Table 1 outlines the differential diagnosis and emergent treatment for children with acute elbow pain. Reduction attempts for suspected radial head subluxation without prior imaging should be avoided in children with elbow pain who do not have the typical history of abrupt traction to the arm by an adult or older child. Additionally, it is possible that patients with these injuries will present to an outpatient setting rather than the ED; therefore, it is important that the primary care provider be well-informed regarding the appropriate diagnostic plan for acute elbow pain and know when pediatric orthopedic referral and/or emergent evaluation is necessary.11


            Differential Diagnosis for Pediatric Elbow Pain After Acute Injury Without Osseous Abnormalities on Imaging

Table 1:

Differential Diagnosis for Pediatric Elbow Pain After Acute Injury Without Osseous Abnormalities on Imaging

References

  1. Otsuka NY, Kasser JR. Supracondylar fractures of the humerus in children. J Am Acad Orthop Surg. 1997;5:19–26. doi:10.5435/00124635-199701000-00003 [CrossRef]
  2. Barr LV. Paediatric supracondylar humeral fractures: epidemiology, mechanisms and incidence during school holidays. J Child Orthop. 2014;8:167–170. doi:10.1007/s11832-014-0577-0 [CrossRef]
  3. Kraus R, Dongowski N, Szalay G, Schnettler R. Missed elbow fractures misdiagnosed as radial head subluxations. Acta Orthop Belg. 2010;76:312–315.
  4. Diab H, Hamed MM, Allam Y. Obscure pathology of pulled elbow: dynamic high-resolution ultrasound-assisted classification. J Child Orthop. 2010;4:539–543. doi:10.1007/s11832-010-0298-y [CrossRef]
  5. Eismann E, Cosco E, Wall E. Absence of radiographic abnormalities in nursemaid's elbows. J Pediatr Orthop. 2014;34:426–431. doi:10.1097/BPO.0000000000000126 [CrossRef]
  6. García-Mata S, Hidalgo-Ovejero A. Efficacy of reduction maneuvers for “pulled elbow” in children: a prospective study of 115 cases. J Pediatr Orthop. 2014;34(4):432–436. doi:10.1097/BPO.0000000000000130 [CrossRef]
  7. Krul M, van der Wouden JC, van Suijlekom-Smit LW, Koes BW. Manipulative interventions for reducing pulled elbow in young children. Cochrane Database Syst Rev. 2012;1: CD007759.
  8. Skaggs D, Mirzayan R. The posterior fat pad sign in association with occult fracture of the elbow in children. J Bone Joint Surg Am. 1999;81(10):1429–1433.
  9. Skaggs D. Elbow fractures in children: diagnosis and management. J Am Acad Orthop Surg. 1997;5:303–312. doi:10.5435/00124635-199711000-00002 [CrossRef]
  10. Blumberg S, Kunkov S, Crain EF, Goldman HS. The predictive value of a normal radiographic anterior fat pad sign following elbow trauma in children. Pediatr Emerg Care. 2011;27:596–660. doi:10.1097/PEC.0b013e318222553b [CrossRef]
  11. Shaw J, O'Connor F. Elbow injuries. In: Birrer R, Griesemer B, Cataletto M, eds. Pediatric Sports Medicine for Primary Care. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:350–366.

Differential Diagnosis for Pediatric Elbow Pain After Acute Injury Without Osseous Abnormalities on Imaging

Fracture Type Posterior Fat Pad Sign Most Common Mechanism Treatment in Emergency Department
Supracondylar fracture (occult) Present Fall onto outstretched hand Long-arm cast or splint
Lateral condyle fracture (occult) Present Fall onto outstretched hand with varus stress to elbow Long-arm cast or splint
Olecranon fracture (occult) Present Fall onto outstretched hand with elbow in flexion Long-arm cast or splint
Radial neck fracture (occult) Present Fall onto outstretched hand with forearm in supination Long-arm cast or splint
Nursemaid's elbow Absent Abrupt traction with elbow extended and forearm in pronation Reduction maneuver
Soft tissue contusion Absent Direct trauma Sling immobilization for comfort
Authors

Anna Cohen-Rosenblum, MD, is a Resident, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center. Robert J. Bielski, MD, is an Associate Professor, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center; and an Attending Pediatric Orthopedic Surgeon, The University of Chicago Medicine Comer Children's Hospital.

Address correspondence to Robert J. Bielski, MD, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637; email: rbielski@uchicago.edu.

Disclosures: The authors have no relevant financial disclosures to disclose.

10.3928/00904481-20160506-01

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