Current Approach to the Management of Forearm and Elbow Dislocations in Children

CME REVIEW ARTICLE

Michael Gottlieb, MD, RDMS and Linda I. Suleiman, MD

RADIAL HEAD SUBLUXATIONS Abstract: Pediatric orthopedic injuries are a common reason for presentation to the emergency department. This article sequentially discusses 2 important upper extremity injuries that require prompt management in Background the emergency department. Radial head subluxations are discussed with a Radial head subluxation, also referred to as “nursemaid's el- focus on current evidence for imaging, reduction techniques, and follow- bow” or “pulled elbow” is the most common orthopedic injury 1 up. Elbow dislocations, although less common than radial head subluxa- among children under the age of 6 years. One study demonstrated tions, are also addressed, highlighting imaging, reduction, immobilization, an overall incidence of 1.2% per year among children aged 0 to 2 and follow-up recommendations. 5 years. In the United States, the incidence of emergency care visits for radial head subluxation has been reported to be 2.7 to 5.0 per Key Words: forearm, elbow, dislocation, reduction, nursemaid's, 1000 children aged 0 to 18 years.3,4 pulled elbow It occurs most commonly in toddlers with a peak incidence – (Pediatr Emer Care 2019;35: 293–300) between 2 to 3 years of age.4 12 However, it can occur in patients as young as 22 days and as old as 16 years.10,13 Studies suggest that it is significantly more common in girls than boys.4–12,14 TARGET AUDIENCE This CME activity is intended for practitioners who care for pediatric patients presenting with forearm or elbow dislocations, Anatomy and Pathophysiology which may include general pediatricians, pediatric emergency Although multiple theories have been proposed to explain physicians, general emergency physicians, orthopedic surgeons, this injury, the current evidence supports a partial annular liga- and sports medicine specialists. ment tear or momentary distraction of the radiocapitellar joint that occurs in pronation, allowing the annular ligament to slip under the radial head, becoming entrapped in the joint space.5,15–18 Be- LEARNING OBJECTIVES cause the anterior portion of the radial head is narrower and forms After completion of this CME article, readers should be better a more acute angle when compared with the posterior or lateral as- able to: pects, dislocation is more common in pronation.5,16,17 By the age of 5 years, the annular ligament is much thicker and stronger, 1. Describe the historical and physical examination findings thereby reducing the likelihood that it will tear or be displaced.16 suggestive of radial head subluxation and elbow dislocation. The most common mechanism for the injury is an axial 2. Differentiate reduction techniques for radial head subluxation pulling force applied to a child's arm in extension with the forearm and elbow dislocation. pronated.5,6,17,19 The left arm is affected more commonly than the – 3. Explain the disposition and follow up recommendations for right.6 8,11,12,14,20 This may be owing to the larger number of patients after reduction of a radial head subluxation and right-handed than left-handed caregivers or increased muscle elbow dislocation. strength in the patient's dominant arm.

ediatric orthopedic injuries are a common presentation to History and Physical Examination P emergency departments. Among these injuries, radial head Classically, the caregiver will report that the child refused to subluxation and elbow dislocation are 2 important upper extremity move his or her arm after the caregiver pulled on the child's dislocations. It is essential for providers to understand the diagnos- arm.5,6,11 The most common reasons the child's arm is pulled tic strategies, reduction techniques, and postreduction management are to prevent the child from falling, picking the child up after a for these common conditions. Each injury is discussed sequentially fall, pulling the arm through a tight sleeve, or swinging the child in the following sections. by the arms.5,11,20 Interestingly, up to 25% of cases are associated with a fall or direct trauma to the elbow.9–11 Children typically en- dorse elbow pain but may experience referred pain to the wrist Assistant Professor and Director of Ultrasound (Gottlieb), Department of 5,6 Emergency Medicine, Rush University Medical Center, Chicago, IL; Assistant or shoulder. Professor (Suleiman), Department of Orthopedic Surgery, Rush University Med- The affected arm is held against the body with the elbow in ical Center, Chicago, IL. slight flexion and the forearm pronated. There is usually no swell- The authors, faculty, and staff in a position to control the content of this CME ing, deformity, or point tenderness of the elbow or distal humerus. activity and their spouses/life partners (if any) have disclosed that they have 16 no financial relationships with, or financial interest in, any commercial There may be slight tenderness to palpation of the radial head. organizations relevant to this educational activity. Pain is elicited with passive pronation and supination, although Reprints: Michael Gottlieb, MD, RDMS, Department of Emergency Medicine, flexion and extension are usually painless.16,21 However, patients Rush University Medical Center, 1750 West Harrison St, Suite 108 Kellogg, Chicago, IL 60612 (e‐mail: [email protected]). may still become upset with these movements owing to the asso- Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved. ciated anxiety. Although a classic history and examination support ISSN: 0749-5161 the diagnosis of radial head subluxation, the provider should

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FIGURE 1. Supination (left) followed by flexion (right) technique for forearm reduction. examine and palpate the entire arm and clavicle to avoid missing Although the child may be hesitant to move the arm, movement can an alternate or concomitant injury. be elicited by offering a toy or sticker and having the child reach with the affected arm. Postreduction radiographs are not indicated unless Imaging the child continues to not move the arm or there is concern for iatrogenic injury. Radial head subluxation is a clinical diagnosis, and radiographs are rarely necessary. However, radiographs should be obtained when there is an obvious effusion, ecchymosis, tenderness Complications to palpation, or a significant mechanism of injury. Radiographs Neurologic or vascular damage are exceedingly rare with this should also be considered if the child does not resume moving injury. The most common complication is a predisposition to re- the arm after the reduction. Radiographs often appear normal in ra- current radial head dislocations, with recurrence rates ranging dial head subluxations.5 However, studies have suggested that fail- from 23% to 39%.5–9 Risk of recurrence is more common in pa- ure of a line extending in the longitudinal direction from the radius tients who present under the age of 2 years.5,7–9 However, studies to bisect the capitellum (ie, radiocapitellar line) may suggest radial have not demonstrated a significant difference in recurrence rates head subluxation.22,23 Commonly, the forearm will undergo inci- based upon duration of follow up interval, sex, laterality, or family dental reduction while obtaining the radiographs.11,16 history of radial head subluxation.6,8 Although not commonly used, ultrasound may facilitate the diagnosis of this condition. A linear probe is used to evaluate Disposition the location of the radial head and surrounding structures. Findings Neither splinting nor orthopedic referral is required after a include a widened space between the radial head and capitellum, in- successful reduction. If reduction fails after both techniques, place creased joint space echogenicity, visualization of the supinator mus- the patient in a posterior long arm splint and have the patient fol- cle entering the joint space (ie, the “hook sign”), displacement of – low up with an orthopedic surgeon in 1 to 2 days. the annular ligament, and enlargement of the synovial fringe.24 29 It is also important to educate parents to avoid traction on the forearm and elbow to avoid recurrence of the subluxation. One Management case series even described successful reduction of recurrent sub- There are 2 primary techniques for reducing radial head subluxations by parents while receiving instructions over the phone luxations. Although both techniques were discovered in the same by a trained medical provider.40 year, supination-flexion has been the predominant technique em- Recurrent subluxations may benefit from immobilization phasized for over a century.21,30–32 However, more recent data after the reduction in a posterior long arm splint with the elbow have challenged this reduction strategy.9,20,33–39 Both techniques are described hereafter, as it is the authors' opinion that either technique should serve as a secondary reduction strategy if the first attempt is unsuccessful. The supination-flexion technique involves supinating the patient's affected forearm and flexing the arm at the elbow in one fluid motion (Fig. 1). The second approach, referred to as the hyperpronation technique, involves extending the arm at the elbow and fully pronating the arm (Fig. 2). A variant of this technique may be performed with the elbow flexed at 90 degrees. Gen- tle pressure on the radial head with the provider's thumb may also assist with the reduction using both techniques. Typically, a popping sensation will be felt or less often heard, when the radial head reduces. Presence of this finding is associated with a positive predictive value of 92% to 98% and a negative predictive value of 69% to 76%.6,7 When comparing the supination-flexion technique with the hyperpronation technique, studies have suggested that the latter technique is more effective and less painful.9,20,33–39 Typically, the child will begin using the arm within 10 minutes, although the delay may be longer in children under the age of 2 years.7 FIGURE 2. Hyperpronation technique for forearm reduction.

Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved. Pediatric Emergency Care • Volume 35, Number 4, April 2019 Management of Forearm and Elbow Dislocations maintained at 90 degrees and the forearm supinated. Open re- of the natural contour of the elbow.52 As with other injuries, the duction or repair of the annular ligament may be required but provider should examine and palpate the entire arm and clavicle is exceedingly rare.41 to avoid missing an alternate or concomitant injury.49 The provider should also evaluate the distal radioulnar joint and interosseous membrane for tenderness and instability to rule out an interosseous ELBOW DISLOCATIONS membrane disruption, which is a variant of the Essex-Lopresti injury.60 In addition, the provider should perform a thorough Background neurovascular assessment. Patients may have decreased pulses Elbow dislocations in the pediatric population are relatively acutely after the injury, but this is typically owing to swelling near or compression of the brachial artery and resolves after the reduc- uncommon injuries but require prompt management in the emer- 51,61 gency department when they occur. Traumatic elbow dislocations tion in most cases. If the pulse deficit does not resolve after the reduction, computed tomography or conventional angiography comprise approximately 3% of all elbow injuries in skeletally im- 61 mature patients.42 In the United States, the incidence of pediatric is recommended. elbow dislocations is 6.87 dislocations per 100,000 person-years among children between 10 and 19 years of age.43 These injuries Imaging occur most commonly in adolescents with a peak incidence be- When elbow dislocations do occur, pure dislocations without tween 13 and 14 years of age and have a 2:1 male-to-female evidence of fracture are rare.62 Therefore, radiographs must be care- – ratio.42 44 Although this injury is more commonly seen in older fully evaluated and scrutinized for an associated fracture or avulsion. children, it has been reported in children as young as 18 months.45 Medial epicondyle fractures are the most common presenting fracture associated with a pediatric elbow dislocation and can occur in up to Anatomy and Pathophysiology 50% of elbow dislocation cases.44,53,56,57,63–65 Knowledge of the static and dynamic stabilizers of the elbow Diagnostic imaging for elbow dislocations must include both 51 is important to help the medical care provider to understand the as- an anteroposterior and lateral radiograph of the elbow. If a me- sociated injuries and successful reduction maneuvers. The static dial epicondyle fracture is suspected, an additional oblique view constraints around the elbow are divided into osseous and ligamen- should be obtained to evaluate for an incarcerated fragment within 66,67 tous structures. The osseous structures create a bony hinge to stabi- the joint space. When examining postreduction radiographs, it lize the elbow with the coronoid and olecranon providing the is important to evaluate them for widening or irregularity of the majority of the osseous stability.46 With regard to the ligamentous joint, as this may suggest an entrapped osteochondral fragment 49,51,68 structures, the anterior band of the medial ulnar collateral ligament or an inadequate reduction. Computed tomography and is the most important structure and can lead to significant joint in- magnetic resonance imaging have minimal utility in the acute set- 49 stability if damaged.47 This ligament originates from the medial ting but may be valuable for operative planning in select cases. epicondyle and can result in an avulsion of the medial epicondyle in children with incomplete closure of the growth plate.48 The dy- Management namic stabilizers around the elbow are less important and play a After initial assessment of the neurovascular status and radio- much smaller role compared with the static stabilizers. graphic examination, the reduction should be performed urgently. Posterior elbow dislocations are the most common form of For both anterior and posterior elbow dislocations, it is imperative elbow dislocations, occurring 90% of the time, whereas anterior that adequate anesthesia or sedation is provided for the child to be dislocations are much less common, occurring in only 1% of 49–51 completely relaxed. This may be performed with systemic seda- dislocations. It is theorized that the mechanism for the injury tives and/or analgesics, a regional nerve block, or intra-articular is an initial valgus force leading to failure of the medial struc- injection of a local anesthetic.58,69–71 tures.52 Commonly, this will lead to a medial epicondyle avulsion 53 Before the reduction attempt, the forearm should be or fracture. Consequently, the ulna and radius displace laterally, hypersupinated.53 This allows the coronoid fragment to disengage leading to disengagement of the coronoid and the resultant dislo- 52,54 and the radial head to dislodge from their current position in cation. A shallow olecranon fossa with a prominent olecranon space.53 In addition to the osseous components, the biceps tendon tip has been suggested to predispose to these dislocations.55 Stud- ies have also demonstrated that the left elbow is dislocated more commonly than the right.44,50,56,57 This may be owing to weaker stabilizers of the nondominant arm or to a protective instinct to shield the dominant arm when an individual falls.49

History and Physical Examination Patients typically present with severe elbow pain and swelling after a fall or trauma to the elbow.51 The patient may also complain of paresthesias, most commonly in the ulnar distribution.51,58 Inju- ries often occur during a sporting activity or motor vehicle collision with one study suggesting that three quarters of all dislocations oc- curred while playing a sport.51 The most common mechanism is falling onto an outstretched arm.51 On initial presentation, the elbow will typically be extended with the arm abducted.51 Often, the medial aspect of the distal humerus will be palpable.59 The presence of skin dimpling and prominence of the distal humerus articular surface are highly suggestive of an elbow dislocation.53 In a posterolateral elbow dislocation, the olecranon will be posteriorly displaced leading to a loss FIGURE 3. Traction/countertraction technique for elbow reduction.

concomitant lateral collateral ligament injury).58 In this case, splint the elbow at 90 degrees with the forearm in pronation, as this position reduces the radial head and promotes healing of the lateral ligamentous complex.58 Anterior elbow dislocations are much less common and require a modification from the technique used for posterior dislocations. For anterior elbow dislocations, reduction is achieved by flexing the elbow and applying a downward force on the proximal forearm, rather than the distal humerus.80 Once postreduction radiographs have assessed the quality of reduction, the elbow should be immobilized in slight extension rather than flexion (as in posterior dislocations) to reduce the likelihood of repeat dislocation.81,82

Complications Pediatric elbow dislocations must be thoroughly evaluated for neurovascular compromise and associated injuries in the shoulder, forearm, wrist, and hand. Associated neurologic or vascular injuries to the upper extremity occur in approximately 10% FIGURE 4. Interlocking fingers technique for elbow reduction. to 15% of cases.83 Neurologic injuries most commonly affect

57 the ulnar nerve, although median nerve injury may also oc- will also relax, thereby facilitating the reduction. There are several cur.56,57,61,65,84,62 Vascular injuries are rare, occurring in only potential reduction techniques from this position. The most com- 3% of reported cases, and the majority of injuries involve the bra- mon technique is traction-countertraction. With this approach, lon- chial artery.56,84 Although avulsion of the medial epicondyle is the gitudinal traction is applied on the forearm with countertraction most common fracture, concomitant radial head and neck frac- applied to the distal humerus (Fig. 3). The countertraction may be 49,85 72 tures can occur in 5% to 10% of cases. When the radial head, applied by either another provider or a folded bedsheet. The pro- coronoid process, and medial collateral ligament are fractured, vider may also apply direct pressure on the olecranon process to fa- this is often referred to as the “terrible triad” of the elbow owing “ ” cilitate the reduction attempt. The provider will often feel a clunk to frequent problems with instability, stiffness, and degenerative as the reduction occurs. The presence of this finding is a favorable 58,86 49 changes. In rare cases, compartment syndrome has been reported sign of joint stability. owing to the edema and associated hematoma.58,61 Therefore, it is An alternate, single provider technique for reduction was 73 important to be vigilant for signs of early compartment syndrome. first described by Hankin in 1984. This technique involves the Loss of motion will occur in most patients who sustain an el- use of the provider's forearm as a fulcrum to assist the reduction bow dislocation; however, patients typically lose no more than 10 in a slow and controlled manner (Fig. 4).72,73 This approach be- 53,87 72,73 degrees of extension. Late complications can include recur- gins by gently supinating the patient's affected arm. Then, rent dislocations, stiffness, and radioulnar synostosis.53 It is im- the provider interlocks his or her fingers with the patient's fingers portant to be aware that neurovascular injuries have been in a clasping grip and places the provider's elbow against the distal 49,73,88 72,73 identified as a result of the reduction attempt. Therefore, portion of the patient's biceps muscle. Providers may grip the it remains essential that a prompt neurologic and vascular exami- patient's wrist instead of fingers if the patient has a longer forearm nation is performed after the reduction attempt.73,88,89 length. The provider then slowly draws the patient's elbow into flexion, using the provider's elbow as a fulcrum at the elbow joint. Disposition The provider can also add medial or lateral pressure with the alter- After a successful reduction with a simple dislocation, im- nate hand for lateral or medial dislocations, respectively. Skelley 87 and Chamberlain72 compared this technique with the traction- mobilization with close orthopedic follow-up is appropriate. Splints are typically removed within 2 weeks, as prolonged immo- countertraction technique among a sample of 16 patients and found 51,89–91 that the single provider technique was able to reduce 2 elbows that bilization is associated with worse outcomes. Operative repair of uncomplicated reductions is rarely required, occurring in were unsuccessful with the traction-countertraction maneuver. No 89,92,93 complications were identified with either reduction technique.72 only 1% to 2% of cases. Complex dislocations with an A third approach involves a modification of the Stimson associated fracture, elbows that are unable to be reduced after technique used for hip and shoulder dislocations.74–77 This ap- several attempts, or elbows that do not stay reduced warrant or- proach involves placing the patient supine on the bed with the up- thopedic surgery consultation to evaluate for possible acute per arm abducted and the forearm located over the side of the bed. surgical intervention. The provider uses a slow downward force along the long axis of the forearm, while manipulating the olecranon process with the alternate hand to achieve reduction.74–76 Although well supported CONCLUSIONS in the adult literature, this technique can be challenging in chil- Pediatric orthopedic injuries are a common presentation that dren, as they may not tolerate lying in this position for an extended require urgent evaluation and management. This article discussed time. In addition, if procedural sedation is required, this position 2 important upper extremity injuries, radial head subluxation and may limit the ability to monitor the patient's airway and breathing. elbow dislocation, with a focus on diagnostic strategies, reduction Several studies have recommended against initial hyperex- techniques, and postreduction management. tension of the elbow owing to risk of entrapment of the median nerve.57,78,79 Once reduction is achieved, the elbow should be immobilized in 90 degrees of flexion with the forearm in neutral REFERENCES 57,52 position using a posterior long-arm splint. Occasionally, the 1. Schutzman SA, Teach S. Upper-extremity impairment in young children. elbow will not maintain the reduction (typically owing to a Ann Emerg Med. 1995;26:474–479.

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