Abstract
Radial head subluxation (RHS) is the most common upper extremity injury in children. Supination–flexion (SF) and hyperpronation (HP) are two methods for reducing this subluxation. This study purposed to compare the success rates of two methods of reduction and also to determine which technique would be less painful. In total, 154 patients with RHS were enrolled in this study and randomized into two groups. Patients were to undergo reduction by one of the two methods; if the primary attempt was unsuccessful, a second attempt was performed using the alternate technique. In the case of failure of the second attempt, the first reduction technique was repeated. The success rates and pain levels before and after successful reduction were recorded. On the first attempt, 72 of 77 patients who underwent HP had a successful reduction. Four patients in the HP group had a successful reduction on the second attempt. In the SF group, 76 of 77 patients had a successful reduction on the first attempt. The success rate on first attempts was higher in the SF group than in the HP group ( p = 0.043). Pain levels before and after reduction were not statistically different between the groups ( p > 0.05). The SF technique had a higher success rate at first attempt to reduce RHS, but pain levels were similar in both methods.
Keywords: radial head subluxation, supination–flexion, hyperpronation, emergency medicine
Introduction
Radial head subluxation (RHS), also called “pulled elbow,” “nursemaid's elbow,” or “temper tantrum elbow,” 1 is the most common upper extremity injury in children. 2 It refers to the subluxation of the radial head from the annular ligament and usually occurs with axial traction to the forearm while the child's arm is in extension and the forearm is in pronation. 3 RHS is more common in children between 1 and 4 years of age, and it is more predominant in girls and in the left arm. 4 The most common mechanism of this injury is a pull injury to the arm, that is, it occurs when a child is falling and the individual holding the hand does not let go. 5 This sudden longitudinal traction results in subluxation of the head of the radius. 6
RHS is diagnosed based on patient's history and physical examination. 4 In such cases, the child experiences a sharp pain and refuses to use the arm. 7 Passive movements are met with resistance by the child, and on examination, the absence of severe tenderness, deformity, or edema is noted. 8
Supination–flexion (SF) and hyperpronation (HP) are two methods for reducing RHS. The SF technique involves supination at the wrist followed by flexion at the elbow, whereas the HP technique involves pronation of the wrist. 9 After reduction, the child regains function of the arm. 1 In such case, the elbow is in extension and the forearm is in pronation, and attempts to put the forearm in supination position cause pain. 3
Multiple studies compared HP with SF in reducing RHS. 5 Although many studies used HP method on RHS reduction, several articles reported that the SF method is effective as well. 10 The current study aimed to compare these two reduction techniques in patients who presented to the emergency department (ED) with RHS. The objective of our study was to determine which method has the higher success rate and is less painful.
Methods
This study was conducted in accordance with the Consolidated Standards of Reporting Trials (CONSORT). 11
Trial Design
This clinical, prospective, randomized, controlled study examined children with symptoms compatible with RHS who presented to the ED of Ahvaz Imam Khomeini Hospital between February 2018 and August 2019. Diagnosis was made based on clinical signs, physical examination, and radiography if required.
This study was approved by ethics committee and registered with http://www.irct.ir/ . Written informed consent was obtained from a parent or guardian for all participants included in the study.
Participants
A history was taken and a physical examination was performed for each patient complaining of an upper extremity injury before enrollment. Children were eligible to participate in the study if they were younger than 6 years and had a suggestive clinical presentation of RHS. Patients were excluded if they were older than 6 years or had marked deformity, local swelling, ecchymosis, or point tenderness, or if they had a fracture in the same extremity. If they had typical history for RHS, no radiographs were taken.
Interventions
The SF method is complete flexion of the elbow with supination of the forearm, and the HP method is the HP of the elbow with no any flexion or extension.
Children underwent reduction by one of the two methods based on the random allocation and were re-examined 5 minutes after the reduction attempt. If the patient started to use the arm, the reduction was accepted as successful. If the primary attempt was unsuccessful, a second attempt was made using the alternate technique. After failure of the second attempt, the first reduction technique was repeated. If the third reduction attempt was unsuccessful, an orthopaedic consultation was requested.
Outcomes
Before the first attempt and 5 minutes after a successful reduction, pain levels were recorded based on the face, legs, activity, cry, consolability (FLACC) scale. In this system, the patients' facial expressions, leg movements, activity, the extent to which they are crying, and the extent to which they can be consoled are recorded. Then, they are scored within the range of 0 to 10 ( Table 1 ). 12
Table 1. FLACC scale system.
| 0 | 1 | 2 | |
|---|---|---|---|
| Face | No particular expression or smile | Occasional grimace or frown, withdrawn, uninterested | Frequent to constant quivering chin, clenched jaw |
| Legs | Normal position or relaxed | Uneasy, restless, tense | Kicking or legs were drawn up |
| Activity | Lying quietly, normal position moves easily | Squirming, shifting, back and forth, tense | Arched, rigid, or jerking |
| Cry | No cry (awake or asleep) | Moans or whimpers; occasional complaint | Crying steadily, screams or sobs, frequent complaints |
| Consolability | Content, relaxed | Reassured by occasional touching, hugging, or being talked to; distractible | Difficult to console or comfort |
Abbreviation: FLACC, face, legs, activity, cry, consolability.
Sample Size
Statistical power calculations refer to pretrial calculations aimed at determining the minimum sample size required for this clinical study based on a previous study. 13 The sample size was determined by the calculation of “Cohen's d ,” and the minimum size for each group was estimated to be of 70 patients.
Randomization
Patients who met the study criteria were randomly assigned into two groups to begin the protocol with either the HP technique or the SF technique assigned by a computer-generated blocked randomization list.
Blinding
All evaluations and reductions were performed by one of the medical interns from a team of emergency medicine and orthopaedics specialists who was blinded to the situation of this study and had completed a dedicated training course in RHS reduction.
Statistical Methods
Age and pain levels were analyzed using t -test. Reduction success rates were analyzed using the chi-square test. Analyses were performed with the SPSS 22 package program. A p -value of < 0.05 was considered statistically significant.
Results
Of the 154 patients enrolled in this study, 63 were boys and 91 were girls ( Fig. 1 ). Girls comprised 62.3% of the HP group and 55.8% of the SF group. There was no statistical difference between the two groups in the distribution of gender ( p = 0.413). The mean age in the SF group was 29.05 ± 11.75 months and in the HP group was 28.53 ± 12.22 months. The groups were similar in terms of demographic data. In the HP group, 37.7% and in the SF group, 44.2% of patients had subluxation in their right elbow. In both groups, the most frequent cause of RHS was traction by another person (71.4% in the HP group and 63.6% in the SF group). The injuries of 31 and 24.7% of patients in the HP and SF groups, respectively, resulted from a fall. A history of trauma to the limb was seen in 5.2 and 3.9% of patients in the HP and SF groups, respectively. The mechanism of subluxation was unclear in eight patients in the HP group and six patients in the SF group. There was no statistical difference between the two groups ( p = 0.312) ( Table 2 ).
Fig. 1.
Flowchart of patients.
Table 2. Baseline characteristic of patients.
| Variables | Supination–flexion ( n = 77) | Hyperpronation ( n = 77) | p -Value | |
|---|---|---|---|---|
| Age, mo (mean ± SD) | 29.05 ± 11.75 | 28.53 ± 12.22 | 0.788 | |
| Gender, girl, N (%) | 48 (55.8) | 43 (55.8) | 0.413 | |
| Anatomic site of subluxation, N (%) | Right | 34 (44.2) | 29 (37.7) | 0.4 |
| Left | 43 (55.8) | 48 (62.3) | ||
| Mechanism of RHS | Traction | 49 (63.6) | 55 (71.4) | 0.312 |
| Falling | 19 (24.7) | 10 (31) | ||
| Trauma | 3 (3.9) | 4 (5.2) | ||
| Unclear | 6 (7.8) | 8 (10.4) | ||
| Previous subluxation | Had no previous history | 43 (55.8) | 48 (62.3) | 0.692 |
| 1 | 16 (20.8) | 11 (14.3) | ||
| 2 | 6 (7.8) | 9 (11.7) | ||
| 3 | 4 (5.2) | 3 (3.9) | ||
| More than 3 times | 8 (10.4) | 6 (7.8) | ||
Abbreviations: RHS, radial head subluxation; SD, standard deviation.
Table 2 shows the history of previous RHS in each group. In the HP and SF groups, 62.3 and 55.8% of patients, respectively, had no prior history of subluxation. There was no significant difference between the two groups ( p = 0.692).
With the HP method, 72 (93.5%) patients had a successful reduction on the first attempt, and 4 (6.5%) patients had a successful reduction on the second attempt. In the SF group, 76 (98.7%) patients had a successful reduction on the first attempt. The success rate on first attempts was higher in the SF group than in the HP group ( p = 0.043) ( Table 3 ). One patient in each group had a failed reduction on the third attempt, and an orthopaedic consultation was requested ( Table 3 ).
Table 3. Attempted reduction techniques and success rates.
| Variables | Supination–flexion ( n = 77) | Hyperpronation ( n = 77) | p -Value a | |
|---|---|---|---|---|
| Successful reduction, N (%) | First attempt | 76 (98.7) | 72 (93.5) | 0.043 |
| Second attempt | 0 | 4 (5.2) | ||
| Failed reduction | 1 (1.3) | 1 (1.3) | ||
| Orthopaedic consultation, N (%) | Yes | 1 (1.3) | 1 (1.3) | 0.99 |
| No | 76 (98.7) | 76 (98.7) | ||
| Pain score (mean ± SD) | Before reduction | 4.3 ± 3.13 | 4.53 ± 3.2 | 0.692 |
| After reduction | 0.67 ± 1.78 | 0.83 ± 1.66 | ||
Abbreviation: SD, standard deviation.
p < 0.05.
Note: A p -value of < 0.05 was considered statistically significant.
Pain levels before and after reduction were not statistically different between the two groups ( p > 0.05). Both HP and SF methods reduced the pain level after reduction ( p < 0.001) ( Table 3 ) ( Fig. 2 ).
Fig. 2.
Pain level comparison both group before and after reduction.
Discussion
The distal junction of the annular ligament, which covers the radial head, is weaker in children compared with adults. 4 It is thought that the main cause of dislocation is the radial head slipping beneath the annular ligament. 14 The SF technique is the most common method used for the reduction. However, when this method fails, HP may be an effective crossover technique. 9 Most prior studies showed that the HP technique is more effective than the SF technique; however, results of the current study suggest that the two techniques have similar success rates at first attempts for reducing RHS, with the SF technique being slightly effective.
Many studies compared the success rate of first reduction attempts and pain levels between HP and SF techniques. 15 Some studies have concluded that HP is more successful.
In a study of 88 patients with RHS, Guzel et al reported that 92% of patients in the HP group and 78% of patients in the SF group had successful reductions on first attempts ( p = 0.04). Based on the FLACC scale and Wong–Baker faces pain rating scale, no significant difference in pain levels before and after reduction was found between the two groups ( p = 0.462). 16 In another study, Ulici et al showed that HP was more successful than SF on the first attempt (85 vs. 53%), with no significant difference in pain levels before and after reduction. 13 García-Mata et al and few other researchers also reported that HP was more successful than SF on the first attempt. 6 7 17
However, a recent literature review showed that the evidence for the pronation technique being more successful than the supination technique for reducing RHS was of low quality. 10
Bek et al reported that among 66 children with RHS, reduction was achieved on the first attempt in 94% of patients in the HP group and in 69% of patients in the SF group ( p = 0.007). 3 Macias et al reported that in 85 patients presenting with RHS, 95% of patients in the HP group and 77% of patients in the SF group had successful reductions on first attempts ( p = 0.014). 9 In a study by McDonald et al, no significant difference was found in the success rate on first attempts between the two groups ( p = 0.186). 8
Similar to previous studies, the current study found the rate of RHS to be higher in girls and in the left arm. 5 6 7 The most common mechanism of this subluxation in both groups was traction.
In their meta-analysis, Bexkens et al showed that the HP technique was more effective than the SF one (risk ratio, 0.34; 95% confidence interval, 0.23–0.49; I 2 , 35%) and HP seemed to be less painful compared with SF. 5 However, the current study showed that the rate of successful first attempts was higher in the SF group than in the HP group ( p = 0.043); pain levels before and after reduction were not statistically different between the two groups ( p > 0.05).
Conclusion
The current study showed that the SF technique has a higher rate of successful first attempts for the reduction of RHS, but pain levels are similar in both methods. SF may be a convenient option for the reduction of RHS.
Funding Statement
Funding This study was funded by Samaneh Porozan: Ahvaz Jundishapur University of Medical Sciences, under Grant GP96028.
Footnotes
Conflict of Interest None declared.
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