Radial head subluxation (RHS) OR PULLED ELBOW is a common disorder in children. Although it is not accompanied by any important short- or long-term sequel, it could make the parents worried about. Objective or purpose: The purpose of this study was to determine the possible effective factors that may influence time to use the affected limb. Methods: This cross-sectional study was conducted prospectively during the years 2014 to 2016. All children under the age of 6 years who visited the emergency department (ED) and were diagnosed as having RHS were eligible. The patients’ baseline information was recorded. After the reduction, the time until the affected arm use returned was recorded. The possible relationship between the baseline data and time to re-use the affected limb was assessed. 

Results

During the study period, 112 children with a mean age of 30.18 ± 18.18 months were evaluated (53% male). Among the children who visited the ED during the first 4 hours and thereafter, 84% and 60%, respectively, re-used their limb in less than 10 minutes after reduction (p = 0.004). Also, 55% of children less than or equal to 24 months and 89% over the age of 24 months re-used the arm in 10 minutes (p < 0.001). The success rate of the first reduction maneuver was significantly lower in children with a recurrent dislocation (p = 0.001).

Conclusion

It is likely that age less than or equal to 24 months and ED visit after 4 hours of the event lead to a longer duration for re-using the affected arm following reduction.

Radial head subluxation (RHS), also called "pulled elbow" or "nursemaid's elbow," is a common disorder in children [1-4]. Although it is not accompanied by any important short- or long-term sequel, it could make the parents worried about. Although most of the cases are seen in those under the age of 7 years, PULLED ELBOW  has been reported in children younger than six months of age or even until the age of 18 years [5, 6]. RHS is a frequent elbow injury in young children, affecting approximately 20,000 children per year in the United States [7,8]. Since there are cases of spontaneous reduction, it is difficult to determine its actual occurrence rate. This injury usually occurs in the left hand and is more common in girls [9,10]. The most common mechanism is the pulling of the arm while the child's elbow is completely open and the forearm is rotated inwards. This mechanism usually occurs when the child is wounded by parents or other caregivers. The mechanisms of RHS such as swinging the child by the arms, lifting the child, or wrestling may more often involve male aregivers while RHS caused by pulling away, tripping, or getting dressed appears to be associated more with female caregivers [7, 11, 12]. 

As a result, a portion of the annular ligament over the radial head slips into the radiohumeral joint space, where it becomes locked in. Sometimes this lag is torn and falls between the head of the radius and the capitellum [1, 3]. The child cries and does not use the affected arm and resists any attempts to move passively. The child holds the arm close to the body with his/her elbow in extension and the forearm pronated [10]. The diagnosis of RHS can be made when the characteristic history, physical examination findings, and the position of the arm are present in a child [1, 2, 4]. There is no focal bony tenderness, bruising, deformity, or swelling. RHS is a clinical diagnosis, and radiologic investigation is usually not needed unless the history of injury is not clear, or attempts to reduce failed, or there is suspicion of child abuse, and if there is spontaneous improvement within 30 minutes. In such cases, radiographs are obtained to rule out a possible fracture [13, 14]. Most children are able to use the affected arm, early after reduction, but some are associated with delays in the use of the affected arm leading to repeated attempts at reduction. The purpose of this study was to determine the possible effective factors that may influence the time to use of the affected limb. 

A cross-sectional study was conducted prospectively during the years 2014 to 2016. It was performed at the emergency department (ED).  Study population All children under the age of 6 years who visited the ED and were diagnosed as having an RHS were eligible. In the absence of specific diagnostic features, the diagnosis was performed on the basis of a characteristic history and physical examination, but the diagnosis was confirmed based on the child using the affected arm after the reduction. Children with deformity, swelling, edema, and ecchymosis in the elbow area as well as children with multiple traumas and patients diagnosed with any other injury during the study were excluded. Reduction method Different methods are used for reduction. One of the treatments is the supination/flexion method. The examiner supinates the forearm and flexes the elbow by applying pressure on the radial head by the opposite hand. The other method is the hyperpronation method wherein the examiner hyperpronates the forearm and applies pressure with the other hand on the radial head. A click may be felt by the finger over the radial head, or a pop may be heard by the examiner when the displacement is reduced [15, 16]. 

Data gathering The patients’ baseline information including age and sex, chief complaint, mechanism of injury, time of injury, side of injuries, previous history of trauma, and the number of similar injuries were recorded. After the reduction, the reduction method, the presence or absence of a heard click, the number of reduction attempts, and the time until the affected arm use returned were recorded in a pre-prepared checklist. Patients were visited by emergency medicine residents and were treated by the hyperpronation method. If the child did not use his/her arm within 15 minutes after the maneuver, the reduction was re-suspended by the emergency medicine specialist using the same reduction method, and if he/she did not use the arm after 15 minutes, another method was used to reduce it. When the affected arm use returned, it was considered as a successful reduction. Three failed maneuvers were considered as a treatment failure. If the child did not use the arm after trying the maneuver two times or after 30 minutes, a radiograph was requested. Statistical analysis The statistical analyses were performed using SPSS-20 software. The data were analyzed using Chi-square and Kruskal–Wallis tests. 

 During the study period, 112 children were brought to the ED by their parents due to elbow pain and lack of use of the upper limbs. The mean age of the children was 30.18 ± 18.18 (range from 7 to 71) months, and the age of a majority of them (65%) ranged from 21 to 46 months. The baseline characteristics of the studied patients are reported in table 1. Of these children, 59 were boys (53%), and 53 were girls (47%), indicating a higher incidence in boys. In 67 children (60%), the left hand was involved. Ten children had swelling, ecchymosis, and edema of the elbow and were excluded from the study. The other children were treated based on the diagnosis of RHS, history and mechanism of injury, and physical examination findings. Sixteen patients with a previous history of RHS  (18.8%) were referred for recurrent dislocation, and 76% of them experienced a dislocation in the same limb. Although the most prevalent mechanism identified was pulling of the forearm (51.0%), there were some other causes such as direct trauma or fall. After reduction, 56% of the children used the affected arm immediately or within 5 minutes. According to the results, among the children who visited during the first 4 hours, 84% used their limb within 10 minutes after reduction and 16

In the current study, the age of the child and the time period from the event to visiting the ED corresponded to a longer duration for re-using the affected arm following reduction. A majority of the children’s age was in the range of 21-46 months, which is similar to that reported by other studies (1, 3, 4). The minimum age was 7 months, and no child under 6 months of age was seen. RHS was more common in boys (53%), which is different from the results of most of the prior studies conducted in other countries but similar to another study carried out in ITALY (9, 17, 18). According to the earlier studies, the left hand was most commonly affected, whose possible cause is the dominant right-handed parenthood, in which case the child's left hand is usually held. Similar to other studies, the most common mechanism for dislocation was pulling the arm (1, 3). Recurrent dislocation was seen in about 19% of the cases. The chance of recurrent RHS in various studies has been reported to be from less than 5% to about 30%-39% (1, 10). 

There is a controversy about the time of re-using the affected arm after the reduction and is reported to be from 30 minutes to later (10, 19). According to a study, 56% of the children were able to use the affected arm immediately and within 5 minutes of reduction, and this number was 74

The baseline characteristics were chosen based on expert opinion. A better search would be more valuable for being considered in the checklist of the study. The performed statistical analysis is not conclusive and just report the possibility of the influence of some factors on time to re-use the affected limb. We strongly suggest other investigators to prepare a comprehensive checklist or use data-registry if available. 

In the current study, age less than or equal to 24 months and visiting ED after 4 hours of the event lead to a longer duration for re-using the affected arm following reduction.