Reconsidering the "Classic" Clinical History Associated with Subluxations of the Radial Head

Abstract

Introduction: The national burden of radial head subluxations in the United States (U.S.) population is poorly defined, and non-classical injury mechanisms have been increasingly reported in recent years. The purpose of this study is to report historical national estimates and demographic characteristics of patients presenting to U.S. emergency departments (ED) with subluxations of the radial head.

Methods: This cross-sectional, retrospective study analyzes the National Electronic Injury Surveillance System (NEISS) database (2001-2017) to identify patients ≤ 7 years of age presenting to U.S. EDs with subluxations of the radial head.

Results: Linear regression (R2 = 0.65; P < 0.01) demonstrated that the annual number of patients presenting to U.S. EDs with subluxations of the radial head increased significantly (P < 0.001) between 2001 (N=13,247; confidence interval [CI], 9,492-17,001) and 2010 (N=21,723; CI, 18,762-24,685), but did not change significantly between 2010 and 2017 (R2 < 0.01; P = 0.85). It also demonstrated that 51.0% (CI, 45.3%-56.6%) of injuries were either self-induced or spontaneous, whereas 36.8% (CI, 31.6%-42.0%) and 9.4% (CI, 8.0%-10.7%) were associated with parents/guardians or siblings, respectively. The majority of injuries occurred in patients who were the age of one (33.5%; CI, 32.1%-35.0%) and two (35.1%; CI, 33.7%-36.6%); females (57.8%; CI, 56.8%-58.9%) were more commonly injured than males.

Conclusion: Although the national burden of radial head subluxations may be less than previously reported, it still results in over 20,000 ED visits annually in the U.S. Given that over half of such injuries are actually self-induced or spontaneous, caretakers should be taught to recognize the clinical presentation of radial head subluxation, since the classically described history of a patient being lifted or pulled by the arm may simply have never occurred.

Figure 1

Weighted national estimates of pediatric patients presenting to U.S. emergency departments (EDs) with subluxations of the radial head, 2001–2017. CI; confidence interval. This figure overlays two linear regression models for the annual national estimate of radial head subluxations presenting to U.S. EDs between 2001 and 2017. The first linear regression model (blue, dotted line) uses annual national estimates (blue, filled diamonds) from 2001 to 2010 as inputs. The second linear regression model (orange, dotted line) uses annual national estimates (orange cross marks) from 2010 to 2017 as inputs. Results from the linear regression models are shown in the text boxes directly above each model.

Figure 2

Ages of pediatric patients presenting to U.S. emergency departments with subluxations of the radial head, 2001–2017. *The estimate is considered to be potentially unstable due to the number of unweighted cases from the sample frame totaling <20, the weighted national estimate totaling <1200, or coefficient of variation >33%. Therefore, no standard errors or confidence intervals are provided; the unstable percentage estimate is provided for reference purposes only. Variable results with sample frame totals <20 cases or percentages <0.1% were omitted from this table, resulting in percentage totals not necessarily summing to 100%. ^‡Age groupings are based on “Age stages defined according to the Eunice Kennedy Shriver National Institute of Child Health and Human Development pediatric terminology” defined by Williams et al. (2012) in paper entitled, “Standard 6: age groups for pediatric trials.”