Summary

An updated report on the epidemiological trends of sports-related SC dislocations that present to Emergency Departments across the United States.

Abstract

Background

The sternoclavicular (SC) joint is a stable diarthrodial saddle that rarely dislocates, with literature dating back to 1958 indicating that these injuries represent less than 3% of joint dislocations involving the shoulder. The rarity of SC dislocations generates little consensus on current injury epidemiology.

Purpose

The purpose of this study is to evaluate epidemiological trends of sports-related SC dislocations that present to Emergency Departments (EDs) across the United States.

Methods

Data were obtained from the National Electronic Injury Surveillance System (NEISS) database using a query for “upper trunk” and “shoulder” dislocations between 2001-2020, although secondary injuries were only coded beginning in 2019. All narrative summaries were reviewed. Data on incidence, patient demographics including age and sex, mechanisms of injury, dislocation types, incident locales, and patient dispositions were collected and analyzed. Weighted population statistics were calculated based on census data with incidence rates per 1,000,000 persons at risk and corresponding 95% confidence intervals (CIs). Mid-p two-sided p-values were calculated for all incidence rate ratios and Poisson approximations to construct incidence rate CIs. Chi-squared tests were used to compare dislocation rates in comparable patient cohorts.

Results

An estimated 1,622 SC dislocations occurred nationwide from 2001-2020 with an incidence of 0.262 dislocations per 1,000,000 people (CI=0.250-0.275), comprising 0.1% of all shoulder and upper trunk dislocations. The cumulative incidence was 0.262 dislocations per 1,000,000 people (CI=0.250–0.275) over the study period. Most patients were male (91%, n=1480) and aged 5-17 (61%, n=982). The incidence of sports-related dislocations in male patients was over ten times higher than the corresponding incidence in female patients (0.471 per 1,000,000 people, CI=0.447–0.496; 0.046 dislocations per 1,000,000 people, CI=0.039–0.055, odds ratio [OR]=10.1, CI=8.49–12.1).

Football, wrestling, and biking were the most frequently implicated sports (49%, n=795; 9%, n=151; 8%, n =121, respectively), with contact sports responsible for 59% of athletic injuries (n=961). Anterior versus posterior dislocations were not often documented, but all recorded posterior dislocations occurred in males ages 15 – 17 with half of posterior dislocations sustained during football. The greatest proportion of SC dislocations occurred at places of recreation or sport (57%; n=917) followed by homes (14%; n=235) and schools (5%, n=82).

Ultimately, 82% of patients were discharged from the ED (n=1337), 12% were admitted (n=194), and 6% were transferred (n=90). All recorded posterior dislocations were admitted or transferred from the ED.

Conclusion

SC dislocations comprise approximately 0.1% percent of all shoulder and upper trunk dislocations. Establishing contact sports as a common source of injury further offers value in raising clinical suspicion to secure the correct diagnosis early on in injury timeline. Most patients are discharged directly from the ED; however, a substantial number are hospitalized. Patients whose injuries were sustained from contact sports were also more likely to be admitted or transferred, suggesting these injuries may be more severe than those from other athletic activities. Understanding the epidemiology and mechanism-related trends of acute SC dislocations is important given the potential severity of these injuries, concentration in a specific population, and uncertainty linked to rare presentation.