Epidemiology of Shoulder Dislocation Treated at Emergency Departments in the United States Between 1997 and 2021.

BACKGROUND: The exact incidence of shoulder dislocation in the general population of the United States (US) has yet to be well studied.

PURPOSE: To establish the current incidence and patterns of shoulder dislocations in the US, especially regarding sports-related activity.

STUDY DESIGN: Descriptive epidemiology study.

METHODS: This was a retrospective analysis of shoulder dislocations encountered in emergency departments in the US between 1997 and 2021 as recorded in the National Electronic Injury Surveillance System (NEISS). Data were further analyzed according to patient age, sex, and sports participation. Information from the United States Census Bureau was used to determine the overall incidence of dislocations.

RESULTS: A total of 46,855 shoulder dislocations were identified in the NEISS database, representing a national estimate of 1,915,975 dislocations (mean 25.2 per 100,000 person-years). The mean patient age was 35.3 years. More than half of the dislocations (52.5%) were sports-related, and basketball (16.4%), American football (15.6%), and cycling (9%) were the sports most commonly associated with dislocation. Most dislocations (72.1%) occurred in men. This disparity by sex was more significant for sports-related dislocations (86.1% in men) than nonsports-related dislocations (56.7% in men; P < .001). With sports-related dislocations, people <21 years experienced a significantly higher proportion versus those >39 years (44.6% vs 14.9%; P < .001), while the opposite distribution was seen with nonsports-related dislocations (<21 years: 12% vs >39 years: 51.7%; P < .001). Women outnumbered men with shoulder dislocation among people >61 years.

CONCLUSION: Sports-related shoulder dislocations were more common among younger and male individuals than older and female individuals. Contact sports such as basketball and American football were associated with more shoulder dislocations compared with noncontact sports.