Global variations in treatment and outcomes reported for anterior shoulder instability: a systematic review of the literature

BACKGROUND: Anterior shoulder instability is a common problem around the world, with a high risk for recurrence following the index dislocation. Surgical stabilization is commonly indicated for persistent instability, particularly in patients at high risk for recurrence, to minimize the risk of further labral injury and glenoid bone loss. However, there is little known about global geographic differences in the surgical management of anterior shoulder instability. As such, the purpose of this study was to evaluate and systematically review regional differences in the surgical treatment of anterior shoulder instability, particularly the indications for and outcomes from bony stabilization procedures compared to soft tissue procedures. METHODS: A systematic review, in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, was performed. Inclusion criteria consisted of level I and II evidence studies evaluating indications, techniques, and outcomes following operative management of anterior shoulder instability published from January 2000 to September 2021. Studies meeting inclusion criteria were grouped into four global regions (Asia, Europe, North America, South America) based on primary study location. Patient demographics, procedural details, patient reported outcomes, and complications (recurrence and reoperation rates) were compared between regions. RESULTS: Sixty (n = 60) studies (5480 patients) were identified. Eighty-six percent of all patients were male, with a mean age of 26.7 years. There was no difference in mean patient age, though patients undergoing bony stabilization procedures were older than those undergoing soft-tissue stabilization procedures (P = .0002) in all regions. The proportion of bony versus soft-tissue procedure groups did not differ significantly among regions. The indications for bony stabilization procedures varied significantly. Mean final follow-up was 3.5 years. Recurrent instability was 5.0% and did not vary across regions. However, recurrent instability occurred more frequently following soft-tissue compared to bony stabilization procedures (P = .017). South American studies utilized fewer anchors during soft tissue stabilization (P < .0001) and reported a higher reoperation rate compared to other regions (P = .009). CONCLUSION: There is global variation in the reporting of outcomes following surgery for anterior shoulder instability. The proportion of bony and soft-tissue procedures is similar, irrespective of geographic region. Recurrent instability does not vary by region but occurs more frequently following soft-tissue compared to bony stabilization procedures. There are a number of potential medical and nonmedical factors that may affect global variation in the surgical treatment of anterior shoulder instability.