Andrew Kuhn - Department of Orthopaedic Surgery, Washington University in St. Louis, MO, USA
Emma Landes - Washington University School of Medicine, St. Louis, MO, USA
Justin Yu - Washington University School of Medicine, St. Louis, MO, USA
Paul Inclan - Department of Orthopaedic Surgery, Washington University in St. Louis, MO, USA
J. Hill - Department of Orthopaedic Surgery, Washington University in St. Louis, MO, USA
Alexander Aleem - Department of Orthopaedic Surgery, Washington University in St. Louis, MO, USA

Objectives: To compile the existing literature on bilateral anterior shoulder dislocation (BASD) and analyze patient demographics, mechanisms of injury, injury characteristics, management, and outcome .Methods: This systematic review was conducted in accordance with Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) guidelines. Online databases, including Ovid Medline ۱۹۴۶-, Embase.com ۱۹۴۷-, Scopus ۱۹۶۰-, Cochrane Central, and Clinicaltrials.gov were systematically queried. Studies eligible for inclusion were case reports or case-series, documenting BASD. Two reviewers independently screened and applied a set of a priori exclusion criteria to each returned study. Data were extracted, compiled, and synthesized from each reported case of BASD. Contingency tables/Chi-Square Analyses, T-tests, and univariate regression analyses were conducted to assess relationships between different variables.Results: Eighty-one studies (۸۷ cases of BASD) were included. Patients were ۴۱.۱ (SD± ۱۹.۵) years old and most were male (n=۶۳; ۷۲.۴%). Around a quarter of patients (۲۸.۷%) had a history of epilepsy/seizures or were being worked-up for such. Younger males were more likely to have BASD due to a seizure or electrocution (P<۰.۰۵). Close to a third of cases (n=۲۷; ۳۱.۰%) were delayed in presentation. Those sustaining seizures or electrocutions were more likely to be delayed in presentation (P=۰.۰۱۳). Most events resulted in simple dislocations that were closed reduced successfully. BASD resulting from seizures or electrocutions were more likely to be fracturedislocations (P=۰.۰۱۸); and in younger patients with fracture-dislocations, closed reduction was more often to fail or not be attempted (P<۰.۰۵). Median follow-up was ۶ months (IQR: ۳ months – ۱۲ months). Seven patients (۱۰.۶%) had complications and ۴ (۲.۳%) demonstrated recurrent instability.Conclusion: In young males presenting with BASD without known trauma, suspicion should be high for a convulsantevent. In patients with a known seizure disorder who present with chronic bilateral shoulder or arm pain, BASD should be considered and work-up should be expedited to avoid misdiagnosis. Level of evidence: V

Bilateral, Dislocation, Instability, shoulder, Systematic review, Trauma