Bilateral Anterior Shoulder Dislocation: A Systematic Review

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 1946-, Embase.com 1947-, Scopus 1960-, 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 (87 cases of BASD) were included. Patients were 41.1 (SD +/- 19.5) years old and most were male (n=63; 72.4%). Around a quarter of patients (28.7%) 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<0.05). Close to a third of cases (n=27; 31.0%) were delayed in presentation. Those sustaining seizures or electrocutions were more likely to be delayed in presentation (P=0.013). Most events resulted in simple dislocations that were closed reduced successfully. BASD resulting from seizures or electrocutions were more likely to be fracture-dislocations (P=0.018); and in younger patients with fracture-dislocations, closed reduction was more often to fail or not be attempted (P<0.05). Median follow-up was 6 months (IQR: 3 months - 12 months). Seven patients (10.6%) had complications and 4 (2.3%) demonstrated recurrent instability. Conclusion: In young males presenting with BASD without known trauma, suspicion should be high for a convulsant event. 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