Introduction Little is understood about the relationship between delay to treatment and initial reduction success for anterior shoulder dislocation. Our study examines whether delays to initial treatment, from injury and hospital presentation, are associated with higher reduction failure rates for anterior shoulder dislocation.

Methods A retrospective database and chart review was performed for patients undergoing intravenous sedation for attempted reduction of anterior shoulder dislocation in the emergency department (ED). Stepwise regression analysis was performed to identify predictors of reduction failure. Key variables analysed were the duration of the wait in the ED, the interval between the time of injury and first intervention and the interval from time of injury to arrival at the ED. Possible confounding variables analysed included age, gender, dose of sedative agent, qualifications of the reducing physician and whether the dislocated shoulder was recurrent.

Results The duration of the intervals from injury to first reduction attempt and from arrival at the ED to first reduction attempt were both independent predictors of a higher reduction failure rate (OR=1.07, 95% CI 1.02 to 1.13; OR=1.19, 95% CI 1.05 to 1.34). Every interval of 10 min increased the odds of a failed reduction attempt by 7% and 19%, respectively. Overall, shoulder reduction was successful during the initial sedation event in 97 cases (92%) and unsuccessful in nine cases (8%).

Conclusions Delays to first reduction attempt either from the time of injury or within the ED are associated with a lower reduction success rate for anterior shoulder dislocations.