Selective Prereduction Radiography in Anterior Shoulder Dislocation: The Fresno-Quebec Rule.

Background: Shoulder dislocation is one of the most frequent dislocations encountered by emergency physicians. Typical emergency care usually includes performing both prereduction and postreduction radiography. However, selective radiography has the potential benefits of reducing emergency department (ED) time and radiation exposure.

Objectives: To refine and combine two existing clinical decision rules for selective radiography in the ED management of anterior shoulder dislocation, thus creating the Fresno-Quebec rule (FQR).

Methods: Patients presenting to the ED with an anterior shoulder dislocation were enrolled in a prospective cohort study in two university-affiliated EDs. Patients with a clinically important fracture-dislocation were compared with those with an uncomplicated dislocation. We refined our new decision rule to detect all fracture-dislocations while maximizing specificity.

Results: A total of 207 patients were included in this study, of which 24 (11.8%) had a clinically important fracture-dislocation. The refined rule consisting of three criteria had a sensitivity of 100% (95% confidence interval [CI] 87.5-100%), specificity of 50% (95% CI 42.5-57.5%), negative predictive value of 100% (95% CI 96-100%), and a negative likelihood ratio of 0.21 (95% CI 0.14-0.30). No patient with an atraumatic, recurrent dislocation had a fracture. Patients over age 35 years had an increased risk of fracture-dislocation if they sustained blunt injury or had a first episode of dislocation. Using this rule could have reduced prereduction radiographs by 44%.

Conclusion: The refined Fresno-Quebec shoulder dislocation rule detected all clinically important prereduction fracture-dislocations and could have reduced prereduction films by 44%. Prospective validation is warranted.