Development and External Validation of a Clinical Decision Rule for Excluding Shoulder Fractures: A Prospective Multicentre Diagnostic Accuracy and Cost-Effectiveness Study (SFER Study)

Abstract Shoulder trauma is a common presentation in orthopedic and emergency settings and frequently leads to routine radiographic imaging despite a relatively low prevalence of fractures. This practice contributes to increased healthcare costs, unnecessary radiation exposure, and inefficiencies in patient flow. Currently, no validated clinical decision rule exists to safely exclude shoulder fractures. We will conduct a prospective, multicentre diagnostic accuracy study in a high-volume orthopedic setting, enrolling approximately 1200 adult patients presenting with acute shoulder trauma. The study will include derivation and external validation cohorts. All participants will undergo standardized clinical assessment using the SFER clinical decision rule, followed by radiographic imaging as the reference standard. The primary outcome is sensitivity for fracture detection, with secondary outcomes including specificity, negative predictive value, reduction in imaging rates, missed fracture rate, inter-rater reliability, and cost-effectiveness. We hypothesize that the SFER rule will achieve sensitivity ≥95% with a missed fracture rate <1%, enabling safe reduction of unnecessary imaging and improving clinical efficiency.