The diagnostic value of pre- and post-reduction radiographs in anterior shoulder dislocation

Determine the diagnostic characteristics of pre-reduction and post-reduction radiographs for bony lesions, identify associations between patient groups and bony lesions, and identify associations between the presence of certain bony lesions and others.

A retrospective consecutive sample of anterior shoulder dislocation patients ≥ 12 years old presenting to the emergency department of the OLVG (Amsterdam) between January 2022 and July 2023 was included. The sensitivity and negative predictive value (NPV) for bony lesions on pre-reduction and post-reduction radiographs were compared. A reference standard was established by considering a lesion present when observed at least once. Associations with lesions were expressed as phi-values and R-values.

Among 268 patients, the sensitivity and NPV of pre-reduction radiographs were lower compared to post-reduction radiographs for glenoid bone loss (sensitivity = 20-56% vs 61-92%; NPV = 91-94% vs 95-99%; n = 30) and bony Bankart lesions (sensitivity = 7-42% vs 91-94%; NPV = 68-94% vs 97-99%; n = 24). The 95% CI of pre-reduction radiographs were lower but had some overlap with post-reduction radiographs for Hill-Sachs lesions (sensitivity = 72-84% vs 80-90%; NPV = 60-72% vs 68-81%; n = 187), greater tubercle fractures (sensitivity = 76-96% vs 79-97%; NPV = 95-99% vs 96-99%; n = 45), and loose bodies (sensitivity = 13-65% vs 42-92%; NPV = 95-98% vs 97-99%; n = 14). Poor to very strong associations were identified between sex, age, and lesions with the presence of (other) lesions.

Post-reduction radiographs showed better diagnostic characteristics compared to pre-reduction radiographs for the identification of bony lesions. The age and sex of the patient and the presence of certain bony lesions were observed to be associated with the presence of (other) lesions.