Upright versus supine radiographs of clavicle fractures: does positioning matter?

OBJECTIVES: To determine whether clavicle fracture displacement and shortening are different between upright and supine radiographic examinations.
DESIGN: Combined retrospective and prospective comparative study.
SETTING: Level I Trauma Center. PATIENTS: Forty-six patients (mean age, 49 years; range, 24-89 years) with an acute clavicle fracture were evaluated. INTERVENTION: Standardized clavicle radiographs were obtained in both supine and upright positions for each patient. Displacement and shortening were measured and compared between the 2 positions. MAIN OUTCOMES MEASUREMENTS: One resident and 3 traumatologists classified the fractures and measured displacement and shortening. Data were aggregated and compared to ensure reliability with a 2-way mixed intraclass correlation.
RESULTS: Fracture displacement was significantly greater when measured from upright radiographs (15.9 ± 8.9 mm) than from supine radiographs (8.4 ± 6.6 mm, P < 0.001), representing an 89% increase in displacement with upright positioning. Forty-one percent of patients had greater than 100% displacement on upright but not on supine radiographs. Compared with the uninjured side, 3.0 ± 10.7 mm of shortening was noted on upright radiographs and 1.3 ± 9.5 mm of lengthening on supine radiographs (P < 0.001). The intraclass correlation was 0.82 [95% confidence interval (CI), 0.73-0.89] for OTA fracture classification, 0.81 (95% CI, 0.75-0.87) for vertical displacement, and 0.92 (95% CI, 0.88-0.95) for injured clavicle length, demonstrating very high agreement among evaluators.
CONCLUSIONS: Increased fracture displacement and shortening was observed on upright compared with supine radiographs. This suggests that upright radiographs may better demonstrate clavicle displacement and predict the position at healing if nonoperative treatment is selected.