Lateral Stress Radiographs of Lateral Compression Type 1 Pelvic Injuries, With the Injured Side Down or Up, Reliably Measure Occult Instability. Issue 10 (October 2022)

• Record Type: Journal Article
• Authors: Parry, Joshua A.; Hadeed, Michael M.; Strage, Katya E.; Heare, Austin; Stacey, Stephen C.; Mauffrey, Cyril
• Is Part Of: Journal of orthopaedic trauma. Volume 36:Issue 10(2022)
• Page Start: 494
• Page End: 497
• Publication Date: 2022-10
• Subjects: lateral compression pelvic ring injury -- LC1 -- instability -- examination under anesthesia -- lateral stress radiographs -- complete -- incomplete sacral fracture -- injured side down; Orthopedics -- Periodicals; Wounds and injuries -- Periodicals; Orthopedics -- Periodicals; Wounds and Injuries -- therapy -- Periodicals; Periodicals; 617.47044
• DOI: 10.1097/BOT.0000000000002374
• Languages: English
• ISSNs: 0890-5339

Abstract

Abstract : Objectives: To evaluate the interobserver reliability of measured displacement and occult instability of minimally displaced lateral compression type 1 (LC1) fractures on lateral stress radiographs (LSRs) and to compare differences in displacement between LSR with the injured side down (ID) and up (IU). Design: Retrospective review. Setting: Urban Level 1 trauma center. Patients/Participants: Twenty-three adult patients with minimally displaced (<1 cm) LC1 injuries. Intervention: None. Main Outcome Measurements: Three orthopaedic surgeons measured the distance between the radiographic teardrops on LSR and supine anteroposterior pelvic radiographs to calculate dynamic fracture displacement. The interobserver reliability of the measured displacement, a continuous variable, was assessed by calculating the intraclass correlation coefficient. The interobserver reliability of occult instability (≥10 mm of displacement on LSR), a categorical variable, was assessed by calculating the kappa value. Matched-pairs analysis was performed to calculate the mean difference of measurements between observers and between ID and IU LSR. Results: The interobserver reliability of the measured displacement was excellent (intraclass correlation coefficient 0.93). The mean difference in measurements between observers ranged from −1.8 to 0.96 mm. The mean difference in the measured displacement between ID and IU LSRs for each observer ranged from −0.6 to 0.3 mm. There was 83% (19/23 cases) agreement on the presence of occult instability (≥10 mm of displacement on LSR) on both ID and IU LSRs. The interobserver reliability of occult instability was moderate (kappa 0.76). Conclusions: Measured fracture displacement and occult instability of minimally displaced LC1 injuries were reliably measured and identified on LSR, regardless of the laterality.