Reliability of Radiographic Parameters in the Evaluation of Scapholunate Dissociation.

Abstract

Accurate and reliable radiographic measurement is essential to diagnose and evaluate surgical treatment outcomes for scapholunate dissociation (SLD). Although published standards for measuring radiographic parameters have demonstrated excellent interrater and intrarater reliability in normal patients, we were unable to find reliability data for patients with SLD. We hypothesized that six radiographic parameters for SLD would have good reliability in normal and injured patients. Wrist radiographs of patients with SLD and a control group of uninjured patients seen at our institution from 2017 to 2020 were reviewed. Radiographs were randomized, anonymized, and evaluated by five raters. A standardized measurement algorithm for each radiographic parameter was developed based on modified Larsen criteria, taught to each reader in repeated group and individual learning sessions and in a video. Raters measured scapholunate gap, radiolunate angle, radioscaphoid angle, scapholunate angle, radio-third metacarpal angle, and dorsal scaphoid translation (DST). Intraclass correlation coefficient (ICC) measurements were conducted using a two-way random effects model for interrater reliability and a two-way mixed effects model for intrarater reliability. Thirty-two radiographic sets were reviewed by each rater. Scapholunate gap, radiolunate angle , radioscaphoid angle, scapholunate angle, and radio-third metacarpal angle demonstrated "good" to "excellent" interrater and mean intrarater reliability. Although DST was found to have good intrarater reliability (mean ICC = 0.85), interrater reliability was found to be only moderate (ICC = 0.57). Using a standardized measurement technique, five of six common SLD radiographic parameters demonstrated good-to-excellent interrater and intrarater reliability. DST was the only parameter to demonstrate moderate interrater reliability, highlighting the need for a more reproducible measurement technique to better assess scaphoid dorsal translation in patients with SLD. Future diagnostic and clinical outcome studies of SLD should use standardized techniques to measure six common radiographic parameters.