Computed Tomography and Magnetic Resonance Imaging Are Similarly Reliable in the Assessment of Glenohumeral Arthritis and Glenoid Version

The purpose of this study was to compare the intra- and inter-observer reliability of CT and T2-weightedMRI for evaluation of the severity of glenoid wear, glenohumeral subluxation, and glenoid version. Sixty-one shoulders with primary osteoarthritis had CT and MRI scans before shoulder arthroplasty. Allslices were blinded and randomized before evaluation. Two fellowship-trained shoulder surgeons and three orthopaedicsurgery trainees reviewed the images to classify glenoid wear (Walch and Mayo classifications) and glenohumeralsubluxation (Mayo classification). Glenoid version was measured using Friedman’s technique. After a minimum twoweekinterval, the process was repeated. Intraobserver reliability was good for the CT group and fair-to-good for the MRI group for the Walch, Mayoglenoid, and Mayo subluxation classifications; interobserver reliability was poor for the CT and fair-to-poor for the MRIgroup. For the measurement of glenoid version, intraobserver reliability was good the CT and substantial for the MRIgroup; interobserver agreement was good for both groups. There were no significant differences in reliability betweenstaff surgeons and trainees for any of the classifications or measurements. CT and MRI appear similarly reliable for the classification of glenohumeral wear patterns. For themeasurement of glenoid version, MRI was slightly more reliable than CT within observers. Differences in traininglevel did not produce substantial differences in agreement, suggesting these systems can be applied by observers ofdifferent experience levels with similar reliability.Level of evidence: III