Interobserver and intraobserver comparison of imaging glenoid morphology, glenoid version and humeral head subluxation

Background: Glenoid morphology, glenoid version and humeral head subluxation represent important parameters for the treating physician. The most common method of assessing glenoid morphology is the Walch classification which has only been validated with computed tomography (CT). Methods: CT images and magnetic resonance imaging (MRI) images of 25 patients were de-identified and randomized. Three reviewers assessed the images for each parameter twice. The Walch classification was assessed with a weighted kappa value. Glenoid version and humeral head subluxation were comparted with a reproducibility coefficient. Results: The Walch classification demonstrated almost perfect intraobserver agreement for MRI and CT images (k = 0.87). Weighted interobserver agreement values for the Walch classification were fair for CT and MRI (k = 0.34). The weighted reproducibility coefficient for glenoid version measured 9.13 (CI 7.16–12.60) degrees for CT and 13.44 (CI 10.54–18.55) degrees for MRI images. The weighted reproducibility coefficient for percentage of humeral head subluxation was 17.43% (CI 13.67–24.06) for CT and 18.49% (CI 14.5–25.52) for MRI images. Discussion: CT and MRI images demonstrated similar efficacy in classifying glenoid morphology, measuring glenoid version and measuring posterior humeral head subluxation. MRI can be used as an alternative to CT for measuring these parameters. Keywords Glenoid morphology, glenoid version, Walch classification, humeral head subluxation