Computed tomography (CT) is the standard assessment of glenoid morphology before shoulder arthroplasty and is commonly used to evaluate rotator cuff pathology in patients with glenohumeral osteoarthritis (GHOA). Magnetic resonance imaging (MRI) is not routinely used in this setting but has higher sensitivity in diagnosing full-thickness rotator cuff tears (RCT) and is considered the gold standard. The purpose of this study was to determine the sensitivity and specificity of CT in diagnosing full-thickness RCTs and compare the evaluation of fatty infiltration and muscle atrophy on CT vs. MRI in the setting of GHOA.
In this retrospective case-controlled study, we identified 49 patients from a prospectively maintained 2-surgeon registry who received preoperative CT and MRI scans for the evaluation of GHOA between 2011 and 2016. Three fellowship-trained shoulder surgeons assessed rotator cuff integrity, fatty infiltration, and muscle atrophy in the CT and MRI scans.
CT sensitivity and specificity were 20% and 95.5%, respectively. Fatty infiltration was significantly lower on CT for the supraspinatus (P = .003), infraspinatus (P < .001), and subscapularis (P = .0182), whereas muscle atrophy was significantly lower on CT for only the supraspinatus (P = .0023).
Our results suggest that CT underestimates the frequency of full-thickness RCTs and the severity of fatty infiltration and muscle atrophy in the setting of GHOA before total shoulder arthroplasty.