Interobserver Agreement in the Classification of Rotator Cuff Tears Using Magnetic Resonance Imaging

Background: Although magnetic resonance imaging (MRI) is a standard method of assessing the extent and features of rotator cuff disease, the authors are not aware of any studies that have assessed the interobserver agreement among orthopaedic sur-geons reviewing MRI scans for rotator cuff disease. Hypothesis: Fellowship-trained orthopaedic shoulder surgeons will have good interobserver agreement in predicting the more salient features of rotator cuff disease such as tear type (full thickness versus partial thickness), tear size, and number of ten-dons involved but only fair agreement with more complex features such as muscle volume, fat content, and the grade of partial-thickness cuff tears. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Ten fellowship-trained orthopaedic surgery shoulder specialists reviewed 27 MRI scans of 27 shoulders from patients with surgically confirmed rotator cuff disease. The ability to interpret full-thickness versus partial-thickness tears, acromion type, acromioclavicular joint spurs or signal changes, biceps lesions, size and grade of partial-thickness tears, acromiohumeral dis-tance, number of tendons involved and amount of retraction for full-thickness tears, size of full-thickness tears, and individual muscle fatty infiltration and atrophy were assessed. Surgeons completed a standard evaluation form for each MRI scan. Interobserver agreement was determined and a kappa level was derived