The Accuracy of Magnetic Resonance Imaging and Magnetic Resonance Arthrogram Versus Arthroscopy in the Diagnosis of Subscapularis Tendon Injury

Purpose: The main purpose of this study was to evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in detecting subscapularis tears identified during the gold standard of arthroscopy and determine whether MRI can reliably predict which patients have subscapularis tears. A second purpose was to determine whether magnetic resonance (MR) arthrograms could better identify a subscapularis tear than conventional MRI. Methods: This was a retrospective study evaluating 39 consecutive patients (40 shoulders) who had a preoperative 1.5-T MRI study and underwent an arthroscopic subscapularis tendon repair. All cases were performed between December 2007 and November 2010. Results: Subscapularis tears were missed on preoperative MR scanning in 25 of 40 shoulders (62.5%). The sensitivity of noncontrast MRI was 40%, the sensitivity of MR arthrography was 36%, and the overall MR sensitivity was 37.5%. Conclusions: Preoperative 1.5-T MRI of the shoulder does not reliably predict subscapularis tendon tears, regardless of whether conventional MRI or MR arthrography is used. Level of Evidence: Level II, development of diagnostic criteria on basis of consecutive patients with universally applied gold standard.