An analysis of the reports suggests that a number of factors play an important role in these discrepancies. The sonographic criteria, the patient population, and the desired information are crucial factors. In the postoperative patient, reports suggest that sonography is highly reliable. This may reflect the large size of recurrent tears. The reliability of the published criteria vary widely.
Most authors agree that failure to visualize the cuff has a high predictive value.
The least accurate finding is focally increased echogenicity. This may have several causes and should be used with caution, only when clear asymmetry exists between the shoulders. The patient population at a given center may also influence results. Patients in a referral center can be expected to have a higher prevalence of abnormalities and more advanced lesions. The inclusion of partial-thickness tears may also skew results.