A recently published diagnostic test accuracy (DTA) review evaluates magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA) and ultrasonography for assessing rotator cuff tears in people with shoulder pain for whom surgery is being considered. Tears in the rotator cuff, a group of tendons and muscles that surrounds the shoulder, cause pain and may impair shoulder stability and movement. They are often graded as partial thickness or full thickness . The review compares the three index tests with assessment during surgery, usually arthroscopic (keyhole) surgery. Arthroscopy is an imperfect reference test, with all the disadvantages inherent in surgery as well as between-rater variation in the classification of tears.