Diagnostic value of four clinical tests for the evaluation of subscapularis integrity

Abstract

The lift-off, internal rotation lag sign, belly-press, and bear-hug tests are widely used toevaluate the integrity of the subscapularis. We hypothesized that these tests might reflect different types of subscapularis tears and sought to ascertain whether these tests accurately determine the severity of the internal rotation strength deficit and fatty degeneration. Isokinetic testing and the 4 clinical tests were used preoperatively to evaluate 312 patients who had undergone arthroscopic rotator cuff surgery. Of these, 37 patients had a full-thickness subscapularis tear, 96had a partial-thickness tear, and 179 had no tear. For differentiating any tears from an intact subscapularis, the most sensitive test was the belly-press test (27.8%), and the most specific test was the lift-off test (100%). For differentiating a full-thickness tear from a partial tear, the most sensitive test was the belly-press test (56.8%), and the most specific was the lift-off test (96.9%). A positive lift-off test also most reflected loss of internal rotation strength (mean, 72.2%; 95% confidence interval, 61.9-82.5), followed by the internal rotation lag sign (55.1%; 44.2-66.1) and the belly-press test (45.9%; 36.4-54.4). A positive lift-off test was highly specific for the detection of a full-thickness subscapularis tear and to reflect severe fatty degeneration. The lift-off, internal rotation lag sign, belly-press, and bear-hug tests sequentially predict internal rotation strength deficit and provide discrimination of internal rotation strength impairment.