A new test of resistance in the diagnosis of postero-superior rotator cuff tears.

The aim of this study was to assess the diagnostic accuracy of a new clinical test for the diagnosis of subacromial impingement and full thickness postero-superior rotator cuff tears. One hundred and twenty patients who underwent arthroscopic treatment for acromioplasty or cuff repair were previously submitted to a new test of resistance. The test is performed in the standing position with the involved arm in 90 degrees abduction, 20 degrees -30 degrees anteposition and in external rotation (as for full-can test). Thus, the patient was invited to follow the way of a spiral drawn on a drawing sheet for 20 turns; 1 turn = from the centre to the end of the spiral and vice versa (spiral width = 20 cm). The test was considered positive when the patient was not able to conclude it due to strength decrease or to shoulder pain. Sensitivity, specificity, positive and negative predictive values as well as diagnostic accuracy were calculated for our test of resistance. The test resulted scarcely reliable as detector of subacromial impingement and not very reliable as detector of small tear. When the test is positive there is a high probability that a subacromial disease exists; instead, when it is negative there is a high probability that the patient has not a large or massive cuff tear. The resistance test (Gum-Turn test) adds to our armamentarium of physical examination signs in patients with painful shoulder and furnishes further information on possible dimensions of tendinous tear.