A positive tangent sign predicts the repairability of rotator cuff tears

Abstract

We hypothesize that patients with a positive tangent sign will have rotator cuff tears that are not able to be repaired primarily. We performed a retrospective review of the charts of patients who had undergone surgery for repair of a rotator cuff tear. The operative note was reviewed to determine whether the cuff tear was primarily repaired. The magnetic resonance imaging study of each patient was reviewed to assess for a positive or negative tangent sign. The reviewer was blinded to the result of each measurement. Eighty-one patients met the inclusion criteria. Of the 79 included in our analyses, 17 had a positive tangent sign and 62 had a negative tangent sign. There was only 1 patient with a negative tangent sign who had an irreparable rotator cuff tear. There were 3 patients with a positive tangent sign who had a repairable rotator cuff. With a pretest prevalence of irreparable tears of 18.9%, a positive finding suggested a post-test probability of 82.3% with a positive tangent sign and a post-test probability of only 1.6% when the tangent sign was negative. Our results showed decision-making value in both a negative tangent sign and a positive tangent sign. The tangent sign is an easily performed and reproducible tool with good intraobserver and interobserver reliability that is a powerful predictor of whether a rotator cuff tear will be repairable.