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

There are a huge number of clinical tests for assessing postero-superior cuff tendon function and therefore to hypothesize their inflammation or tear. Summarizing, these tests may be classified in four groups: 1) those able to reproduce shoulder pain when the distance between greater tuberosity and coraco-acromial arch decreases during forward flexion or internal rotation (Neer; Hawkins); 2) those that assess cuff muscles strength (Jobe; full-can; Patte; etc.): 3) those where the examinator appreciates the possibility that a common gesture may be performed (hornblower's sign) and LAG signs (ERLS and DROP). The purpose of this study was to assess the diagnostic accuracy of a new test of resistance for the diagnosis of impingement syndrome and full thickness postero-superior rotator cuff tears. Material: one hundred and twenty patients consecutively undergoing shoulder arthroscopy for diagnoses related to shoulder pain and weakness (impingement syndrome and postero-superior cuff tears) were clinically evaluated. The study group consisted of 46 patients with inpingement syndrome and 74 with a cuff tear (53 supraspinatus and 21 supraspinatus + infraspinatus). The patient age ranged from 46 to 79 (mean age 64.2). The test of resistance is performed in the standing position with the involved arm in 90° abduction, 20°-30° 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 center to the end of the spiral and vlceversa (spiral width= 20 cm). After 10 turns we allowed patients to rest for 1 minute. The spiral is coloured red and blue to limit visual problems consequent to action repetitivity. The test was considered positive when the patient was not able to conclude it due to strength decrease or to shoulder pain. when the test resulted positive, we considered the number of turns performed. Results were compared with the contralateral normal arm. Data were tabulated and sensitivity. specificity, positive and negative predictive values as well as diagnostic accuracy were calculated for our test of resistance. Results: Test of resistance: For subacromial lmpigment: Sensitivity 57 %; Specificity 98%; Positive Predictive value 94%; Negative Predictive value 64%; Diagnostic Accuracy 69%. For Cuff Tear (in general): Sensitivity 65%; Specificity 98%; Positive Predictive Value 98%; Negative Predictive Value 66%; Diagnostic Accuracy 79%. Supraspinatus Tear: Sensitivity 55%; Specificity 98%; Positive Predictive Value 97%; Negative Predictive Value 58%; Diagnostic Accuracy 76%. Supraspinatus + lnfraspinatus rear: sensitivity 91%; Specificity 98%; Positive Predictive Value 95%; Negative Predictive Value 96%: Diagnostic Accuracy 96%. Conclusion: Our test is scarcely reliable as detector of subacromial impingement and not very reliable as a detector of a small tear; when the test of resistance results positive there is a high probability that subacromial disease exists. Finally, when the test results negative there is a high probability that the patient has not a large or massive cuff tear. ln conclusion, the resistance test (Gum-Turn test) adds to our armamentarium of physical examination signs in patients with painful shoulder.