Diagnostic Value of Clinical Tests for Infraspinatus Tendon Tears.

PURPOSE: To analyze and compare the diagnostic value and interpretation of 6 established clinical tests for infraspinatus tendon tears; to assess their ability to distinguish between partial- and full-thickness tears of the infraspinatus tendon; and to investigate whether conducting multiple tests increases the precision of diagnosis.

METHODS: A total of 91 patients scheduled for shoulder arthroscopy from March 2015 to April 2017 were included in the present study. To assess the sensitivity, specificity, positive and negative predictive values, accuracy, diagnostic odds ratio, positive and negative likelihood ratios, and the area under the curve (AUC), intraoperative findings were compared with the results of 6 established clinical infraspinatus tests: the hornblower's test, the drop sign, the Patte sign, the external rotation lag sign (ERLS), the resisted external rotation test (RERT), and the infraspinatus scapular retraction test.

RESULTS: A significant correlation was found between the results of the drop sign (P = .02), the ERLS (P = .02), and the RERT (P = .02) and the intraoperative findings. The RERT achieved the highest AUC (0.673). Assessing muscle weakness led to the highest diagnostic precision on the RERT (AUC = 0.673) as compared with pain (AUC = 0.528) or using both criteria (AUC = 0.655). No single clinical test was found to be useful in distinguishing between partial- and full-thickness tears. The combination of at least 2 or more tests improved the diagnostic precision significantly (P ≤ .007). The combination of the RERT and the Patte sign showed the best AUC (0.681) and highest correlation with the intraoperative findings (P = .023).

CONCLUSIONS: The results of the present study indicate that out of all the clinical tests investigated, the drop sign and the RERT were in isolation able to accurately diagnose tears of the infraspinatus tendon. Only muscle weakness should be considered when interpreting the RERT because of its greater AUC values and correlation with the arthroscopic findings. The present study also showed that the analyzed tests are not capable of distinguishing between partial- and full-thickness tears of the infraspinatus tendon and that the combination of at least 2 tests improved the diagnostic value. The combination of the RERT and the Patte sign showed the best AUC and highest correlation with the intraoperative findings.

LEVEL OF EVIDENCE: Level II, diagnostic study, prospective comparative study.