A new, effective method for diagnosing GLAD lesions: the chicken-wing muscle up test

Purpose: We aimed to develop and evaluate a new diagnostic method, the 'chicken-wing muscle up test', to improve the accuracy of diagnosis of glenolabral articular disruption (GLAD) lesions compared to currently used clinical tests for injuries to the labrum.

Methods: Preoperative evaluations were conducted on 85 patients undergoing arthroscopic surgery at a single center between July 2021 to July 2022. The diagnostic performance of the preoperative clinical examinations (chicken-wing muscle up test, O'Brien test, crank test, and O'Driscoll test) were validated against the findings of arthroscopic examinations.

Results: 12 of the 85 patients in this study had arthroscopically confirmed GLAD lesions. The chicken-wing muscle up test demonstrated significantly higher sensitivity (83.33%) for GLAD lesions than the O'Brien test (33.33%), but not the crank test (50.00%) or O'Driscoll test (25.00%), and significantly higher specificity (95.89%) than the O'Brien test (75.34%), crank test (82.19%), and O'Driscoll test (71.23%). The chicken-wing muscle up test had the largest area under the receiver operating characteristic curve (AUC = 0.896, P < 0.001; O'Driscoll test AUC = 0.543, P > 0.05; crank test AUC = 0.661, P > 0.05; O'Brien test AUC = 0.481, P > 0.05), indicating significantly better diagnostic efficacy for GLAD lesions than the other three tests.

Conclusions: The chicken-wing muscle up test is a reliable diagnostic method that improves the accuracy of diagnosis of GLAD lesions.