Clinical Assessment of the Dynamic Labral Shear Test for Superior Labrum Anterior and Posterior Lesions

Background: Diagnosing superior labrum anterior and posterior (SLAP) lesions through physical examination remains challenging. The dynamic labral shear test (DLST) has been shown to have likelihood ratios (LRs) of 31.6 and 1.1 for diagnosing SLAP lesions. Purpose: To determine the clinical utility of the DLST for diagnosing SLAP lesions. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: This prospective, consecutive case series included 774 patients who underwent diagnostic arthroscopy and a preoperative DLST between 2007 and 2013. Patients were divided into 3 groups: 610 control patients with no SLAP lesion but with other abnormalities, 9 patients with isolated SLAP lesion (ISL), and 155 patients with concomitant SLAP lesion (CSL), who had a SLAP lesion and another shoulder abnormality. We determined sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), odds ratio (OR), and diagnostic accuracy (DA) of the DLST with and without other tests. Results: The DLST was positive for 242 of 610 controls (40%), 7 of 9 patients (78%) in the ISL group, and 88 of 155 patients (57%) in the CSL group. In the ISL group, the DLST had a sensitivity of 78%, specificity of 51%, PPV of 2%, NPV of 100%, OR of 3.58, and DA of 51%. In comparison, the ORs were 1.09 for the active compression test, 1.30 for the lift-off test, and 1.53 for the relocation test, which were not significantly different from each other. For diagnosing a SLAP lesion existing in a joint with other associated injury, the DLST had a sensitivity of 57%, specificity of 52%, PPV of 23%, NPV of 83%, OR of 1.4, and DA of 53%. Combining all 4 tests did not improve the OR for detecting ISLs or CSLs. Conclusion: The DLST is sensitive but not specific for detecting ISLs. With an OR of 3.58, the DLST is useful for diagnosing ISLs. However, in patients who have CSLs, the DLST is not as useful for diagnosing SLAP lesions.