An assessment of the interexaminer reliability of tests for shoulder instability Anthony Tzannes, BSc(Med), MBBS, Anastasios Paxinos, MBBS, FRACS, Mary Callanan, MBBS, and George A. C. Murrell, MBBS, DPhil, Sydney, Australia Accurate noninvasive clinical tests of shoulder instabil- ity are important in assessing and planning treatment for glenohumeral joint instability. An interexaminer agreement trial was undertaken to estimate the reliabil- ity of commonly used clinical tests for shoulder instabil- ity. Thirteen patients with a history suggestive of insta- bility, who had been referred to a shoulder specialist for treatment of their symptomatic shoulders, were ex- amined by four examiners of differing experience. Good to excellent interexaminer agreement was found for most variations of the load-and-shift test, with the best agreement in the 90° abducted position for the anterior direction (intraclass correlation coefficient [ICC] = 0.72) and in the 0° abducted position for the posterior (ICC = 0.68) and inferior (ICC = 0.79) di- rections. Fair to good interexaminer reliability was found for the sulcus sign (ICC = 0.60). With regard to the provocative tests, agreement was best when appre- hension was used as the criterion for a positive test and was better for the relocation (ICC = 0.71) and release tests (ICC = 0.63) than for the apprehension (ICC = 0.47) and augmentations tests (ICC = 0.48). Reliability was poor (ICC  0.31) when pain was used as the criterion for a positive test. These results indicate that the load-and-shift, sulcus, and provocative tests (apprehension, augmentation, relocation, and release) are reliable clinical tests for instability in symptomatic patients when care is taken with respect to arm positioning and if apprehension is used as the criterion for a positive provocative test. (J Shoulder Elbow Surg 2004;13:18-23.) T he glenohumeral joint is the most commonly dislo- cated joint. Dislocation most frequently occurs in the anterior direction when the arm is forcibly abducted and externally rotated, and it is usually painful and disabling. Dislocations can also occur posteriorly, inferiorly, or in multiple directions and often require surgical intervention. Excess glenohumeral joint trans- lation, without frank dislocation, can be asymptom- atic but can also cause symptoms and impair perfor- mance. A number of clinical tests have been described to assess glenohumeral joint translation and to reproduce or provoke symptoms of glenohu- meral joint instability. If the results of these tests are to be valuable for clinical prediction and screening, they must be both valid and reliable. Validity (lack of systematic error bias) is defined as the extent to which a measure correctly evaluates the desired trait. Valid- ity was not addressed in this study. Reliability is defined as the extent to which a measure is repeat- able and, therefore, represents the degree of nonsys- tematic error. Reliability can be estimated from mea- surements made by different raters on the same material (agreement). Two types of agreement can be distinguished according to whether one rater makes two or more measurements on the same material (intraexaminer) or whether each of several raters independently measures the same material (interex- aminer). The purpose of this study was to determine the intraexaminer reliability of 13 clinical tests for shoul- der instability. MATERIALS AND METHODS The subjects included in this study were (1) patients whose shoulder was sufficiently symptomatic to warrant referral to an orthopaedic shoulder specialist and (2) those whose history was suggestive of or suspicious for glenohu- meral joint instability. Patients were excluded if (1) there was a history of previous surgery or (2) they had significant loss of glenohumeral joint motion (ie, they had less than 30° external rotation, less than 90° forward flexion, or less than 90° abduction or could internally rotate their arm to no greater than L5). 4 There were 25 patients who met the inclusion criteria for this study. Of these, 12 were excluded because the shoul- der was too painful to be examined by all 4 examiners or From the Sports Medicine and Shoulder Service, Orthopaedic Research Institute, St George Hospital Campus, University of New South Wales. Funded by the St George Hospital/South Eastern Sydney Area Health Service. Reprint requests: George A. C. Murrell, MBBS, DPhil, Department of Orthopaedic Surgery, St George Hospital Campus, University of New South Wales, Kogarah, Sydney, 2217, NSW, Australia (E-mail: murrell.g@ori.org.au). Copyright © 2004 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2004/$35.00 + 0 doi:10.1016/j.jse.2003.09.002 18