Comparison of dynamic sonography to stress radiography for assessing glenohumeral laxity in asymptomatic shoulders

BACKGROUND: Stress radiography has been the established imaging method for quantifying glenohumeral joint laxity. Dynamic ultrasound is an alternative imaging method that may be used to measure glenohumeral laxity; however, validity and repeatability have not been examined. OBJECTIVE: To determine criterion-related validity and repeatability of a sonographic imaging method for measuring glenohumeral laxity in asymptomatic shoulders. STUDY DESIGN: Controlled laboratory study. METHODS: In experiment 1, 20 subjects were assessed for glenohumeral laxity using stress radiography and dynamic ultrasound. In the second experiment, 13 subjects were assessed for laxity in 2 separate test sessions using the dynamic ultrasound technique. RESULTS: Correlational analysis between the sonographic and radiographic measures revealed an r = 0.79 (r(2) = 0.62), indicating excellent criterion-related validity for the sonographic imaging method. Test-retest repeatability was 0.72 and 0.85 for anterior and posterior translation, respectively, and interrater repeatability was 0.96 and 0.99 for anterior and posterior translation, respectively. CONCLUSIONS: Dynamic ultrasound appears to be a valid and repeatable method for assessing glenohumeral laxity in a clinical setting. CLINICAL RELEVANCE: Based on the results of this study, dynamic ultrasound is a repeatable and valid method for measuring glenohumeral laxity and therefore may be used as a viable replacement for stress radiography during assessments of glenohumeral laxity.