Empty can and drop arm test in cuff rupture: Improved specificity after subacromial injection

Abstract

 This study tries to validate the empty can test and drop arm test for cuff-rupture when assessed before and after subacromial injection of a corticosteroid with lidocain against ultrasound. Methods 50 Patients with subacromial impingement entered the study. During examination the empty can test and drop arm test were assessed. Patients received a subacromial injection and empty can and drop arm test and were reassessed. Results On ultrasound 6 cuff ruptures were found. Sensitivity of the empty can test decreased, whereas specificity improved. The sensitivity of the drop arm test did not change after injection whereas specificity improved after injection. Combining the tests resulted in an decrease in sensitivity and increase in specificity after injection.   Conclusions Specificity of the empty can and drop arm test increase after injection, while sensitivity remains the same. Combined results of empty can and drop arm test show intermediate sensitivity and high specificity without injection and low sensitivity and high specificity after injection.