COMPARISON OF EMPTY CAN TEST VERSUS FULL CAN TEST FOR DIAGNOSIS OF SUPRASPINATUS TEAR

Abstract

Background: Rotator cuff injuries, particularly supraspinatus tendon tears, are a prevalent cause of shoulder pain and dysfunction. Clinical diagnostic maneuvers such as the Empty Can Test (ECT) and Full Can Test (FCT) are commonly used to assess supraspinatus integrity, especially where imaging access is limited. However, their diagnostic accuracy, interobserver reliability, and patient tolerability remain variably reported.

Operational

Definitions: The Empty Can Test (ECT) and Full Can Test (FCT) are considered positive if they reproduce shoulder pain or weakness during resisted abduction in the scapular plane. Patient discomfort was recorded using the Visual Analogue Scale (VAS), ranging from 0 (no pain) to 10 (worst pain imaginable).

Methodology: This prospective diagnostic accuracy study included 60 adult patients with suspected rotator cuff pathology undergoing MRI. Each participant was assessed using both the ECT and FCT by two independent orthopedic examiners blinded to each other’s findings and MRI results. The tests were evaluated for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and interobserver reliability (Cohen’s kappa). Patient-reported discomfort during each test was measured using the Visual Analogue Scale (VAS).

Results: MRI confirmed supraspinatus tears in 65% of patients. The ECT demonstrated higher sensitivity (82.1%) but lower specificity (66.7%) compared to the FCT (sensitivity: 74.4%; specificity: 81.0%). Both tests had identical overall diagnostic accuracy (76.7%). Interobserver reliability was higher for the FCT (κ = 0.80) than the ECT (κ = 0.63). Patient-reported pain was significantly lower during the FCT (VAS: 4.1 ± 1.2) compared to the ECT (VAS: 5.9 ± 1.3, p < 0.001).

Conclusion: Although both tests show comparable diagnostic accuracy for detecting supraspinatus tears, the Full Can Test is superior in terms of specificity, interobserver reliability, and patient comfort. These findings support the use of the Empty Can Test as a sensitive screening tool and the Full Can Test as a more specific and patient-friendly confirmatory method. When used together and interpreted alongside imaging, they can enhance clinical assessment of rotator cuff pathology.