Detection of Rotator Cuff Tears by Ultrasound: How Many Scans Do Novices Need to Be Competent?

BACKGROUND: Ultrasound is commonly used for evaluating rotator cuff tears. However, little training in ultrasound imaging is provided during orthopedic residents’ training period. Therefore, we performed this study to determine how many ultrasound scans are required for orthopedic residents to be competent and self-confident in the diagnosis of supraspinatus tendon tears and to investigate whether senior residents outperformed junior residents. METHODS: We studied two third-year residents who had no previous experience of shoulder ultrasound and evaluated their ability to detect rotator cuff pathologies. Their learning curves were plotted using a cumulative summation analysis with a 20% acceptable failure rate compared to arthroscopic findings. Downward, upward, and horizontal cumulative summation trends indicated incompetence, exceptional competence, and competence, respectively. The diagnostic accuracy of third-year residents was compared with that of second-year residents and the number of cases required to gain self-confidence was evaluated. RESULTS: Cumulative summation analysis showed that after 26–28 scans, residents achieved the competence to correctly diagnose supraspinatus tears: an upward trend was observed from the beginning for full-thickness tears and a downward trend was observed for partial-thickness tears. Sensitivity and specificity were 0.95 and 0.79, respectively, for third-year residents and 0.91 and 0.58, respectively, for second-year residents. Residents reported self-confidence after 30 ultrasound scans for the detection of rotator cuff tears. CONCLUSIONS: The number of scans that novices needed to be competent for detecting rotator cuff tears was approximately 30 cases, and the diagnostic accuracy of third-year residents was significantly higher than that of second-year residents.