Accuracy of ultrasonography and magnetic resonance imaging for detection of full thickness rotator cuff tears

Background: Rotator cuff problems are frequently seen by orthopedic surgeons and accurate diagnosis is essential for appropriate management. Value of the clinical assessment of a shoulder is often limited, therefore, imaging studies have important implications in the management of rotator cuff pathologies. Aim: The purpose of this retrospective study is to compare the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) for detection of full-thickness rotator cuff tears. Materials and Methods: We reviewed 91 consecutive cases of shoulder arthroscopy and open rotator cuff repair, who had undergone preoperative investigation in the form of either an ultrasound or MRI. Thirty-six patients had an ultrasound and 55 had an MRI for their affected shoulders. We compared the accuracy of US and MRI for detection of full-thickness rotator cuff tears, using the operative findings as the gold standard. Data regarding a supraspinatus tear was assessed for the purpose of this study. Results: Ultrasonography correctly diagnosed 15 out of 17 tears (sensitivity of 0.88). There were 17 true-negative and two false-positive ultrasounds (specificity of 0.89). MRI accurately identified 33 of the 36 tears (sensitivity of 0.91). There were 16 true-negative and three false-positive tears on MRI (specificity of 0.84). The positive predictive value (PPV) was 88 for US and 92 for MRI. The negative predictive value (NPV) was 89 for US and 84 for MRI. The overall accuracy of the ultrasound was 88.89 (95 confidence interval (CI) = 74.09 to 96.18) as compared to 89.09 (95 CI = 77.82 to 95.26) for the MRI. Conclusion: Full-thickness rotator cuff tears can be identified using ultrasound and MRI with comparable accuracy. US being a dynamic study and better tolerated by the patient, can therefore be used as the first-line investigation for rotator cuff tear, where appropriate skills are available to reduce the waiting time and cost of investigation.