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.