Abstract
In previously published work, MR arthrogram (MRA) has sensitivities and specificities of 88–100% and 89–93% respectively in detection of glenoid labrum tears. Our practice suggested higher frequency of falsely negative reports. We aimed to assess accuracy of this costly modality in practice.
We retrospectively reviewed MRA reports of 90 consecutive patients with clinical shoulder instability who had undergone arthroscopy. All had history of traumatic anterior dislocation and had positive anterior apprehension tests. All underwent stabilisation during the same procedure. We compared the findings, using arthoscopy as gold standard in identification of glenoid labral tears.
83/90 patients had glenoid labrum tears at arthroscopy. Only 54 were correctly identified at MRA. All normal labra were identified. This gave sensitivity of 65% and specificity of 100% in identification of all types of glenoid labrum tear. The majority had anterior glenoid labral tears, which were detected at an even lower rate of sensitivity (58%).
Sensitivity of MRA in this series is significantly lower than previously published. This study highlights the importance of an accurate history and clinical examination by specialist shoulder surgeons in the management of glenohumeral instability. The need for this costly investigation may not be as high as is currently the case.
