HAGL Tears in traumatic instability – Detection on MR-Arthrogram
Authors: R Saqib, J Harris, L Funk
Background: Humeral avulsion of the glenohumeral ligaments (HAGL) is a recognised cause of shoulder instability and can be isolated or in conjunction with other abnormalities such as labral tears, rotator cuff tears or Hill-Sachs lesions. Biomechanical cadaveric studies suggest that the inferior glenohumeral ligament would fail at the humeral insertion in as many as 25% of cases.1 However, clinical series suggest a lower incidence of HAGL ranging from 2.4% to 9.3% of patients undergoing arthroscopy for anterior instability. 2,3,4 No previous study has correlated the incidence of HAGL on MR-Arthrogram (MRA) with arthroscopy.
Aims: Our aim was to assess the accuracy of MRA in detecting HAGL tears compared with arthroscopy.
Methods: 122 patients with pre-operative MRA underwent arthroscopic surgery for instability in a 1-year period. All scans were reviewed by senior musculoskeletal radiologists and an experienced shoulder surgeon. All arthroscopies were performed by a single surgeon and HAGL tears were specifically recorded.
Results: The incidence of HAGLs was 5% on both arthroscopy and MRA. The sensitivity of MRA in detecting HAGL was 0.66 and the specificity was 0.33. The positive predictive value was 0.66 and negative predictive vale was 0.33.
Conclusions: MRA appears to be sensitive in detecting HAGL, but not specific. This may be due to associated soft tissue oedema seen on MR with early scans after injury.
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