Humeral avulsion of glenohumeral ligaments – Detection on magnetic resonance arthrography

BackgroundHumeral avulsion of the glenohumeral ligaments (HAGL) is an important cause of shoulder instability, with magnetic resonance arthrography (MRA) routinely being used for diagnosis. Our aim was to compare the diagnostic value of MRA to shoulder arthroscopy for the detection of HAGL lesions and to calculate its prevalence.MethodsPatients who underwent a shoulder arthroscopy with a single surgeon and pre-operative MRA between February 2011 and March 2012 for instability were identified. MRAs were reported by experienced musculoskeletal radiologists and compared to arthroscopy findings for the presence of HAGL lesions. Sensitivity, specificity, positive and negative predictive values, prevalence and positive and negative likelihood ratios were calculated.ResultsA total of 194 patients were identified with a HAGL lesion prevalence of 4.64% on arthroscopy. The sensitivity of MRA in detecting HAGL was 0.44 (CI: 0.14–0.79) and the specificity was 0.97 (CI: 0.94–0.99). The positive predictive value was 0.44 (CI: 0.14–0.79) and negative predictive value was 0.97 (CI: 0.94–0.99). The positive likelihood ratio was 16.44 (CI: 5.30–51.00) and negative likelihood ratio was 0.57 (CI: 0.32–1.02).ConclusionsMRA appears to be specific and accurate in excluding HAGL lesions, but not sensitive. HAGLs were associated with numerous other injuries such as bankart, SLAP and Hill–Sach lesions. The prevalence of 4.64% is comparable to previous studies.