Magnetic Resonance Arthrography in Assessment of Glenohumeral Labroligamentous Injuries, Revisited with Emphasis on Challenges and Added Value of Abduction External Rotation Position

Background: The glenohumeral joint is the most common joint to become unstable and get dislocated. MRI and MR ar-thrography are the mainstay diagnostic imaging modality re-quested for preoperative planning. Aim of Study: The aim of this study was to assess the di-agnostic value of direct MRA, with inclusion of an additional Abduction and External Rotation (ABER), in evaluation of dif-ferent labrum and ligamentous injuries, using arthroscopy as the gold standard. Patients and Methods: An observational, analytical, and prospective study which included 92 patients, for whom MRI and MR ARTHROGRAPHY with additional ABER was done and the imaging results were compared to arthroscopy as gold standard. Results: MRI and MR ARTHROGRAPHY with additional ABER revealed 49 labrum injuries, 6 ligamentous injuries and 3 capsular injuries. Other findings included 5 biceps/labrum anchor tear, 17 rotator cuff pathologies, 12 Hill Sachs and 2 reverse Hill Sachs injuries. The labral injuries: 24 anterior infe-rior labrum injury, 16SLAP, 7 posterior labrum injury, 2 superi-or anterior labrum injury. The glenohumeral ligaments injuries: 3 IGHL, 2 MGHL, and 1 patient had both MGHL and IGHL injury. Seventy patients underwent arthroscopy. Statistical anal-ysis of MR ARTHROGRAPHY with ABER in evaluation of labrum and ligamentous injuries with reference to arthroscope as a gold standard yielded 97.4% sensitivity, 93.5% specificity, 95% PPV, 96.6% NPV and 95.7% diagnostic accuracy. Conclusion: MR ARTHROGRAPHY with additional ABER demonstrated high sensitivity and excellent diagnostic accuracy for detection and description of the extent of glenoid labrum and glenohumeral ligaments injuries. Anatomical variants, especially at the superior quadrant, still may result in false positive tears. Adding ABER to MR ARTHROGRAPHY is challenging to the radiology team regarding patient positioning, imaging planning, anatomy interpretation, and lengthened scan time, however it is a good supportive imaging view especially in the evaluation of the anteroinferior quadrants and the IGHL injuries.