Purpose of this study is to examine the role of MRI arthrography in chronic cases of shoulder instability. Shoulder arthroscopy was elected as standard record of diagnosis.

Patients & Method: We evaluated 155 shoulder arthroscopies in 153 cases of recurrent shoulder instability from Sept 99 to Feb 03. Each patient suffered at least 2 true dislocations. Pre-op, we performed MRI scan in 82 of them while, 15 other cases were evaluated more invasively with MRI arthrography, with anterior portal infusion technique. Results were analyzed blindly from 2 radiologists with particular experience in MRI musculoskeletal cases and were compared to arthroscopic findings.

Results: Bankart lesion was diagnosed in all cases with MRI arthrography (sensitivity 100%), SLAP lesion had sensitivity 50% and specificity 100% while, rotator cuff pathology was diagnosed in 6 out of 7 cases. There were also 4 false positive cases in rotator cuff pathology. Sensitivity for superior and inferior gleno-humeral ligament was 100% and 94% respectively, without any true negative findings in both of them. Sensitivity and specificity for middle glenohumeral ligament was 89% and 60% respectively. In cases where we recognized loose anterior capsule pathology during arthroscopy, the radiologists were not able to detect these lesions from a functional aspect. Despite the fact, that all Hill Sachs lesions were identified through MRI arthrography it was also possible to be detected functionally.

Conclusions; MRI arthrography is a reliable tool in recurrent shoulder instability while is an invasive method because of the infusion material. Anterior glenohumeral instability is not always a Bankart lesion but gleno-humeral ligaments pathology too that, can easily be detected during arthroscopy which may be the therapeutic solution at the same time.