[Useful imaging data before intervention for an unstable shoulder].

Recurrent instability of the shoulder may sometimes be a difficult diagnostic challenge. Bernageau's standard X-rays set, which includes 3 antero-posterior X-rays with medial rotation and 2 glenoid views, is able to confirm the existence of anterior instability events. However, it gives no information on the glenoid labrum and the glenohumeral ligaments. As surgical techniques are more sophisticated, more precise imaging techniques are needed in order to adapt the surgical technique to the anatomical lesions. Although CT arthrography is today the best imaging technique to choose a surgical technique, it will probably be replaced by MR arthrography in the near future. Pros and cons of each imaging techniques are described, together with their implications for the choice of treatment.