[Static functional study with magnetic resonance of anterior shoulder instability]

We studied the glenohumeral joint, in its different components, with cine MRI. Ten asymptomatic volunteers and 6 patients with recurrent shoulder instability were examined with T2-weighted GE MR sequences on the axial plane with the subjects' arms rotated in different positions. The sections corresponding to the subcoracoid space and bicipital groove were recorded in closed-loop video format for cine display. Normal morphological glenoid labrum changes were demonstrated in different degrees of humerus rotation. The subscapularis tendon and the capsule were redundant and infolded toward the joint on internal rotation in 4/6 patients. We found capsular detachment in 2 patients, humeral head subluxation in 3 and subcoracoid impingement in 2 patients. Cine MRI permitted the accurate study of the changes in the glenoid labrum, capsule and subscapularis tendon in all patients and it also showed narrowed coracohumeral distance (< 11 mm) on internal rotation.