Glenohumeral instability

Symptomatic subluxation/dislocation of glenohumeral joint
Most are anteroinferior instability (95%); also may be posterior, inferior, superior or multidirectional
Fractures of glenoid and humeral head, tears of labroligamentous complex are seen
MR arthrography - sensitivity 92%, specificity 92%; aAbducted externally rotated - ABER position is preferred

Classification:
TUBS: Traumatic Unidirectional Bankart Surgery - trauma with anteroinferior instability associated with fibrous or osseous Bankart lesion requiring surgical repair
AMBRI: Atraumatic Multidirectional Bilateral Rehabilitation Inferior capsular shift - multidirectional instability involving both glenohumeral joints due to atraumatic ligamentous and capsular laxity and treated by rehabilitation and inferior capsular shift

References:
Ostlere S. Imaging the shoulder.Imaging 15:162-173 (2003)