[Multidirectional shoulder instability. Nonoperative and operative treatment strategies]

Multidirectional shoulder instability (MDI) is characterized by symptomatic instability in at least two directions, often with a global hyperlaxity. The etiology is mostly atraumatic, with an acquired or congenital enlarged capsular volume or redundancy. Muscular imbalances and pathologic patterns of muscle recruitment and motion are also common findings. Traumatic onset of MDI is rare, although capsulolabral lesions can be found during surgery. Therapy aims at a normalization of muscle balance/weakness and motion patterns. If conservative treatment fails, arthroscopic capsular plication techniques, in combination with repair of labral and interval lesions, can accomplish results similar to those of classic open techniques but with reduced morbidity and invasiveness.