Assessment of bone loss in anterior shoulder instability

Anterior shoulder dislocations commonly result in predictable patterns of osseous injury on both the glenoid and humeral side. The presence of bone loss contributes to the risk of recurrent dislocations, as well as the success of surgical intervention. For example, in patients with glenoid lesions comprising >25% of the glenoid surface or Hill-Sachs lesions that “engage” the glenoid rim, the recurrence rate has been reported to be as high as 67% after soft tissue Bankart repair. The range of injury severity and anatomic variations in soft tissue and bony injury patterns associated with anterior shoulder instability makes identification and quantification of these lesions critical prior to surgical intervention. Historically, bony lesions on the glenoid and humeral side were considered independently. More recently, the interaction between the two and their summative effects on recurrence and operative outcomes has become better understood. The purpose of this review is to provide an overview of the historical methods of identifying bony lesions, as well as an update on current concepts in quantifying bone loss in anterior shoulder instability.