Most traumatic anterior shoulder instability is associated with soft tissue lesions, and the typical finding is a Bankart lesion with or without capsular laxity. Numerous biomechanical studies have supported this observation. Soft tissue repair, using either open or arthroscopic techniques, has been shown to have a very high rate of success. In rare cases, significant bony lesions have been associated with recurrence of instability, although the incidence and recognition of such lesions remain variably reported.
Rowe suggested that a 30% loss of the anterior glenoid was still amenable to a soft tissue Bankart repair. However, this was an observation based on qualitative visual inspection and anecdotal experience. Burkhart have observed that substantial bony loss of the anterior glenoid is associated with a very high recurrence rate after arthroscopic repair of instability. They developed a method of arthroscopic inspection to determine what constituted clinically relevant bone loss. Few other studies have drawn attention to the biomechanical relevance of stability afforded by glenoid depth and width. Recently, Gerber and Nyffeler have provided a method of quantitative assessment of glenoid bone loss and determined its importance to stability of the glenohumeral joint.