Multidirectional instability: surgical decision making.

Although previous authors have described multidirectional instability of the shoulder, it was not until 1980 that Neer and associates solidified the current understanding and treatment of inferior and multidirectional instability. They emphasized the importance of differentiating this condition from the more common unidirectional instabilities and introduced the concept of an inferior capsular shift to globally tension the capsule anteriorly, inferiorly, and posteriorly, while thickening and reinforcing it on the side of greatest instability (i.e., anterior or posterior). Since the time of this initial description, the diagnosis and treatment of multidirectional instability has been fraught with difficulty and confusion. More recently, the advent of shoulder arthroscopy has blazed the trail for minimally invasive techniques to correct multidirectional instability, including arthroscopic thermal capsulorrhaphy and suture plication. However, despite strong opinions regarding these surgical techniques, when comparing open approaches to arthroscopic techniques for the treatment of multidirectional instability, long-term outcomes of arthroscopic techniques have yet to replicate those of open surgery.