The Rotator Interval of the Shoulder: Anatomy, Biomechanics, and Repair Techniques

Abstract

The role of the rotator interval (RI) in maintaining stability of the shoulder joint remains controversial. Defined as the triangular-shaped space between the supraspinatus and subscapularis tendons, the RI is an area of complex anatomy that contains the superior and middle glenohumeral ligaments, the coracohumeral ligament, the long head of the biceps, and a thin layer of capsule. The RI has frequently been touted as an area that is important in preserving stability of the shoulder because an incompetent RI has been implicated in various conditions of shoulder instability. Biomechanical research suggests that surgical repair of the RI improves the overall stability of the shoulder joint predominantly in the anterior and potentially inferior directions. With the advent of arthroscopic techniques for the treatment of shoulder instability, the differences between an arthroscopic and open RI closure have been delineated. The purposes of this review were to investigate the anatomy and biomechanical function of the RI in shoulder instability, to review the techniques of surgical repair, and to describe the effect of RI closure on glenohumeral kinematics. Additionally, some of the controversies regarding the indications for RI closure will be discussed.