Shoulder arthroscopy has undergone dramatic advancements in the past few years. New biomechanical concepts, such as the functional rotator cuff tear, have led to new treatments, such as partial repair of massive rotator cuff tears. Techniques have evolved to repair rotator cuff tears and Bankart lesions arthroscopically. The shoulder with multidirectional instability will likely soon be treatable arthroscopically. Arthroscopic approaches to adhesive capsulitis have been applied successfully. The concepts of instability impingement overlap and internal impingement have allowed better understanding of dysfunction in the shoulders of throwing athletes.