Serious impingement syndromes of the shoulder unresponsive to conservative measures can be relieved by means of the approved open anterior acromioplasty. However, the rise of shoulder arthroscopy allowed the same procedure to be performed arthroscopically. Based on an accurate indication the outcome of arthroscopic subacromial decompression may be considered as equally successful as that obtained by the open procedure. The advantages of the arthroscopic approach are: a significantly less gross destruction of the deltoid and--as a result--a reduced rehabilitation period a smaller incision and the possibility of an arthroscopic inspection of the joint prior to decompression For the repair of complete tears of the rotator cuff the arthroscopic procedure will provide less satisfactory long-term results. For those cases the open reconstruction will remain the treatment of choice.