Subacromial decompression was performed arthroscopically on 65 patients who were evaluated two to five years after the procedure. None had full thickness rotator cuff tears. Patients with partial thickness cuff tears were included in this study in order to allow comparison of arthroscopic acromioplasty with open acromioplasty for stage II impingement. On the UCLA shoulder rating scale, 89% of the cases in this study achieved a satisfactory result. These results compare favourably with those reported following open acromioplasty. The arthroscopic procedure is technically demanding. When properly performed in patients with appropriate indications, hospitalisation is brief, return to activities is rapid, there is little risk of deltoid muscle complications, and the results are lasting.