OBJECTIVE Coracoacromial ligament release to widen the subacromial space, resection of the anterior undersurface of the acromion and, if needed, caudal exophytes at the acromioclavicular joint. METHODS All types of outlet impingement after 3 months of conservative treatment. METHODS Impingement syndrome with instability/muscular imbalance, massive rotator cuff tear, unstable os acromionale, posterior-superior impingement, joint infection, freezing phase of a secondary frozen shoulder. METHODS Lateral decubitus position with traction device for the arm. Diagnostic arthroscopy of the glenohumeral joint via standard portals. With arthroscope moved to the subacromial space, bursectomy, electrosurgical release of coracoacromial ligament, resection of acromial hook through standard posterior portal. METHODS Physiotherapy or self-exercises on postoperative day 1, pain-adapted analgesia to avoid shoulder stiffness. RESULTS Several studies present positive long-term results compared to conservative treatment (and open acromioplasty) for partial rotator cuff tears and for elderly patients. With a 20-year follow-up, successful results have been achieved for all patients with isolated impingement syndrome.