[Shoulder impingement].

The impingement syndrome is a common disorder of the shoulder girdle. The causes for this syndrome may be anatomic changes in the coracoacromial arch, also within the ultrastructural regions, on the one hand, or changes in the biomechanics which have developed for various reasons, on the other. Diagnosis is based on roentgenograms using the appropriate technique. In large-scale-studies, sonography has proved to be an extremely sensitive screening method for differential diagnosis of rupture of the rotator cuff. Magnetic resonance imaging might gain in value in the diagnosis of impingement as regards differential diagnosis of rupture of the rotator cuff because this technique--when employed appropriately--allows exact viewing of the soft tissue and the anterior part of the acromion. In the majority of cases conservative treatment is the method of choice. Methods of treatment are sonography, galvanization, and application of heat. Physiotherapy should not be initiated until pain relief has been achieved by other measures. Infiltration therapy is of considerable value in the management of pain due to impingement. Application of cortisone into the subacromial space must also be considered critically. As regards conservative therapy, only few evidence-based publications provide information on the effectiveness of different treatment regimens. Surgical therapy is only indicated in cases of pain resistant to the conservative therapy for a certain period. Furthermore, only an outlet impingement can be treated successfully by surgical decompression. The surgeon decides on the surgical method--open surgery or arthroscopy. Of course, arthroscopic methods are less invasive; however, up to now the superiority of one of the surgical methods over the other could not yet be proven by mid-term clinical results. Other surgical methods such as wedge osteotomy in the region of the spina scapulae are still in the experimental stage. By surgical and conservatives methods, good and even excellent results can be achieved in about 80% of the cases. The question remains as to why 20% of the patients show unsatisfactory results. One explanation might be that factors such as pathologic changes of the muscular balance and an altered microstructure of the tendons of the rotator cuff are rarely taken into consideration and Neer's concept of decompression is overestimated. Further research will be required in the field of biomechanics but clinical research on treatment concepts should also be undertaken to develop more differentiated strategies of treatment.