Published Evidence Relevant to the Diagnosis of Impingement Syndrome of the Shoulder

Background: Acromioplasty for impingement syndrome of the shoulder is one of the most common orthopaedic surgical procedures. The rate with which this procedure is performed has increased dramatically. This investigation sought high levels of evidence in the published literature related to five hypotheses pertinent to the concept of the impingement syndrome and the rationale supporting acromioplasty in its treatment. Methods: We conducted a systematic review of articles relevant to the following hypotheses: (1) clinical signs and tests can reliably differentiate the so-called impingement syndrome from other conditions, (2) clinically common forms of rotator cuff abnormality are caused by contact with the coracoacromial arch, (3) contact between the coracoacromial arch and the rotator cuff does not occur in normal shoulders, (4) spurs seen on the anterior aspect of the acromion extend beyond the coracoacromial ligament and encroach on the underlying rotator cuff, and (5) successful treatment of the impingement syndrome requires surgical alteration of the acromion and/or coracoacromial arch. Three of the authors independently reviewed each article and determined the type of study, the level of evidence, and whether it supported the concept of the impingement syndrome. Articles with level-III or IV evidence were excluded from the final analysis. Results: These hypotheses were not supported by high levels of evidence. Conclusions: The concept of impingement syndrome was originally introduced to cover the full range of rotator cuff disorders, as it was recognized that rotator cuff tendinosis, partial tears, and complete tears could not be reliably differentiated by clinical signs alone: The current availability of sonography, magnetic resonance imaging, and arthroscopy now enable these conditions to be accurately differentiated. Nonoperative and operative treatments are currently being used for the different rotator cuff abnormalities. Future clinical investigations can now focus on the indications for and the outcome of treatments for the specific rotator cuff diagnoses. It may be time to replace the nonspecific diagnosis of so-called impingement syndrome by using modern methods to differentiate tendinosis, partial tears, and complete tears of the rotator cuff.