Shoulder impingement syndrome (SIS) refers to a combination of shoulder symptoms, examination findings, and radiologic signs attributable to the compression of structures around the glenohumeral joint that occur with shoulder elevation. Such compression causes persistent pain and dysfunction. Shoulder pain is a common presenting complaint in primary care clinics, and SIS is likely the most common cause of shoulder pain in this setting [1,2].
Much has changed in our understanding of shoulder function and dysfunction since Neer's original classification of these disorders decades ago . The diagnosis of SIS implies a spectrum of clinical findings, not injury to a specific structure.
The pathophysiology, diagnosis, and management of SIS will be reviewed here. The approach to patients with shoulder pain, the shoulder examination, and conditions that may stem from SIS are discussed elsewhere. (See "Evaluation of the patient with shoulder complaints" and "Physical examination of the shoulder" and "Rotator cuff tendinopathy" and "Presentation and diagnosis of rotator cuff tears".)
EPIDEMIOLOGY AND RISK FACTORS
Shoulder pain is highly prevalent within the general population, second only to lower back pain. Studies suggest that shoulder impingement syndrome (SIS) is the most common cause of shoulder pain [4-7]. However, epidemiologic calculations can vary depending upon how SIS is defined.
Risk factors — Repetitive activity at or above the shoulder during work or sports represents the main risk factor for SIS. As with many shoulder disorders, increasing age also predisposes to SIS [7,8]. SIS is common among athletes who participate in overhead sports [9-14]. These sports may include swimming, throwing, tennis, weightlifting, golf, volleyball, and gymnastics . Overhead work activities that can increase risk for developing SIS include painting, stocking shelves, and mechanical repair [6,16].