Impingement syndrome

Impingement syndrome is a special category of supraspinatus tendinitis caused by irritation of the subacromial bursa or rotator cuff tendon from mechanical impingement between the humeral head and the coracoacromial arch, which includes the acromion, coracoacromial ligament, and the coracoid process. Chronic overhead activity may contribute to narrowing of this space, which can lead to recurrent microtrauma and chronic local inflammation of rotator cuff tendons. Pain on the Hawkins test that resolves with injection of lidocaine into the subacromial space helps establish the diagnosis. Initial treatment is similar to rotator cuff tendinitis; however, persistence of symptoms after 3 months, which occurs in 10% to 25% of patients, may warrant an orthopedic referral.