The main symptoms of acromioclavicular impingement are pain, decreased strength, and limited shoulder motion, which may occur after trauma, but the pain often progresses insidiously over weeks or months, usually with a history of pain during upper arm abduction, touch, supination, and throwing movements. Patients may need to perform repeated upper arm abduction and supination during work or recreational activities, such as painting or playing tennis, and prolonged upper arm abduction and supination can exacerbate symptoms. The pain usually radiates in the anterolateral aspect of the shoulder joint toward the deltoid stop. When shoulder pain appears, patients often complain that the affected shoulder joint is compressed at night or that the pain is aggravated by abduction and supination of the upper arm while sleeping, and the shoulder joint is most pronounced when abducted to 60°-120°, and pain is absent beyond 120°. Because of the pain and concurrent rotator cuff tears, the shoulder joint strength decreases and the activity is affected. The shoulder joint abduction restriction is the most obvious and can be combined with the decrease in internal rotation activity, but the shoulder joint external rotation activity is generally normal, which is an important basis for differentiation from frozen shoulder. The cause of the disease is mild contact between the rotator cuff and the rostral shoulder arch when abduction is excessive. Any factors affecting the ability of the rotator cuff to fix the humeral head or damage to the rostral shoulder arch can lead to rotator cuff impingement, including calcium deposits, bursal thickening, and other unfused acromion tuberosities; type II and III acromion rostral shoulder ligament hypertrophy and calcification, and non-acromial bony redundancy of the acromioclavicular joint affecting the outlet size can lead to rotator cuff impingement; other functional Overload, intrinsic tendon disease, and local tendon injury thickening can also lead to rotator cuff impingement.