Acromioclavicular impingement is also known as subacromial impingement. As the name suggests, it is a disease in which the most prominent point on the humerus below the shoulder joint is elevated to a certain position, and the most prominent point on the humerus, which is called the greater tuberosity of the humerus in medical terms, impacts with the top of the scapula above, which is called the front and bottom of the acromion, thus causing pain to the patient. However, due to the neglect of shoulder diseases in China, it has been classified as frozen shoulder until recent years, with the continuous development of shoulder arthroscopy technology, it has received more and more attention from the medical community at home and abroad. The clinical manifestations of the disease are mainly shoulder pain, which is an insidious pain, especially at night, making it difficult for the patient to sleep and radiating around the deltoid muscle. This is the primary reason why many patients come to the doctor. Secondly, the patient may say that the pain occurs when my arm is raised to a certain angle, usually from about 60° to 120°. Or the passive movement may be basically normal, but the active movement is not. Age-wise, these patients are usually over 40 years old. Combining these points then you may have the possibility of acromioclavicular impingement. Then you may need to go to the hospital to see a specialist joint surgeon for a full physical examination of the shoulder joint and, if there is a problem, an MRI of the shoulder joint to confirm the diagnosis. Once the diagnosis of acromioclavicular impingement is confirmed, regular treatment will be required. This includes avoiding forceful shoulder lifting movements, taking anti-inflammatory and analgesic drugs, and localized physical therapy with heat. If the symptoms do not improve significantly, surgery is required. Although it is more difficult and expensive than traditional open surgery, it is less traumatic and the patient recovers quickly, which has incomparable advantages.