I often encounter patients with shoulder pain, some of whom have been going around for a long time in other hospitals. Most of the doctors and patients’ knowledge about shoulder pain is still limited to frozen shoulder and so on. It is true that frozen shoulder is a high percentage of shoulder pain patients, but in fact, the higher percentage of attacks is a condition called subacromial impingement syndrome. Let’s talk about the difference between frozen shoulder and subacromial impingement syndrome. The former is characterized by inflammatory pain and most of the joint movement is restricted. The latter is characterized by painful movement and relatively high joint mobility, but is more painful when performing a certain movement or being in a certain position. The former tends to occur in patients around 50 years of age, with a female predominance. The latter occurs in all age groups, but is more common in those over 50 years of age. It is caused by the aging of the tendons, ligaments and bones of the shoulder, which cause pain due to mutual impingement. There are also young people who have subacromial impingement syndrome in their 30’s. This is because these patients have a poorly developed shoulder structure, which makes them more susceptible to the onset of this impingement. Or the impingement may be caused by other causes of shoulder instability. Another clinical condition that is also very common is when both of these conditions are accompanied by cervical spondylosis or thoracic outlet syndrome. It manifests as pain in both the shoulder and neck, sometimes the pain in the neck is not obvious, or there is a numbness in the arm, etc. At this time, if the doctor is not experienced enough, it will happen that the treatment is only for one kind of disease, and that will not receive good results. In our hospital, because we are a specialized hospital for rheumatoid diseases, many synovitis and tendonitis of the shoulder joint are also very common. There are also some rare causes of shoulder pain, such as shoulder infections and local tumors that compress the nerves causing shoulder pain. So how do we deal with the intrusion of shoulder pain? The first thing is definitely a clear diagnosis. A clear diagnosis must contain information about three aspects, the location, nature and extent of the disease. If it is an inflammatory disease, within two months, medication (including oral, topical and injection) and physiotherapy can be administered. Over three months, surgery is possible if possible. Why? Previous studies have shown that cartilage and ligaments begin to show destruction after three months in an inflammatory environment. So three months is the limit. Some may ask, what about between two and three months? That depends on the situation. These are the principles of treatment for inflammatory disease, but if the disease is caused by structural changes, a different principle is needed. In the shoulder, subacromial impingement syndrome is a disease caused by structural changes, and the inflammation it produces is often the result, not the cause of the disease. Therefore, removing the structural cause of impingement and rebuilding a good biomechanical structure is the effective solution to this problem. Therefore, surgery is the preferred direct and effective method, but in some milder patients who have not had the disease for a long time, conservative treatment methods such as medication and physical therapy can be used first. When people hear about surgery, there is always resistance in their hearts. Who wants surgery when they have nothing to do? But to deal with this kind of structural problems of the disease, surgery is like a dangerous house renovation, there is quite targeted. It is a good thing that our industry sages have invented arthroscopy, which is commonly known as “minimally invasive” surgery. This allows the patient to suffer very little trauma and recover very quickly after surgery, giving us confidence that the disease can be cured.