An arthroscope is an endoscope used to diagnose and treat joint disorders. It consists of a central image acquisition rod system, a peripheral optical fiber that introduces a light source, and an outer metal protective sheath. By creating a small incision in the skin of about 0.6cmD1.2cm and inserting a thin tube with a lens at the end into the joint, the internal structure of the joint is displayed on the monitor, allowing direct observation of the intra-articular morphology and lesions and treatment of intra-articular diseases with special instruments, thus avoiding many joint incisions. This device has been used since 1970 and has been referred to as one of the three most important advances in the field of orthopedics in the 20th century, along with internal fracture fixation and artificial joint replacement. Arthroscopy is not only used for the diagnosis of disease, but has been widely used for the treatment of joint disease. Arthroscopic surgery was mainly applied to the knee joint at the beginning, but later it was applied to the hip joint, shoulder joint, ankle joint, elbow joint and so on. Advantages of arthroscopic shoulder surgery 1. Arthroscopy allows you to see almost all parts of the joint, which is more comprehensive than cutting open the joint. 2. Since the image is magnified, it can be seen more accurately. 3.Small incision, less trauma, less scarring, faster recovery, less complications, and in some cases, after anesthesia, you can move around. 4. It is convenient and accurate to confirm the diagnosis of difficult diseases of the joints, and the lesions in the joints can be observed and examined in a near physiological environment, which is called “putting eyes and fingers into the joints”. Contraindications: 1. It is generally believed that the main contraindication is joint stiffness, because it will affect the operation of arthroscopy. 2. Systemic or local infectious diseases. Severe hypertension, heart disease, diabetes mellitus, or other serious diseases where the patient cannot tolerate anesthesia and surgery. Complications: infection, thromboembolic disease, intraoperative instrument breakage, complex regional pain syndrome, injury to ligaments or even fracture or nerve injury. Shoulder arthroscopy can be used for the diagnosis and partial surgery of most shoulder disorders. It can be used to visualize and manage lesions within the shoulder joint, including the subacromial region, under direct vision, to make a definitive diagnosis and guide the choice of surgical approach, while avoiding the trauma associated with blind incisional exploration. Shoulder arthroscopy usually provides important information that cannot be found on plain films, imaging, CT or MRI. The main treatment areas: shoulder instability, periarthritis, rotator cuff tears, acromion impingement syndrome, calcific supraspinatus tendonitis, exfoliative osteochondritis, and synovial chondromatosis.