The term “frozen shoulder” is a widely spread disease among the general public, and all pain and limited movement in the shoulder joint area are attributed to “frozen shoulder”. However, with the development of shoulder medicine in China, the term “frozen shoulder” is too general and confusing in the process of diagnosis and treatment, and cannot meet the needs of specialized treatment, so this term has been abandoned in the specialty of shoulder surgery. The shoulder joint is a very complex joint and is the most mobile and flexible joint in the body. The most common conditions that cause shoulder pain and limited motion include rotator cuff injury, subacromial impingement syndrome, habitual shoulder dislocation, and frozen shoulder, and most shoulder disorders can now be treated minimally invasively under arthroscopy. The rotator cuff, an important component of the shoulder joint, consists of the subscapularis tendon, supraspinatus tendon, infraspinatus tendon, and lesser trochanter, and wraps around the humeral head from the anterior, superior, and posterior aspects of the shoulder joint to strengthen the stability of the shoulder joint and maintain shoulder motion. Statistically, the highest incidence of shoulder disorders is rotator cuff injuries, which account for 30-40% of shoulder disorders. Rotator cuff injury is a very common degenerative disease of the shoulder joint, and its occurrence is positively correlated with age, especially in people over 50 years of age. Rotator cuff injury often causes shoulder pain and is accompanied by shoulder abduction weakness. Rotator cuff injuries are common in athletes, people who lift heavy objects, and people who have sustained traumatic injuries. Typical symptoms are pain in the neck and shoulder at night and pain in the arm when lifting; sometimes they do not dare to sleep on the affected side and even wake up with pain; the shoulder joint can be weak when abducting, lifting or extending, and sometimes even personal hygiene is difficult, which seriously affects the patient’s life. Due to the lack of awareness in most hospitals, rotator cuff injuries are often misdiagnosed or missed, which delays the treatment of patients and even causes irreparable rotator cuff injuries due to long time missed diagnosis. At present, the technology of minimally invasive treatment of rotator cuff injury under arthroscopy is quite mature, and only 3-4 0.5 cm sized “holes” are needed to relieve the patient’s long-term pain. Shoulder impingement The shoulder impingement is a condition in which the acromion and subacromial bursa tissues impact and crush against the rotator cuff tissue during shoulder abduction and supination, resulting in shoulder pain and supination dysfunction. In general, impingement and rotator cuff lesions occur more often in older individuals and throwing athletes. Since repeated impingement tends to damage the rotator cuff, rupture of the rotator cuff tissue can easily occur. The patient’s shoulder pain gradually worsens, and the symptoms increase when throwing or lifting the arm. The pain often radiates to the proximal lateral and mid-portion of the arm. If treatment is delayed, the patient may experience severe muscle atrophy and sleepless nights; if left to develop, the later stages may lead to rupture of important tendons in the shoulder joint, seriously affecting the patient’s function and life. Habitual shoulder dislocation As the quality of life in China continues to improve, participation in physical exercise has become an integral part of daily life. Shoulder dislocation is a common injury, mostly in young people, and the incidence of recurrent dislocation is high. Habitual shoulder dislocation is common after trauma or contact sports such as basketball, soccer, and wrestling. The shoulder joint is one of the more unique joints in the human body and is the most mobile of all the joints in the body. Unlike other joints, the stability of the shoulder joint relies heavily on the balance of tension in the soft tissues around the shoulder joint, including muscles and ligaments. Recurrent shoulder dislocation can seriously affect the function of the shoulder joint, as the dislocation causes tears in the shoulder capsule and ligaments, and the stability of the shoulder joint is damaged. This not only prevents sports activities, but also affects daily life (any position of abduction and external rotation – such as sitting back in front of a car and holding something in the back – can trigger dislocation). If allowed to develop, it will cause irreversible damage to the articular cartilage and joint bone, resulting in lifelong pain and regret. From clinical experience, conservative treatment for recurrent shoulder dislocation is less effective, especially in younger patients, so surgery is usually needed to reconstruct the torn joint capsule and ligament tissue to repair the stable structure of the shoulder joint. In recent years, with the continuous development of arthroscopic techniques and instruments, very satisfactory treatment results can be obtained through arthroscopic techniques for habitual shoulder dislocations. The arthroscopic shoulder surgery has the advantages of less trauma, less pain and faster functional recovery. The surgery that used to require 8-10 cm incision can be solved by arthroscopic surgery with only 2-3 small incisions of 0.5 cm. Frozen shoulder The real meaning of “frozen shoulder” is called frozen shoulder in medical terms, which is commonly known as “fifty shoulder”. Frozen shoulder is a self-limiting disease of unknown etiology that occurs between the ages of 40 and 50. The cause is not well understood, but some studies suggest that it is associated with autoimmune diseases and infections, and a history of diabetes is also a risk factor. The pathology is characterized by severe adhesions of the joint capsule within the shoulder joint. The symptoms are progressive limitation of shoulder motion without cause, especially limitation of external rotation, and pain in the shoulder joint, which can affect sleep in severe cases. The pain and limitation of motion peak 3-6 months after the onset of the disease, after which the symptoms gradually resolve. Sometimes the onset of symptoms in one shoulder joint may be followed by an attack in the other shoulder joint some time later. The diagnosis of frozen shoulder is a diagnosis of exclusion, which means that all diseases that may cause shoulder pain and limited movement, such as rotator cuff injury, post-traumatic adhesions, and osteoarthritis of the shoulder joint, need to be excluded before a conclusion can be made. Due to its self-limiting course, the treatment of most frozen shoulders does not require surgery, but strict and active functional exercises must be performed under the guidance of a physician. The goal is to maintain a certain degree of shoulder mobility as much as possible during the period of restricted shoulder movement, so that normal shoulder movement can be maintained even after the joint adhesions recover on their own. For a small number of patients who cannot relieve themselves, surgical treatment is required. In recent years, with the development of arthroscopic surgery, we can perform arthroscopic release of the joint capsule and supplement it with pushing and releasing under anesthesia, which can obtain satisfactory results. Functional exercises for the treatment of frozen shoulder include 4 simple movements: anterior flexion supination, external rotation, internal retraction and internal rotation.