Frozen shoulder, also known as “frozen shoulder” or “fifty shoulder”, occurs in women around 50 years old and has a good prognosis. The main symptom is pain in the shoulder. The pain can be dull or knife-like, especially at night, or even waking up with pain, radiating to the forearm or hand, neck, or back, also aggravated by movement. The upper arm cannot be abducted, and internal and external rotation is significantly limited. Over time, the deltoid muscle becomes atrophied. Patients are unable to lift their arms, wash their faces or comb their hair. Generally, regardless of the cause, as long as the shoulder joint does not move or moves less, this disease will occur over time. There are four causes of frozen shoulder: idiopathic (or primary) frozen shoulder, diabetic frozen shoulder, post-traumatic shoulder stiffness, and post-surgical shoulder stiffness. The normal motion of the shoulder joint depends on the interscapular thoracic wall joint, the intra-articular capsule structures, and the extra-articular capsule structures. In addition to the joint capsule and ligaments and intra-articular scarring, extra-articular adhesions in areas such as the subacromial region are often present in trauma and post-surgical patients. This is often combined with joint dislocations, fractures, and injuries to the tissues surrounding the shoulder joint that are not treated properly. The lack of activity in the shoulder joint results in local metabolic disorders and peripheral blockage of blood and lymphatic return, resulting in degenerative changes around the joint such as the joint capsule, rotator cuff, biceps tendon and rostro-humeral ligament, with exudate leakage and cellular infiltration, followed by fibrosis, which consequently greatly limits the movement of the shoulder joint. Frozen shoulder is clinically divided into three phases, namely, acute phase, adhesive phase and remission phase. In terms of treatment, conservative treatment is the mainstay, and surgery is only considered for individual cases of severe joint adhesions. The main conservative treatments for frozen shoulder include NSAIDs, physical therapy, and intra-articular corticosteroid injections. If conservative treatment is not effective for 6 months and external rotation is in neutral position or worse with severe stiffness, surgical treatment should be considered, usually using shoulder arthroscopy for adhesion release. Postoperatively, rehabilitation functional training is continued until complete restoration of shoulder joint function. Acute phase: The pain around the shoulder joint is mainly indefinite, sometimes involving the upper arm and forearm. The limitation of joint movement is caused by the painful muscle spasm around the shoulder joint and the tightening of the surrounding soft tissues. Therefore, the focus of treatment during this period should be on relieving pain, supplemented by exercises to maintain shoulder mobility in all directions, both of which are complementary and indispensable. Adhesion phase: At this time, the patient’s pain symptoms are obviously relieved, but the shoulder joint adhesions and restricted joint movements are the main causes, especially the shoulder joint abduction and external rotation restrictions are the most obvious. Therefore, treatment during this period should focus on increasing the range of motion of the shoulder joint, supplemented by pain relief treatment. Remission phase: In this phase, the pain and limitation of joint movement are significantly better than before. Patients who actively cooperate with the treatment can fully recover the functional activities of the shoulder joint. On the other hand, some joint limitation may remain. However, most of them can gradually improve through daily life until they eventually recover.