Research on frozen shoulder has identified different pathological changes from different perspectives and has proposed numerous etiological theories. “Frozen shoulder” is a syndrome of shoulder pain and motor dysfunction, and is not a single cause of disease. The broad definition of frozen shoulder includes subacromial bursitis, supraspinatus tendonitis, rotator cuff tears, biceps longus tenosynovitis, rostral synovitis, frozen shoulder, acromioclavicular joint lesions, and many other disorders. The term “frozen shoulder” in the narrow sense is used as a synonym for “frozen shoulder” or “fifty shoulder” in China. Common clinical manifestations: The disease is divided into three phases: Acute phase: also known as the freezing phase. The onset of the disease is acute, with severe pain, muscle spasms and limited joint movement. The pain increases at night, making it difficult to sleep. The pressure pain is widespread and there is no abnormality on x-ray examination. Chronic phase: also known as the freezing phase. The pain is relatively relieved at this time. The joint function is limited by the muscle spasm in the acute phase to joint contracture dysfunction. The soft tissues around the joint are “frozen”, and the shoulder crest, large nodules with sparse bone and cystic changes can occasionally be observed on X-ray. Arthroscopic examination: adhesions in the joint cavity, reduction of joint volume, fibrous strips and floating debris in the cavity. Functional recovery period: Inflammation is gradually absorbed, blood supply is normalized, synovial fluid secretion is gradually restored, adhesions are absorbed, joint volume is gradually restored to normal, and most patients can restore normal or near normal shoulder function. Muscle atrophy requires a longer period of exercise to return to normal. Treatment options and principles: Non-surgical treatment: Acute antispasmodic and analgesic. Braking, oral non-steroidal drugs and local injections can be used. Freezing phase treatment principle: do appropriate functional exercises under pain relief conditions to prevent the joint contracture from worsening. Manual release surgery: It is indicated for patients with shoulder contracture who are pain-free or whose pain has been largely relieved. It is performed under general anesthesia: posterior extension release in the sagittal plane, adduction release in the coronal plane, and finally axial release in internal and external rotation. Surgical treatment: The indications are freezing stage patients with severe joint contracture, and if non-surgical treatment is ineffective, surgical peeling of adhesions can be used.