The rotator cuff is composed of the tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles, which are attached to the superior humeral tuberosity in a cuff-like fashion, with the tendonous portions intertwined at the termination point to form a tendon cap-like structure. Rotator cuff injuries are common in young adults and older adults and are caused by traumatic injury or degeneration of the rotator cuff tendon based on anatomic structural abnormalities resulting in injury rupture. Rotator cuff injuries are classified into traumatic rotator cuff injuries and secondary degenerative rotator cuff injuries depending on the cause of the rotator cuff injury. Patients with traumatic rotator cuff injuries often have a history of significant shoulder trauma, such as hand bracing during a fall, lifting heavy objects, sprains, and other causes of acute violence resulting in rotator cuff tears. Secondary degenerative rotator cuff injuries are commonly seen in older adults over 60 years of age, and there is mostly an underlying factor of subacromial impingement. Depending on the degree of injury, there are two types of injuries: partial and complete. The most important clinical manifestations of rotator cuff injury are: ① pain in the neck and shoulder; ② weakness of the shoulder joint; ③ limited active range of motion of the shoulder joint. The most typical pain is nocturnal pain in the neck and shoulder and “over-the-top” activity (when the affected limb is raised above the top of the head, referred to as “over-the-top” activity), sometimes accompanied by radiating pain to the neck and upper limbs, and the pain is aggravated by lying on the affected side, seriously affecting sleep. The patient is in great pain. Shoulder joint weakness can be manifested as weakness in abduction, weakness in supination, or weakness in posterior extension; active movement of the shoulder joint is limited due to pain and weakness, but passive range of motion is usually not significantly limited. The diagnosis of rotator cuff injury mainly relies on medical history, formal physical examination, X-ray, ultrasound or magnetic resonance, and arthrography to provide the basis for diagnosis; arthroscopy is the most reliable method of confirming the diagnosis, which is invasive and is generally used when simultaneous surgical treatment is required, and diagnosis and treatment are carried out simultaneously.