A 29-year-old strong guy, usually very fond of sports, especially playing basketball and badminton. A traumatic injury during basketball led to a dislocation of the shoulder joint, which was reset by a doctor in the orthopedic emergency department of a hospital. He thought he was fine, but later on, several dislocations occurred during sports. He was examined by a sports medicine specialist and underwent surgery. It is said that five anchor nails were used to repair the joint capsule during the surgery. Two years after the surgery, he tried to do a vigorous snapping motion while playing badminton, and the dislocation occurred again. Further examination at the hospital concluded that there was a large bony defect in the shoulder joint, and subsequently underwent a rostral transfer surgery, which is said to be internationally popular. After the second surgery, the shoulder joint never dislocated again, but I still had a feeling of instability in the shoulder joint when I swung my arm in the backward direction, and I no longer dared to play basketball or badminton. What is this? Why is it so difficult to treat shoulder dislocation? This requires a detailed understanding of the characteristics of shoulder dislocations, especially anterior shoulder dislocations. Anterior shoulder dislocation The shoulder joint is the most mobile joint in the body and is also the joint most prone to dislocation. The shoulder joint in the narrow sense refers to the glenohumeral joint, which consists of the scapular glenoid, the humeral head and the joint capsule ligament that connects the two. Under normal circumstances, the humeral head is always in alignment with the scapular glenoid due to the restriction of the capsular ligament, despite the large range of motion of the shoulder joint (Figure 1). If for any reason the humeral head and scapular glenoid lose their alignment, it is called a dislocation of the shoulder joint. The incidence of shoulder dislocation accounts for more than 50% of all joints in the body and can occur in all directions, with anterior dislocation of the shoulder joint having the highest incidence. The above guy is an anterior dislocation of the shoulder joint. At the moment of anterior dislocation of the shoulder joint, the humeral head breaks through the ligaments of the joint capsule and slides to the anterior or anterior-inferior side of the scapular pelvis. This dislocation causes three common structural injuries: first, the humeral head breaks forward causing a tear in the anterior capsular ligament, which is often associated with the glenoid labrum of the scapular glenoid (Bankart injury); second, the humeral head slides forward and impacts the anterior inferior border of the scapular glenoid, causing a fracture or bone defect on the anterior inferior border of the scapular glenoid; and second, when the humeral head slides forward the anterior border of the scapular glenoid reverses against the posterior border of the humeral head, causing a fracture or bone defect on the posterior border of the scapular glenoid. In addition, when the humeral head slides down, the anterior edge of the scapular glenoid impinges on the posterior aspect of the humeral head, causing a bone defect in the posterior portion of the humeral head (Hill-Sach injury) (Figure 2).