Shoulder joint dislocation is a common disease in the emergency department. Since the shoulder joint is flexible and unstable, the shoulder joint is the joint most prone to dislocation in the human body. Anterior shoulder dislocation is often associated with greater tuberosity fracture, and posterior dislocation of the shoulder is often associated with lesser tuberosity fracture. According to statistics, the incidence of anterior shoulder dislocation associated with greater tuberosity fracture is about 15%-30%. As with simple shoulder dislocation, shoulder dislocation with greater tuberosity fracture should be reduced immediately. Closed reduction of this kind of injury in the emergency room is still controversial, and there is a distinct possibility during the reduction process. Sex can lead to aggravated fracture displacement. Ehud Atoun et al. proposed that when the greater tuberosity fracture of the humerus is combined, the probability of iatrogenic humeral neck fractures due to manual shoulder dislocation reduction is significantly increased, shoulder dislocation combined with greater tuberosity fracture can be manually reduced under sedation in the emergency room. Mackenzie et al. found in their statistical cases that 188 conservatively treated shoulder dislocations combined with greater tuberosity fractures. Only two cases of iatrogenic fractures occurred among the patients who underwent a closed manual reduction in the emergency room. Reducing such fractures and dislocations in the emergency room was considered safe. Guo Junfei et al. proposed using the ratio of the size of the humerus's greater tuberosity to the humeral head’s size on the anterior view of the shoulder joint as an index to measure the risk of manual reduction. When the ratio is greater than 0.4, the risk of iatrogenic fractures increases significantly. However, this method is not accurate in clinical applications. Based on the above studies, it can be seen that manual reduction of shoulder dislocation with greater tuberosity fracture in the emergency room is still controversial, and there is still a lack of reliable methods.

Anterior dislocation of the shoulder joint with fracture of the greater tuberosity of the humerus is a common disease in the emergency department. There are still many controversies in its treatment. If an iatrogenic fracture occurs during manual reduction, it will increase the difficulty of treatment and affect the prognosis of patients. This paper analyzes the dislocation of the shoulder joint with humerus fracture based on the CT data of patients with greater tuberosity fractures. It was proposed that whether the CT crossed the intertuberous sulcus on the transverse plane was the criterion for whether the patients could perform the manual reduction.

The cases of shoulder dislocation treated in the emergency orthopedic department of Shanghai Changhai Hospital from 2015 to 2020 were retrospectively analyzed. A total of 828 patients were counted, including 532 cases of simple dislocation, 35 cases of complex surgical neck fracture with shoulder dislocation, 261 cases of shoulder dislocation combined with fracture of the greater tuberosity of the humerus, 28 cases without reduction data, and 230 cases of manual reduction. Before manual reduction, all patients underwent an X-ray examination and shoulder CT scan. The X-ray and CT data of 230 cases before reduction were obtained. Carefully interpret the X-ray images after reduction, confirm that the glenohumeral joint is well aligned and there is no aggravation of fractures, no subluxation, etc., count the reduction physicians and reduction methods, and carefully interpret the direction of the fracture line on the transverse CT image. According to the direction of the fracture line on the CT image, 230 manual reduction cases were divided into groups: A and B. There were 4 cases in group A, 226 cases in group B, and 4 cases of iatrogenic fractures in group A. Group A was when the anterior shoulder fracture line crossed the intertuberous groove. Group B was when the fracture line did not cross the intertuberous groove. The number of cases of iatrogenic fractures in the two groups of patients during manual reduction was counted, and the RR values of the two cases were calculated. At the same time, CT images of 35 patients with a shoulder dislocation and surgical neck fracture of the humerus were obtained, and the direction of the fracture line was observed.

Among the 230 patients who underwent manual reduction, 222 patients underwent manual reduction under anesthesia in the emergency department, and the reduction methods were the foot pedal or Milch maneuver. Eight patients underwent manual reduction under general anesthesia, three underwent open reduction, and one had a brachial plexus injury. Open reduction was performed, 2 cases of refractory shoulder dislocation received open reduction, 3 cases of iatrogenic fractures caused by manual reduction in the emergency room, 1 case of iatrogenic fractures caused by manual reduction under general anesthesia, and 1 case of iatrogenic fractures caused by manual reduction. The incidence rate was 1.8%. After analyzing the CT data, there were 4 cases of iatrogenic fractures in group A, with malalignment of the glenohumeral joint and fracture of the anatomical neck of the humerus. The fracture did not worsen. Statistical analysis was performed on the two groups of cases, and the RR value was calculated as 0. In an analysis of shoulder dislocation cases with complex proximal humerus fractures, it was found that in all 35 cases, the anterior shoulder fracture line passed through the intertuberous groove of the humerus on CT images.

The risk of iatrogenic fracture of shoulder dislocation with fracture of the greater tubercle of the humerus in the emergency room is low. CT scan of the shoulder joint is an effective method that can quickly identify cases of the iatrogenic fracture without three-dimensional reconstruction and reduce iatrogenic injury.