Acromioclavicular joint injury is the most common type of shoulder joint injuries. Approximately 9%-12% of patients with scapular injuries are acromioclavicular joints injuries. Every year, it is estimated that 1.8 per 1,000 people will be found acromioclavicular joint injury. Most of the patients are young people or people with some intensity of activity, especially athletes engaged in high-intensity confrontation sports, the proportion has reached 43% -50%. Most acromioclavicular joint injuries are caused by direct impact on the shoulder joint with greater force, such as landing on the shoulder joint while falling or traffic accident. At the time of trauma, the shoulder joint is in the adduction position or, in a few cases, the upper arm passive external rotation. In the process of injury, the elbow joint or hand is kept in a continuous straight position, making the humeral head move upward and impinges on the acromion, which is easy to cause dislocation of the acromioclavicular joint. However, we found from clinical practice and literature reports that, under the direct and indirect injury mechanism, scapular injury is not only the single acromioclavicular joint injury, but also may be associated with the surrounding tissue injury of glenohumeral joint. Especially after arthroscopic treatment of acromioclavicular joint dislocation has been paid more attention to, diagnostic arthroscopy can more clearly and accurately identify the surrounding tissue injuries of glenohumeral joint in addition to acromioclavicular joint injury. The acromioclavicular joint is easy to be damaged when the impact conduction of large force passes through the shoulder joint. However, the remaining impact energy will continue to affect and even destroy the tissue around the acromioclavicular joint, resulting in damage to the surrounding tissue, such as SLAP injury, Bankart injury, rotator cuff injury, etc. Because the injury mechanism of acromioclavicular joint injury is similar to that of combined injury, and the pain of acromioclavicular joint mostly covers the symptoms of combined injury, the symptoms of acromioclavicular joint injury tend to cover the possible complications. As a result, only acromioclavicular joint injury was managed in the treatment. Therefore, when patients have persistent postoperative shoulder pain or the improvement of shoulder joint activity is not obvious, we should be alert to the presence of shoulder joint complications. At present, the diagnostic examination under arthroscopy is sensitive and specific shoulder joint complications, and timely screening and surgical treatment of surrounding tissue injuries of glenohumeral joint is of great significance to the prognosis in this type of patients after surgery.

To understand the situation and prognosis of acromioclavicular joint injury combined with surrounding tissue injury of glenohumeral joint, and to analyze and discuss the causes of various comorbidities.

Fifty-two cases of acromioclavicular joint injuries were recorded. Rockwood classification, injury mechanism, VAS score at 12 months before and after operation, and Constant scores at 2, 6, and 12 months after operation were recorded.

In 52 patients, the combined injuries accounted for 32.69%, and 11 patients underwent additional surgical treatment. There was no statistically significant difference in VAS scores before and after surgery (P>0.05) . After 12 months of follow-up, the Constant score of patients with glenohumeral joint combined injury undergoing surgical treatment was not better than that of patients without additional surgical treatment (P>0.05) .

When treating the acromioclavicular joint, it is important to carefully examine whether there is a combined injury. Timely surgical treatment for combined injuries is of great significance to the recovery of shoulder joint function.