Diagnosis of impingement of the acromion: 1. Symptoms and signs, the main symptoms include pain and limitation of movement, the pain arc test and the impingement test should be noted. MRI can estimate the condition of the retrieval joint, the lateral pattern of the unfused acromion, the subacromial bursa and the rostroscopic ligament of the shoulder. The pathological changes in the subacromial bursa and rostral shoulder ligament can be diagnosed. Treatment of acromion impingement: Conservative treatment: Most patients with stage I and II acromion impingement can be treated conservatively with rest, ice, ultrasound, oral anti-inflammatory and analgesic medications, subacromial glucocorticoid injections, physical therapy, and rotator cuff strengthening exercises. Patients who do not respond to formal conservative treatment for 3-6 months should undergo surgery. Open surgical treatment: 95% of rotator cuff injuries and 100% of SIS are attributed to the rotator cuff, thus the doctrine of acromioplasty has become the classic surgical method for shoulder impingement. However, this procedure has disadvantages such as high trauma, slow recovery, and postoperative deltoid weakness. Arthroscopic subacromial gap decompression: Since the first report of arthroscopic subacromial gap decompression in 1987, arthroscopic acromioplasty has been widely used in clinical practice and has become the preferred treatment for impingement of the acromion. Arthroscopic acromioplasty includes: cleaning of the inflamed subacromial bursa, removal of the rostral shoulder ligament, anterior subacromial decompression, removal of the subacromial tuberosity, and rotator cuff repair if necessary. In 2007, Tavema et al. reported the application of Topaz radiofrequency ablation technique for the treatment of supraspinatus tendinitis with clinical results similar to those of conventional acromioplasty combined with bursal cleaning, leading to the conclusion that radiofrequency ablation technique could be effective in the treatment of acromioclavicular impingement, while in 2012, Lu Yi et al. In 2012, a prospective randomized controlled study found no significant effect on clinical outcomes with or without the use of Topaz radiofrequency ablation. Since Neer first reported the use of anterior acromioplasty for the treatment of impingement syndrome, clinical follow-up has revealed that anterosuperior subluxation of the humeral head is a common complication after subacromial decompression and debridement for irreparable rotator cuff tears. Torrens C et al. performed this procedure on 33 athletes, and 77% were unable to perform overhead movements, possibly related to glenohumeral instability, and the loss of tissue protection such as the rostral shoulder ligament predisposed the humeral head to anterosuperior displacement. Hockman et al. performed a cadaveric biomechanical study to simulate a hemi-shoulder replacement in a patient with a large irreparable rotator cuff tear. Chen et al. demonstrated that the anterior superior displacement of the humeral head increased significantly after rostral shoulder ligament resection, and after strengthening the supraspinatus, infraspinatus and subscapularis muscles, the humeral head displacement was relatively reduced in all models, in which the humeral head displacement was relatively minimal in the model with strengthening of the supraspinatus and subscapularis muscles, and the humeral head movement was mainly stable. The author believes that acromioplasty with resection of the rostral shoulder ligament, which plays an important role in maintaining the stability of the humerus, causes displacement of the humeral head. At the same time, some scholars advocate preserving the CAL in the repair of giant rotator cuff tears.Appropriate protection of the rostral shoulder ligament or strengthening of the rotator cuff can effectively stabilize the shoulder joint while taking into account the treatment effect of acromioclavicular impingement sign. We validated the efficacy of arthroscopic release of the rostral shoulder ligament (i.e., preservation of the rostral ligament) in the minimally invasive treatment of acromioclavicular impingement through a prospective randomized controlled study. We found that in patients with impingement requiring surgical treatment, the use of acromioplasty combined with extensive subacromial bursal clearance resulted in a more satisfactory clinical outcome; intraoperative release of the rostroscapular ligament was less effective than rostroscapular ligament resection in the short term, but there was no significant difference in the long-term clinical outcome between the two, so we suggest that rostroscapular ligament release rather than resection be performed during surgery for impingement.