PURPOSE: The purpose of this study was to present methods and results for the modified Phemister operation, with a suture anchor added for augmentation of the conoid ligament in cases of acute dislocation of the acromioclavicular joint. MATERIALS AND METHODS: We evaluated 14 cases of acute dislocation of the acromioclavicular joint. This included 11 cases of Rockwood type 3, and 3 cases of type 5. The mean age of patients was 45.2 years. We operated on them using an anchor for augmentation of the conoid ligament in the modified Phemister operation. The average follow-up period was 14 months and post-operative clinical analysis was conducted using the Weitzman classification, VAS Score, Constant Score and KSS Score. RESULTS: According to Weitzman scores, 13 cases were evaluated as excellent, and one case was good. They had mean joint ranges of forward elevation of 170.7degrees, lateral elevation of 166.4, external rotation of 68.2, and internal rotation to the level of T7. The mean VAS Score was 1.9, mean Constant Score 90.8, and the mean KSS Score 91. Radiologic analysis indicated that all cases had a good result. CONCLUSION: The modified Phemister operation with a suture anchor added for augmentation of the conoid ligament is very effective clinically in acute dislocations of the acromioclavicular joint.