OBJECTIVE To investigate the clinical efficacy, complications and necessity of removing internal fixation in treatment of fresh Tossy type III acromioclavicular joint dislocations and Neer type II distal clavicle fractures with clavicular hook plate. METHODS From June 2005 to June 2008, 24 patients with fresh Tossy type III acromioclavicular joint dislocations and 20 patients with fresh Neer type II distal clavicle fractures were treated. There were 32 males and 12 females with an age range of 18-66 years (38.5 years on average), involving 18 left shoulders and 26 right shoulders. The injury was caused by traffic accident in 31 cases and by falling in 13 cases. The mean time from injury to operation was 4 days (range, 2-8 days). All patients were treated by reduction with clavicular hook plate fixation. The coracoclavicular ligaments were not sutured. The shoulder functions were evaluated according to University of California-Los Angeles (UCLA) score system and analysed before and after removing internal fixation. RESULTS Wound infection occurred in 2 cases 1 week after operation and healed after symptomatic management, the other incisions healed by first intention. One case accepted hook plate fixation again because of loosening hooking-up 1 week after operation. One case accepted hook plate removal and Kirschner wire fixation because of severe shoulder's pain on the postoperative third day. Thirty-eight patients were followed up for 8-32 months (18 months on average), there was no plate breakage. Clavicle fractures got bony union after 3-6 months (4.2 months on average). At last follow-up (before plate removal), according to UCLA shoulder function score system, the results were excellent in 11 cases, good in 22 cases, and fair in 5 cases; the excellent and good rate was 86.8%. Because of shoulder's pain, plates were removed in 20 patients 3-16 months (10 months on average) after operation. The cases were followed up 3-8 months (5 months on average) after removing plate. No dislocation and fracture occurred again. There was statistically significant difference (P < 0.01) in the functional scores of shoulder between before (30.55 +/- 4.00) and after removing internal fixation (33.85 +/- 1.95). CONCLUSIONS Clavicular hook plate fixation is an effective treatment for fresh Tossy type III acromioclavicular joint dislocations and Neer type II distal clavicle fractures. Normative operating, correct plate moulding, functional rehabilitation after operation are key factors in preventing complications and reaching good clinical efficacy. For the patients with postoperative symptoms, the plate should be removed to improve the shoulder's function.