Object To analyze reasons of complications induced by the clavicle hook plate in treatment of acute distal clavicle fractures and acute acromioclavicular joint dislocations,and to investigate corresponding solutions.Methods Seventy nine clavicle hook plates were facilitated in the treatment of acuteb distal clavicle fractures (47 cases) and acute high grade acromioclavicular joint dislocations (32 cases) from May 2006 to May 2009.There were 51 males and 28 females,with an average age of 42.6 years(range,15 to 78 years).Seventy eight patients underwent plate removal operation.Forty patients agreed to accept the CT examination to evaluate the acromion erosion around the plates.Among them,7 patients received further CT examination 3 months after the removal surgery.The shoulder function was evaluated by the constant scores at the final follow-up.Results All patients were followed up for at least one year (range,12 to 30 months).The mean duration for retaining the hook plate was 8.3 months with the mean Constant scores 92 points in the acute distal clavicle group; 7.2 months with the mean Constant scores 95 points in the acute acromioclavicular joint dislocation group.There were 8 kinds,totally 105 complications happened in 78 patients (98.7％).The complications were classified into four groups: (1) Due to the specific working mechanism of the plate(88/105,83.8％);(2) Due to the iatrogenic errors(12/105,11.4 ％);(3) Due to insufficiency design of the plate(3/105,2.9％);(4) Due to the etiology of the injury itself(2/105,1.9％).Conclusion The complication rate is unexpected higher.Most complications are unavoidable due to specific working mechanism of the plate.The patients should be well informed about this preoperatively in order to avoid the possible legal trouble.The iatrogenic errors can be avoided with proper indications and improved surgical techniques.The design of the plate needs to be improved,and the hook plate should be removed as early as possible.