In conclusion, we believe that the clavicular hook plate is useful for treating unstable clavicle fracture or AC dislocation. However, the adverse effects of the implant imposed on subacromial structures influence the patient's final functional outcome. Careful patient selection and familiarity with the special features of implant as well as surgical technique are prerequisites for good clinical results with few complications. Musculoskeletal sonography can provide useful information regarding shoulder anatomic and functional kinematics in patients who receive clavicular hook plate fixation