IntroductionPosterior sternoclavicular joint dislocations are extremely rare and emergent injuries.Presentation of caseWe presented a case of a seventeen-year-old male patient who was diagnosed with traumatic posterior dislocation. He underwent joint reconstruction using sternocleidomastoid tendon autograft, and the operation went well.DiscussionAt four-week and fourteen-week follow-up post-operatively revealed a surgical wound that healed well, regained stable sternoclavicular joint that was marked by a normal left sternoclavicular notch, full range of movement of the left shoulder and the pain subsided.ConclusionThese findings provide evidence that the method of joint reconstruction and augmentation may produce good outcome for posterior dislocation of the sternoclavicular joint.