Posterior sternoclavicular joint dislocation is a rare condition. In this paper, we present a 51-year-old male patient who was admitted to the emergency department in our hospital after he was hit by a mining railway wagon in the chest. A diagnosis of posterior sternoclavicular dislocation was confirmed after performing a CT scan. Following necessary preparations, the sternoclavicular joint was stabilized with two wire cerclage techniques during open reduction. During control at the postoperative 4th week, the range of motion at the shoulder was satisfactory, but the patient had mild pain at the joint level and was sent to physical therapy to improve the range of motion and to minimize the pain.