Introduction Posterior sternoclavicular dislocation must be diagnosed and treated early to prevent disastrous complications. The low frequency of this lesion means that it is rarely suspected, and diagnosis is often erroneous. Plain radiographs of the injury are difficult to interpret. Patients and methods We present a retrospective review of four cases treated in our department with closed reduction and a figure-of-eight bandage. The patients were studied using plain radiography and computed axial tomography. Results After 12 months of follow-up, the functional outcome according to the Rockwood scale was excellent. Discussion Although one of the most dangerous joint injuries, posterosternoclavicular dislocation can be cured with excellent functional outcome and minimal complications if diagnosis is prompt and adequate closed reduction is performed.