Posterior sternoclavicular Salter-Harris fracture-dislocation in a patient with unossified medial clavicle epiphysis

Sternoclavicular injuries are relatively rare, composing less than 1 % of all musculoskeletal fractures or dislocations. When sternoclavicular injuries do occur, they typically present as an isolated dislocation of the sternoclavicular joint without associated fracture of the clavicle or manubrium. However, in patients with unfused medial clavicle physis, sternoclavicular joint injuries can present as a fracture-dislocation through the unfused physis. These physeal injuries are important to recognize as the displaced epiphysis can block reduction of the sternoclavicular joint. We present a case of a 15-year-old female basketball player presenting with suspected sternoclavicular joint injury after sustaining a direct blow to the left shoulder. An initial shoulder CT confirmed the presence of the clinically suspected posterior sternoclavicular dislocation without fracture identified. An MRI of the left sternoclavicular joint was then performed for suspected physeal fracture, which confirmed the presence of a fracture through the medial clavicle physis with anterior displacement of the unossified epiphysis, blocking reduction of the metaphysis. Given the findings on MRI, the pediatric orthropedic surgeon was able to counsel the family of the high likelihood of failed closed reduction of the sternoclavicular joint requiring conversion to open reduction and internal fixation. The patient underwent successful open reduction and internal fixation of the medial clavical physeal fracture after an initial gentle attempt at closed reduction was unsuccessful.