Case: We present the case of a 41-year-old man with a displaced extra-articular proximal-third clavicle fracture managed with open reduction and double-plate internal fixation. Twelve months after the procedure, the patient had recovered full range of motion and returned to work. Conclusions: Proximal-third clavicle fractures are infrequent injuries and are usually treated conservatively. They are associated with thoracic injuries or high-energy dorsal or cervical spinal trauma. In the case of displaced fractures and small medial fragments, orthopaedic management may have unsatisfactory results, creating symptomatic nonunions and functional limitation, we propose a biplanar osteosynthesis, which could be an effective treatment.