A 48-year-old woman is struck by a motor vehicle on her left tibia. Plain radiographs show a fracture of the tibial shaft with multiple bone fragments, several of which are completely separated from the main proximal and distal fragments. The fracture involves more than 50% of the bone width. Additionally, there is significant soft tissue damage with an open wound over the fracture site. According to the AO/OTA classification system, what is the primary fracture type?