Displaced intra-articular fractures of the tarsal navicular.

Between 1980 and 1987, twenty-one patients who had a displaced fracture of the body of the tarsal navicular were treated with open reduction and internal fixation. A classification system was devised on the basis of the direction of the fracture line, the pattern of disruption of the surrounding joints, and the direction of displacement of the foot. In a Type-1 injury, the fracture line is in the coronal plane and there is no angulation of the fore part of the foot. In a Type-2 fracture, the primary fracture line is dorsal-lateral to plantar-medial, and the major fragment and the fore part of the foot are displaced medially. In a Type-3 injury, there is a comminuted fracture in the sagittal plane of the body of the tarsal navicular, and the fore part of the foot is laterally displaced. Satisfactory reduction, which was defined as restoration of more than 60 per cent of the joint surface in the anteroposterior and lateral planes, was achieved in all Type-1 injuries, 67 per cent of the Type-2 fractures, and 50 per cent of the Type-3 fractures. Radiographic evidence of healing was seen at an average of 8.5 weeks after injury. At an average follow-up of forty-four months (range, twelve to 106 months), a good result was noted in fourteen patients (67 per cent); a fair result, in four (19 per cent); and a poor result, in three (14 per cent). Both the type of fracture and the accuracy of the operative reduction directly correlated with the final clinical outcome.