Isolated Tarsal Navicular Fracture-dislocation

Nine cases of fracture-dislocation of the tarsal navicular are reported. Six patients were male and three were female. Their mean age at the time of injury was 30.4 years old. The cause of the injury was a traffic accident in five cases and a fall from a height in four. Open reduction and internal fixation was performed in four cases (three by Kirschner wire, one by screw) and plaster fixation in four. Bony union was achieved in every case, except one chronic case. Arthropathic change was observed in two cases. No aseptic necrosis was found at follow-up. Pain on walking persisted in two cases. None of the patients complained of significant interference with ADL. Fracture-dislocations of the tarsal navicular are very rare, because the tarsal navicular is a small bone that is protected by surrounding bones and tightly bound by strong ligaments. These fractures usually occur in combination with fracture-dislocation ofLisfranc'sjoint, because forces great enough to cause fracture-dislocation of the tarsal navicular cause other fracture-dislocations at weaker sites. Thus, isolated navicular fracture-dislocation is extremely rare. Fractures without significant displacement were treated conservatively by plaster cast. Fracture-dislocations were reduced surgically and fixed internally, because manual reduction was difficult and dislocation was prone to recur.