Talus Fracture of the Medial Tubercle of the Posterior Process: Interposition of the Flexor Hallucis Longus Tendon.

Talus fracture of the medial tubercle of the posterior process is rare. This type of fracture can be easily missed, because it is difficult to identify on plain radiographs of the ankle. Oblique radiographs with external rotation, computed tomography, and magnetic resonance imaging (MRI) of the ankle are useful for making an accurate diagnosis. However, even with an early diagnosis, the treatment guidelines for talus fractures of the posterior medial tubercle have not yet been established. The flexor hallucis longus (FHL) tendon, which passes through the groove between the medial and lateral tubercles of the posterior process of the talus, can interpose between the fracture sites and interrupt fracture reduction. MRI might be the best imaging modality for the identification of the interposed FHL tendon. We report a case in which talus fracture of the posterior medial tubercle was treated by open reduction and internal fixation owing to an interposed FHL tendon that was confirmed by MRI. MRI is the recommended imaging study of choice for talus fractures of the posterior medial tubercle owing to the possibility of an interposed FHL tendon.