Talus Bipartitus: A Rare Anatomical Variant Presenting as an Entrapment Neuropathy of the Tibial Nerve within the Tarsal Tunnel

Abstract

Tarsal tunnel syndrome is an entrapment neuropathy of the tibial nerve within the tarsal tunnel that lies beneath the retinaculum on the medial side of the ankle. It is often underdiagnosed. Talus bipartitus is a rare anatomical variant; only a few cases have been described in medical literature. We report a case of a 36-year-old female with tarsal tunnel syndrome secondary to a talus bipartitus undergoing surgical treatment with good clinical outcome. To our knowledge, talus bipartitus presenting as tarsal tunnel syndrome has no previous reports. Image studies and physical examination are crucial to reach precise diagnosis.

Figure 1

X-ray of the hind foot, lateral view, showing a 1.8 cm accessory posterior bone fragment (arrow).

Figure 2

Comparative CT scan showing posterior bone process, displacing into the medial side (arrow) in both coronal (a) and axial (b) view.

Figure 3

MRI, sagittal view of the ankle; the presence of cartilage between the talar body and the accessory bone can be appreciated (stars).

Figure 4

Medial approach with exposure of the pseudoarticular space (star), tibialis posterior retracted forward (yellow arrow), and the accessory bone fragment (white arrow).

Figure 5

Comparative preoperative (a) and postoperative X-rays with no residual bone (b).