Talus and subtalar joint injuries Overview
The talus is a largely articular hindfoot bone that transmits axial load from the tibia to the calcaneus and navicular. Because most of its surface is covered by cartilage and its blood supply is tenuous, talar fractures and subtalar dislocations are high‑risk injuries.
They commonly follow high‑energy mechanisms, frequently involve joints, and carry significant risks of avascular necrosis (AVN), post‑traumatic arthritis and long‑term hindfoot disability.
Displaced, intra‑articular or open talar injuries usually need urgent orthopaedic (often orthoplastic) input, advanced imaging and commonly operative fixation.
Anatomy and biomechanics
- The tarsus comprises hindfoot bones (talus, calcaneus) and midfoot bones (navicular, cuboid, three cuneiforms).
- The talus lies between the tibia/fibula superiorly, the calcaneus inferiorly (subtalar joint) and the navicular anteriorly (talonavicular joint).
- Most talar surfaces are covered by cartilage and there are no muscle attachments; vascular supply is limited and derived from branches of the posterior tibial, dorsalis pedis/anterior tibial and perforating peroneal arteries. This limited blood supply explains the talus' susceptibility to AVN after fracture.
- The subtalar joint (talus-calcaneus) is key for inversion/eversion and overall hindfoot mechanics.
Mechanism
- Typical mechanisms are high‑energy axial loading with forced dorsiflexion or plantarflexion (motor vehicle collisions, falls).
- Lower‑energy mechanisms (sporting injuries) can cause avulsion or process fractures.
- Subtalar dislocations usually result from inversion (medial dislocation) or eversion (lateral dislocation) forces;...