Introduction:
Subtalar dislocation is an uncommon lesion in traumatology chiefly when it concerns the lateral form. Surgical treatment is required when a fracture is related or the dislocation is irreducible. Even well treated, these dislocations progress unavoidably to subtalar arthrosis, which stays well tolerated.
Case report:
A 46-year-old male with irreducible lateral subtalar dislocation caused sustentaculum tali incarceration confirmed on computed tomography (CT). The patient underwent emergent open reduction and internal fixation; the sustentaculum tali was reduced and fixed with a compression screw. At 3 years, "American Orthopaedic Foot and Ankle Society Ankle-hindfoot" score was 86, and the functional result was considered excellent despite a Grade I subtalar osteoarthritis on the ankle X-ray.
Conclusion:
An irreducible subtalar dislocation is exceptionally due to the incarceration of sustentaculum tali. CT is of great interest for good fracture analysis and management planning. Anatomical reduction of the articular surfaces, stable osteosynthesis, sufficient immobilization, and a well-conducted rehabilitation are the only guarantors of a good functional outcome.