Repair of the Nonunion of the Lateral Process of the Talus Will Improve Osteoarthritis of the Subtalar Joint: A Case Report.

Fracture of the lateral process of the talus (FLPT) is a rare injury. FLPT is frequently missed or diagnosed late, often leading to nonunion, malunion, or subtalar osteoarthritis. We present a case of a 44-year-old male with schizophrenia who sustained an FLPT after falling downstairs. Initial radiographs missed the injury, and conservative treatment was pursued despite the presence of bone fragments. After four months, persistent pain led to further imaging, revealing subtalar joint osteoarthritis. Surgical intervention was required due to nonunion and large, displaced bone fragments. A 4 cm incision was made, and the fracture site was refreshed and fixed using screws with bone grafting. Postoperatively, the patient showed significant improvement, with complete bone union and enhanced joint space after one year. At the last follow-up (three years after surgery), the patient was able to work without difficulty. Late diagnosis and non-aggressive treatment can lead to poor prognosis, with late complications, including nonunion, malunion, bony overgrowth, and subtalar osteoarthritis. We presented a case of nonunion of the lateral process of the talus with osteoarthritis of the subtalar joint. A good clinical outcome was achieved by fixing the fracture and stabilizing the subtalar joint.