Chronic Instability following Isolated Subtalar Dislocations: a Case Series and Proposal for Routine MRI.

Purpose of the study: Subtalar dislocations are rare orthopedic emergencies characterized by simultaneous dislocation of the talocalcaneal and talonavicular joints without an associated talar neck fracture. While these injuries are commonly managed with closed reduction and immobilization, they are often associated with chronic instability and other long-term complications due to underdiagnosed soft tissue injuries.This study aims to evaluate the role of magnetic resonance imaging (MRI) in the management of isolated medial subtalar dislocations and propose a routine MRI protocol to predict and address chronic instability.

Material and methods: A prospective case series was conducted, including 13 patients with isolated medial subtalar dislocations. All patients underwent MRI to assess soft tissue injuries, particularly the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL). Functional outcomes were evaluated using the Visual Analog Scale (VAS) for pain and the American Orthopaedic Foot & Ankle Society (AOFAS) scores.

Results: MRI identified complete or partial tears of the CFL and ATFL in the majority of patients. Patients with complete ligament tears reported worse outcomes, with lower AOFAS scores and higher VAS pain scores, compared to those with partial or no ligament involvement. Conservative management was effective in mild cases, while surgical reconstruction was required for patients with significant instability.

Conclusions: Routine MRI in the management of isolated subtalar dislocations enhances the detection of soft tissue injuries, facilitating timely interventions and reducing the risk of chronic instability. Integration of MRI into the diagnostic and follow-up protocol for improved patient outcomes.