Primary Total Ankle Replacement for Acute Comminuted Pilon Fractures in Older Adults: Proposed Indications and a Report of 29 Cases.

Abstract

Management of severe distal tibia pilon fractures (AO/OTA 43-C3) in older adults is exceptionally challenging. Open reduction and internal fixation is associated with a high incidence of posttraumatic arthritis, whereas primary arthrodesis results in significant functional limitations. We investigated primary total ankle replacement (TAR) as a definitive, single-stage, motion-preserving solution. We retrospectively reviewed 29 older adult patients (age ≥60 years) treated with primary TAR since 2016 for comminuted pilon fractures. Inclusion required severe articular destruction (AO/OTA 43-C2/C3) but a reconstructable metaphyseal cortical shell. We evaluated surgical timing, adjunctive fixation, bone grafting, and clinical and radiographic outcomes. The primary outcome was the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score at ≥6 months. At 6 months post-surgery, the mean AOFAS score was 85.2 ± 7.5. Metaphyseal fracture union was achieved in all cases at an average of 17.4 ± 2.1 weeks. Postoperative alignment was excellent, with a mean medial distal tibial angle (MDTA) of 89.2° ± 1.8°. No deep infections, insert dislocations, or component overhang were observed. Three patients (10.3%) developed progressive valgus deformity, with MDTA increasing by an average of 3.4° at 1 year. In this retrospective level IV series with short-term follow-up, primary TAR may be a feasible option for carefully selected older adult patients with comminuted pilon fractures and a preserved metaphyseal cortical shell, demonstrating encouraging early functional outcomes. Longer term follow-up is required to determine implant survivorship and revision risk.