Clinical and Radiographic Outcomes of Fibula-Preserving Supramalleolar Osteotomy Combined with Arthroscopic Modified Broström Operation in Varus Ankle Osteoarthritis

Background and Objectives: Conventional supramalleolar osteotomy (SMO) often involves a concomitant fibular osteotomy (FO), which carries risks, such as nonunion and nerve injury. We evaluated the clinical and radiological outcomes of a fibula-preserving SMO (FP-SMO) combined with arthroscopic modified Broström operation (MBO) in patients with medial compartment varus ankle osteoarthritis and chronic lateral ankle instability. Materials and methods: We retrospectively reviewed 22 patients who underwent medial opening wedge FP-SMO and arthroscopic MBO between 2014 and 2019. Clinical outcomes were assessed using the Visual Analog Scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, and Foot and Ankle Outcome Score (FAOS). Radiological evaluation included the anterior drawer test (ADT), talar tilt angle, tibiotalar surface (TTS) angle, medial distal tibial angle (MDTA), tibial lateral surface (TLS) angle, Takakura stage, and International Cartilage Regeneration and Joint Preservation Society (ICRS) grade assessed during second-look arthroscopy. Results: At a mean follow-up of 17.22 months, the mean VAS, AOFAS, and FAOS scores improved significantly (p< 0.001). Radiologically, the mean ADT decreased from 5.98 mm to 4.70 mm (p = 0.015), and the mean talar tilt angle decreased from 9.85° to 6.09° (p< 0.001). The mean TTS angle increased from 80.46° to 84.86° (p = 0.021), and the mean MDTA increased from 85.03° to 91.26° (p< 0.001). The TLS angle showed no significant change from 81.17° to 81.54° (p = 0.238). Takakura stage and ICRS grade improved or remained stable in all patients. No major complications, including nonunion, were observed. Conclusions: FP-SMO combined with arthroscopic MBO demonstrated favorable short-term clinical and radiological outcomes in selected patients with medial compartment varus ankle osteoarthritis and chronic lateral ankle instability. This combined approach may be a feasible joint-preserving option that addresses coronal malalignment and lateral ankle instability without requiring FO; however, longer-term comparative studies are needed to confirm its durability and clinical utility.