Oblique Sliding Fibular Osteotomy as an Adjunct to Supramalleolar Osteotomy in Varus Ankle Osteoarthritis: Comparative Radiographic and Clinical Outcomes

Background: Previous studies have shown that fibular osteotomy can enhance correction of varus talar tilt (TT) in ankle osteoarthritis (OA) when combined with supramalleolar osteotomy (SMO). This study introduces a simplified and universally applicable oblique sliding fibular osteotomy (OSFO) technique suitable for joint-preserving procedures. Methods: This retrospective study included 22 patients with varus ankle OA and TT >10 degrees who underwent OSFO with SMO between January 2019 and June 2024, with a minimum of 1-year follow-up. For comparison, 42 patients who underwent SMO with either a medial opening wedge or lateral closing wedge fibular osteotomy were analyzed. Radiographic and clinical outcomes were compared across the 3 groups. Results: Postoperatively, with the numbers available, TT showed a significant decrease ( P = .012), the relative fibular length to the tibia decreased by approximately 7.5 mm ( P = .01), and fibular valgization averaged 6.4 degrees ( P = .01) in all 22 patients. All clinical outcome measures improved significantly ( P = .001). In the comparative analysis of the 3 types of fibular osteotomy, the decrease in talocrural angle was significantly greater in the OSFO and lateral closing wedge groups than in the medial opening wedge group ( P = .013). The degree of shortening of the relative fibular length to the tibia was smaller in the medial opening wedge group than in the OSFO and lateral closing wedge groups ( P = .017). We did not detect a significant difference in the degree of fibular valgization among the groups ( P = .591). Notably, improved TT, hindfoot alignment angle, and hindfoot alignment ratio outcomes were observed only in patients undergoing additional inframalleolar procedures in conjunction with OSFO. Conclusion: The OSFO technique appears to offer correction comparable to conventional fibular osteotomy techniques when combined with SMO. Although its clinicoradiographic correction is similar to that of conventional lateral closing-wedge fibular osteotomy, the OSFO technique could offer intraoperative adjustability and eliminate the need for plate fixation, providing distinct surgical advantages.