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

Abstract

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. 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. Postoperatively, with the numbers available, TT showed a significant decrease (<i>P</i> = .012), the relative fibular length to the tibia decreased by approximately 7.5 mm (<i>P</i> = .01), and fibular valgization averaged 6.4 degrees (<i>P</i> = .01) in all 22 patients. All clinical outcome measures improved significantly (<i>P</i> = .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 (<i>P</i> = .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 (<i>P</i> = .017). We did not detect a significant difference in the degree of fibular valgization among the groups (<i>P</i> = .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. 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.