Clinical Outcomes of Supramalleolar Osteotomy in Intermediate Stage of Varus Ankle Osteoarthritis in Joint Preservation

Abstract

Supramalleolar osteotomy (SMO) is an effective treatment for intermediate-stage varus ankle osteoarthritis (OA). This study aimed to investigate how clinical outcomes were associated with radiological changes and cartilage regeneration shown on arthroscopy before and after SMO in patients with intermediate-stage varus ankle OA. Twenty-six cases with intermediate-stage varus ankle OA underwent SMO with at least 1 year of postoperative follow-up. Clinical assessment was performed preoperatively and postoperatively using the visual analog scale (VAS), American Orthopedic Foot and Ankle Society ankle-hindfoot (AOFAS) scores, and their associations with postoperative changes in tibial ankle surface angle (TAS), talar tilt, tibial lateral surface angle, and heel alignment ratio. The degrees of cartilage regeneration in the tibia plafond and talar dome were observed via second-look arthroscopy. Afterward, their associations with the corresponding clinical outcomes were analyzed. There were significant changes in the TAS, talar tilt, and heel alignment ratio (p < .001, for all). However, there were no significant changes in the tibial lateral surface angle (p = .864) at the final follow-up compared to its preoperative value. Postoperative changes in TAS (p = .013) and the degree of cartilage regeneration (p = .028) in the talar dome significantly influenced the final follow-up AOFAS score. Changes in the TAS angle and the degree of cartilage regeneration after SMO were predictors of clinical outcomes after SMO. In particular, greater changes in the TAS angle corresponded to better clinical outcomes.