Repositional Subtalar Arthrodesis Combined With Supramalleolar Osteotomy for Late-Stage Varus Ankle Arthritis With Hindfoot Valgus.

BACKGROUND: Late-stage varus ankle arthritis is thought to be associated with varus of the tibial plafond and hindfoot. However, some late-stage varus arthritis show hindfoot valgus, which can be explained by subtalar subluxation with opposite directional motion between the talus and calcaneus. We hypothesized that late-stage varus ankle arthritis with hindfoot valgus could improve with repositional subtalar arthrodesis and supramalleolar osteotomy (SMO). The purpose of this study was to investigate the clinical and radiographic results of the repositional subtalar arthrodesis combined with SMO for late-stage varus ankle arthritis with hindfoot valgus.

METHODS: This study includes 16 consecutive patients (16 ankles) with late-stage varus ankle arthritis of Takakura stage 3-b and hindfoot valgus who were treated using repositional subtalar arthrodesis combined with SMO and followed for a minimum of 2 years. Clinical results were assessed with the visual analog scale (VAS) and the Foot Function Index (FFI). Radiographic results were assessed with standard parameters measured on weightbearing foot and ankle radiographs. Clinical and radiographic results were evaluated preoperatively and at the last follow-up.

RESULTS: VAS and FFI significantly improved after surgery. Mean talar tilt angle improved from 12.8 ± 2.8 degrees to 3.9 ± 3.1 degrees ( P < .001). Talus center migration and Meary angle significantly improved after surgery. Medial distal tibial angle, lateral talocalcaneal angle, hindfoot moment arm, and talonavicular coverage angle significantly changed after surgery. Radiographic stage improved in 15 ankles (93.8%) after surgery.

CONCLUSION: In this series with minimum 2-year follow-up, we found that late-stage (Takakura stage 3-b) varus ankle arthritis with hindfoot valgus clinically and radiographically improved with repositional subtalar arthrodesis combined with SMO.

LEVEL OF EVIDENCE: Level IV, prognostic.