Critical factors in enhancing the correction efficacy for varus talar tilt in patients with varus ankle osteoarthritis: relative fibular shortening to the tibia and syndesmotic widening.

INTRODUCTION

Relative fibular shortening compared to the tibia and syndesmotic widening are recognized contributors to the valgus tilt of the talus. This study aimed to assess: (1) the impact of fibular shortening relative to the tibia; and (2) the influence of syndesmotic widening, in correcting a large varus talar tilt (TT) associated with advanced ankle osteoarthritis through medial opening wedge valgization supramalleolar osteotomy (SMO).

MATERIALS AND METHODS

We retrospectively reviewed the clinico-radiographic findings of 41 patients with a preoperative TT of 8 degrees or more who underwent SMO for varus ankle osteoarthritis, with a minimum follow-up of more than two years. We compared several clinico-radiographic parameters between the three groups based on postoperative TT changes (decreased TT by 2 degrees or more, no TT changes [TT change between - 2 and 2 degrees], and increased TT by 2 degrees or more).

RESULTS

In total, 18, 16, and 7 patients were included in the groups with postoperative decreased TT, no TT changes, and postoperative increased TT, respectively. The postoperative talocrural angle was greater in the postoperative increased TT group than in the postoperative decreased TT group (P =.036). The postoperative tibiofibular clear space was greatest in the postoperative decreased TT group (P =.037), whereas the other two groups were not significantly different (P =.260). In the postoperative increased TT group, postoperative tibial plafond inclination was the lowest among the three groups (P =.048 and 0.023, respectively), indicating the greatest plafond valgus inclination to the ground. All postoperative clinical parameters were significantly lower in the postoperative increased TT group (P <.05).

CONCLUSION

When performing SMO for varus ankle osteoarthritis, TT correction might be associated with the relative length of the fibula to the tibia and the role of the syndesmosis, implying the need for fibular shortening/valgization and syndesmotic widening. Additionally, excessive correction during SMO that places the tibial plafond in a valgus position relative to the ground floor can paradoxically increase TT and exacerbate ankle osteoarthritis.

LEVEL OF EVIDENCE

Level III.