Abstract
Tibiotalocalcaneal (TTC) arthrodesis using a retrograde nail is a common salvage procedure for a range of indications. Previous work has suggested subtalar joint preparation is unnecessary to achieve satisfactory results. We examine the incidence of symptomatic subtalar nonunion following tibiotalocalcaneal fusion in a series of patients, all of whom had full preparation of the subtalar joint, and consider the possible contributing factors.
We performed a retrospective review of all patients who underwent TTC arthrodesis from 2004–2010. All fusions were performed by the same surgeon with full preparation of both tibiotalar and subtalar joints.
61 TTC arthrodeses were performed in 55 patients (mean age = 59 years) using an intramedullary retrograde nail. Mean follow-up was 18 months (6–48 months). Fifty-six ankles (92%) achieved satisfactory union. Five patients (8%) had symptomatic non-union: 4 patients of the subtalar joint - with 3 patients undergoing revision subtalar arthrodesis and 1 patient of the tibiotalar joint. Nine patients required removal of the calcaneal screw (16%) – all had evidence of isolated subtalar nonunion prior to metalwork failure. Eight of these patients achieved asymptomatic union following screw removal.
Subtalar nonunion following TTC fusion has resulted in recent changes to nail design to increase stability across the subtalar joint. Our results demonstrate a favourable overall nonunion rate with isolated subtalar nonunion making up the majority of cases. We also observed a significant rate of distal screw loosening, also associated with subtalar nonunion prior to screw removal, the significance of which merits further investigation.
