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.
Isolated talonavicular arthrodesis is a common procedure particularly for posttraumatic arthritis and rheumatoid arthritis. Two surgical approaches are commonly used: the medial and the dorsal approach. It is recognized that access to the lateral aspect of the talonavicular joint can be limited when using the medial approach and it is our experience that using the dorsal approach addresses this issue. We performed an anatomical study using cadaver specimens, to compare the amount of articular surface that can be accessed, and therefore prepared for arthodesis, by each surgical approach. Medial and dorsal approaches to the talonavicular joint were performed on each of 11 cadaveric specimens (10 fresh frozen, 1 embalmed). Distraction of the joint was performed as used intraoperatively for preparation of articular surfaces during talonavicular arthrodesis. The accessible area of articular surface was marked for each of the two approaches using a previous reported technique3. Disarticulation was performed and the marked surface area was quantified using an immersion digital microscribe, allowing a three dimensional virtual model of the articular surfaces to be assessed. The median percentage of accessible total talonavicular articular surface for the medial and dorsal approaches was 71% and 92% respectively. This difference was significant (Wilcoxon Signed Ranks Test, p<0.001). This study provides quantifiable measurements of the articular surface accessible by the medial and dorsal approaches to the talonavicular joint. These data support for the use of the dorsal approach for talonavicular arthrodesis.
