Abstract
Introduction
Circular frames for ankle fusion are usually reserved for complex clinical scenarios. Current literature is heterogenous and difficult to interpret. We aimed to study the indications and outcomes of this procedure in detail.
Materials & Methods
A retrospective cohort study was performed based on a prospective database of frame surgeries performed in a tertiary institution. Inclusion criteria were patients undergoing complex ankle fusion with circular frames between 2005 and 2020, with a minimum 12-month follow up. Data were collected on patient demographics, surgical indications, comorbidities, surgical procedures, external fixator time (EFT), length of stay (LOS), radiological and clinical outcomes, and adverse events. Factors influencing radiological and clinical outcomes were analysed.
Results
47 patients were included, with a mean follow-up of three years. The mean age at time of surgery was 63.6 years. Patients had a median of two previous surgeries. The median LOS was 8.5 days, and median EFT was 237 days. Where simultaneous limb lengthening was performed, the average lengthening was 2.9cm, increasing the EFT by an average of 4 months. Primary and final union rates were 91.5% and 95.7% respectively. At last follow-up, ASAMI bone scores were excellent or good in 87.2%. ASAMI functional scores were good in 79.1%. Patient satisfaction was 83.7%. 97.7% of patients experienced adverse events, most commonly pin-site related, with major complications in 30.2% and re-operations in 60.5%. There were 3 amputations. Adverse events were associated with increased age, poor soft tissue condition, severe deformities, subtalar fusions, peripheral neuropathy, peripheral vascular disease, and prolonged EFT.
Conclusions
Complex ankle fusion using circular frames can achieve good outcomes in complicated clinical scenarios, however patients can expect a prolonged time in the frame and high rates of adverse events. Multiple risk factors were identified for poorer outcomes, which should be considered in patient counselling and prognostication.
