The patient and surgical factors specific to patients not receiving anticoagulation when undergoing foot and ankle surgery in the UK - UK-FATE Audit

K. Malhotra, J. Mangwani, L. Mason, L. Houchen-Wolloff

Introduction: Although the rate of VTE after foot and ankle surgery is low, there are multiple factors influencing the risk for individual patients. Furthermore, there are no clear guidelines on which patients may benefit from chemical thromboprophylaxis (CTP). Our aim was to assess patients not treated with chemical thromboprophylaxis when undergoing foot and ankle surgery, to report on their specific patient and surgical risk factors for VTE.

Methods: This was a multi-centre, prospective, national audit of patients undergoing foot and ankle surgery (including Achilles tendon ruptures) from 68 participating UK centres. The study was from 1st June 2022 and 30th November 2022, with a further 3-month follow up. Data on a total of 13,569 patients was submitted. Following data cleansing, 11,363 patients were included for further analysis.

Results: CTP was not given in 3,717 (32.71%) patients. The overall VTE rate in patients without prophylaxis was 0.36% (13 cases) versus 1.1% (86 cases) in patients given CTP (Odd’s ratio 3.18, p<0.001). Overall, 2,876 elective patients (56.5%), 551 trauma patients (11.5%), 148 acute diabetic foot patients (37.2%), 142 Achilles rupture patients (13.1%) did not receive CTP, with VTE rates 0.1%, 0.5%, 0.0%, and 4.2% respectively (Odd’s ratio 38.2 for Achilles ruptures, p<0.001). In patients not receiving prophylaxis, a smaller proportion had increased surgical urgency (20.7% vs 59.7%, p<0.001), were non-weightbearing (8.5% vs 74.3%, p<0.001), or required post-operative splintage (24.5% vs 79.7%, p<0.001) compared to those not receiving CTP.

Conclusion: Patients not receiving CTP in this audit had a low incidence of VTE. Without adjustment for variables, this is lower than patients given prophylaxis. However, these patients represent a curated group considered lower risk - including less urgent surgery, early weightbearing and lack of post-operative splinting. Despite these factors Achilles tendon ruptures were associated with a significantly higher VTE rate.