Incidence of clinically relevant venous thromboembolism after foot & ankle surgery

T.A. Ball, M. Daoud, E. Jabil, R. Kincaid

Introduction: Surgeons want to counsel their patients accurately about the risks of rare complications. This is difficult for venous thromboembolism (VTE), as most studies report rates of asymptomatic disease, which may not be clinically relevant. Generic guidelines promote chemoprophylaxis in foot and ankle surgery despite a relative dearth of evidence. We therefore calculated the rate of confirmed, symptomatic deep vein thrombosis and pulmonary embolism, after surgery or trauma to the foot or ankle, in our hospital.

Methods: In a retrospective cohort design, we scrutinised referrals for venous Doppler ultrasound and computed tomography pulmonary angiography, and found all confirmed deep vein thromboses (DVTs) or pulmonary embolisms (PEs) over an 18 month period from November 2010 to May 2012. These patients were cross-referenced with our orthopaedic database. All adult trauma admissions and fracture clinic attendances were retrieved and divided according to injury. We then identified all adult elective patients using Healthcare Resource Group code data.

Results: Out of 1763 elective foot and ankle procedures, there were five DVTs (incidence 0.28%) and no PEs. Out of 1970 patients with ankle fractures, seventeen (0.86%) sustained DVTs (thirteen conservatively, four operatively managed) and five PEs (0.25%). Of 147 patients with Achilles tendon rupture, three (2%) had a DVT and two (1.36%) a PE (p< 0.05). Summing together all fractures of the foot, of 1775 patients, two (0.05%) had a DVT and there were no PEs.

Conclusion: Currently this group of patients does not routinely receive anticoagulants. The relatively low incidence of symptomatic VTE is reassuring and will help to inform surgeons when considering the risks and benefits of anticoagulation. However, Achilles rupture is confirmed as a higher risk injury, which therefore is more likely to benefit from either increased vigilance or anticoagulation. Large randomised trials measuring clinically relevant VTE (rather than asymptomatic DVT) are needed.