The benefit of pharmacological venous thromboprophylaxis in foot and ankle surgery

Ten percent of patients with a deep-vein thrombosis (DVT) will develop a fatal pulmonary embolism (PE), often initially asymptomatic. The risks and benefits of pharmacological thromboprophylaxis are well documented in respect of total joint arthroplasty and hip fractures, but little is understood about the incidence of venous thromboembolism (VTE) or the potential risks and benefits of chemoprophylaxis in foot and ankle surgery.

To determine whether prophylactic chemoprophylaxis had any impact on the prevention of VTE in a cohort of foot and ankle surgical patients requiring the combination of below-knee cast immobilisation and non-weightbearing for ≥4 weeks.

Between March 2014 and April 2015, a prospective cohort study of 142 patients was performed. All completed a thrombosis risk assessment form prior to surgery and were commenced on rivaroxaban (Xarelto) 10 mg/d postoperatively. The primary outcome measure was clinical VTE confirmed by compression ultrasonography (DVT) or a ventilation/perfusion scan (PE).

Three patients (2.1%) developed a clinical DVT. Two did so well beyond the immobilisation and anticoagulation period, and one was non-compliant with therapy. The average risk factor score in this subgroup was 7. No patient had a DVT while on the prescribed regimen of anticoagulant therapy. Five patients (3.5%) developed wound breakdown, two requiring surgical debridement with local skin flap closure. One case of menorrhagia that may have been linked to the anticoagulant therapy was reported. When compared with a previous study, pharmacological thromboprophylaxis significantly reduced VTE risk (p=0.02).

Oral pharmacological thromboprophylaxis significantly reduces the risk of VTE in patients requiring cast immobilisation and non-weightbearing following foot and ankle surgery. The risk/benefit ratio favours this treatment as opposed to the treatment of major morbidity following non-fatal VTE.