Rethinking Chemoprophylaxis for Total Ankle Replacement

Abstract

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) is a relatively uncommon joint replacement procedure. Only 631 TAR operations were performed in the UK in 2014. However, its popularity is increasing as a suitable alternative to ankle fusion in patients with end stage ankle arthritis. A rare complication of TAR surgery is the development of a Venous Thromboembolism (VTE), including Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). We sought to investigate the effectiveness of our own peri-operative management and VTE prophylaxis protocol in the prevention of symptomatic VTE, in patients undergoing TAR surgery in our tertiary referral hospital. Methods: We conducted a retrospective cohort study of prospectively collected data in patients undergoing TAR with Mobility TAR (Depuy™, Leeds, United Kingdom) between March 2006 and May 2012. All patients were treated according to a pre-defined protocol. Patients undergoing TAR were not given VTE prophylaxis unless there were specific indications of increased risk of VTE - such as cardiac risk factors or post-operative air travel. A Vacuum Assisted Closure (VAC™) device was applied post operatively to increase the speed of wound healing, creating a negative pressure environment preventing dehiscence. Patients were not immobilised post operatively but rested for 5 days with the index leg elevated, while ankle movement was encouraged. Patients were mobilised early (5-7days). We reviewed all post-operative clinical follow up for 6 months, the time chosen as a cut off for an incident of DVT to be attributable to the surgery. Results: A cohort of 200 TARs were assessed. The mean age of the cohort was 61.7 years of age (range 31.0-89.4). There were no recorded deaths. There were 125 male and 75 female patients with 85 Left and 115 Right TAR procedures performed. In total 31 patients (15.5%) were given chemoprophylaxis in the post-operative period on clinical grounds. 187 (73.4%) patients were mobilised early (5-7days) post-operatively; with 2 (0.8%) mobilised with partial weight bearing and 21 (4.6%) mobilised non-weight bearing. In the mobilised early subgroup of patients only 10 (5%) had problems and required subsequent immobilisation. The majority of post-operative problems were caused by post-operative peri-prosthetic fracture (n=8, 4%) and wound break down (n=2, 1%). Conclusion: This study highlights that there is a need for further research into the use of VTE prophylaxis in TAR. In addition we feel that chemoprophylaxis should not be considered the panacea for reducing the incidence of VTE in patients undergoing TAR. We suggest post-operative limb elevation, haematoma evacuation and use of VAC treatment should be prioritised with early mobilisation and full weight bearing. Furthermore this study suggests judicious VTE chemoprophylaxis should be given on clinicians’ judgement tailored to individual patient requirements. This will hopefully avoid unnecessary costs and possible complications of anticoagulation such as bleeding, delayed wound healing and thrombocytopenia.