Foot & Ankle
With the weekend weather improving and people increasingly enjoying the fresh air, accident and emergency departments become inundated with people slipping on wet or uneven surfaces breaking their ankles. The management of ankle fractures is becoming increasingly understood however, there continues to be a degree of debate regarding the use prophylaxis for the prevention of venous thromboembolism following treatment.
Our trust provides a flow diagram based upon the NICE guidelines.1 For unstable fractures having sustained trauma, the patient is allocated to be surgical, with a combined anaesthetic/surgical time of over 90 minutes and operative time in the absence of fracture pattern complexity is likely to be under 60 minutes. Following fixation, a cast will be applied and although usually full weight bearing as tolerated, mobilisation is likely to be reduced for more than three days. In our trust the guidance based upon these factors is that Low Molecular Weight Heparin should be administered with a thromboembolic deterrent stocking on the opposite leg.
But what is the actual incidence of VTE in this cohort of patients?
Patil et al2 assessed 100 patients who had an ankle fracture, using colour doppler duplex ultrasound. Five patients had a deep venous thrombosis (DVT) although none had clinical signs, no patients developed features of pulmonary embolism. A randomized placebo controlled double blind study has shown that the overall incidence of DVT based on unilateral phlebography was 21% with dalteparin prophylaxis compared with 28% in the placebo arm. The interpretation of these results does not support the use of prophylaxis.3
Recent work from both sides of the Atlantic has concluded that unless patients are medically high risk, routine chemothromboprophylaxis may not be required.
A study of NHS data of 45 949 ankle fracture fixations revealed rates of 0.12% for DVT, 0.17% for PE with a mortality of 0.37%. Risk factors were increasing age and multiple co-morbidities. The authors conclude that there is no evidence that thromboprophylaxis reduces the risk and thus is not required.4
Griffiths et al5 recently compared the incidence of DVT in elective foot and ankle surgery with (1078 patients) 75mg aspirin thromboprophylaxis and without (1567 patients). The rate of VTE was found to be 0.42% with a worst case scenario rate of 1.43%. Once again routine use of chemoprophylaxis was not considered necessary.
Pelet et al6 performed a chart review of 2478 patients with surgically treated ankle fractures. A venous thromboembolic event was defined as a PE or DVT demonstrated with Doppler Ultrasound. They identified an overall incidence of 2.99% with 0.32% having PE. The authors state that the use of thromboprophylaxis has no apparent impact on the occurrence of VTE for those that did or did not have risk factors (3.68% vs. 3.55%) but highlight the need for further prospective studies.
The current evidence would therefore suggest that the use of chemoprophylaxis has no influence on the rates of VTE in patients treated surgically for ankle fractures. I will continue to aim for prompt internal fixation before swelling prevents surgery and early mobilisation. Now should I continue with a cast or what about one of those braces?....
Mr Mike Carmont, Consultant Orthopaedic Surgeon, Princess Royal Hospital, Shropshire, UK
References:
1. Reducing the risk of venous thromboembolism (DVT & PE) in patients admitted to hospital. Clinical Guidelines CG92. Issued: January 2010.
2. Patil S, Gandhi J, Curzon I, Hui AC. Incidence of deep venous thrombosis in patients with a fractured ankle treated in plaster cast. J Bone Joint Surg [Br] 2007;89-B:1340-3.
3. Lapidus Lj, Ponzer S, Elvin A, Levander C, Lafors G, Rosfors S, de Brie E. Prolonged thromoboprophylaxis with dalteparin during immoblisation after ankle fracture surgery: a randomized placebo controlled double blind study. Acta Orthop 2007;78:528-35.
4. Jameson SS, Augustine A, James P, Serrano-Pedroza I, Townshend D, Reed MR. Venous thrombolic events from foot and ankle surgery in the English National Health Service. J Bone Joint Surg [Br] 2011;93-B:490-7.
5. Griffiths JT, Matthews L, Pearce CJ, Calder JD. Incidence of venous thromboembolism in elective foot and ankle surgery with and without aspirin thromboprophylaxis. J Bone Joint Surg [Br] 2012;94-B:210-4.
6. Pelet S, Roger ME, Belzile EL, Bouchard M. The incidence of thromboembolic events in surgically treated ankle fracture. J Bone Joint Surg [Am] 2012;94-A:502-6.
