Challenging the evidence for graduated compression stockings

Is extended anticoagulation after knee replacement necessary in 2013?
Whittaker et al challenge the evidence for compression stockings in preventing
symptomatic venous thromboembolism (VTE). There may also be grounds to
question the benefits of prophylactic anticoagulation.1
Current National Institute for Health and Care Excellence (NICE)
recommendations advocate chemical prophylaxis for 10‐14 days following
elective total knee replacement (TKR), a procedure considered by many as high
risk for VTE. 2
The most significant consequence of VTE following TKR is fatal pulmonary
embolism (PE). Prior to the introduction of anticoagulants, the fatal PE rate was
0.1‐0.43%.3 The introduction of chemical thromboprophylaxis has not clearly
decreased the prevalence of PE with little advantage in using aspirin or
heparin.4,5
Early papers documented a 40‐60% prevalence of deep vein thrombosis (DVT)
following TKR. Concern existed about the connection between DVT and PE. But
their association is not strong. And surveys focused on asymptomatic DVTs, most
of which resolve spontaneously. Also, post‐thrombotic limb ulceration has not
featured in the literature.6 Current literature suggests a symptomatic DVT rate of
0.6% following TKR, using either aspirin or heparin.
Seeing is believing. Orthopaedic surgeons review patients for two or more years
after TKR .From a personal series of more than 800 knee replacements,
rehabilitated with next‐day walking and injected anticoagulants only whilst in
hospital, I am aware of 6 DVTs and 3 PEs, none fatal. Perhaps the answer lies in
rapid mobilisation. One study suggests that delaying walking by only one day
increases risks of VTE 30‐fold. 7
Post‐operative bleeding is more likely with anticoagulation, undermines wound
healing and risks deep infection, particularly in superficial joints such as the
knee.5 And shorter hospital stays will increase potential for evolving wound
problems to be missed.
The current default to provide extended thromboprophylaxis has a shaky
evidence base. Knee replacement is no longer strongly associated with DVT nor
PE.
As with compression stockings, perhaps NICE should review its guidelines.
References
1. Whittaker L, Baglin T, Vuylsteke A. Challenging the evidence for
graduated compression stockings. BMJ 2013;346:f3653.
2. National Institute for Health and Care Excellence. Venous
thromboembolism: reducing the risks of venous thromboembolism (deep
vein thrombosis and pulmonary embolism) in patients admitted to
hospital. CG92. 2010. http://guidance.nice.org.uk/CG92.
3. Warwick DJ, Whitehouse S. Symptomatic venous thromboembolism after
total knee replacement. J Bone Joint Surg Br. Vol 79‐B, No. 5 September
1997. 780‐786.
4. Cusick LA, Beverland DE. The incidence of fatal pulmonary embolism after
primary hip and knee replacement in a consecutive series of 4253
patients. J Bone Joint Surg Br. Vol 91‐B, No 5, May 2009. 645‐648.
5. Jameson SS, Baker PN, Charman SC, Deehan DJ, Reed MR et al. The effect
of aspirin and low molecular weight heparin on venous
thromboembolism after knee replacement. A non‐randomised
comparison using National Joint Registry Data. J Bone Joint Surg Br. Vol
94‐B, No 7, July 2012. 914‐918.
6. Wang C.‐J, Wang J.W, Weng L.‐H, Hsu C.‐C, Lo C.‐F. Outcome of calf deepvein
thrombosis after total knee arthroplasty. J Bone Joint Surg Br. Vol 85‐
B, No 6, August 2003. 841‐844.
7. Pearse EO, Caldwell BF, Lockwood RJ, Hollard J. Early mobilisation after
conventional knee replacement may reduce the risk of post‐operative
venous thromboembolism. J Bone Joint Surg Br. Vol 89‐B, No 3, March
2007. 316‐322.
Mr Jai Chitnavis
Consultant Orthopaedic Surgeon,
The Cambridge Knee Clinic.
Honorary Consultant,
Cambridge University Hospitals NHS Trust