Practice Therapeutics

New oral anticoagulants for thromboprophylaxis in patients having hip or knee arthroplasty

BMJ 2011; 342 doi: (Published 18 January 2011) Cite this as: BMJ 2011;342:c7270

Prophylaxis for VTE

Prophylaxis for deep vein thrombosis (DVT) and pulmonary embolism
(PE) in patients undergoing major joint replacement surgery generates a
lot of controversy amongst clinicians.

So why is there still controversy? The rate of PE following hip and
knee replacements is currently between 0.2-0.4%. This has been stable over
the last ten years despite the introduction of new drugs(1,2).
Haematologists and thrombosis research scientists such as the authors of
the current review article aim to prevent all DVTs. Orthopaedic surgeons
need to balance between bleeding related risks and medical adverse
effects, on one hand, and the effectiveness in preventing PEs, on the
other. Drug companies aim to recover their investments into the
development of new oral anticoagulants. Regulators such as NICE, SIGN,
AAOS, ACCP want to enforce their guidelines.

Guidelines developed by the American College of Chest Physicians ACCP
faced strong criticism from the American Academy of Orthopaedic Surgeons
(3). The ACCP recommendations are entirely based on the reduction of
venographic evidence of DVT. There is good evidence that there is no link
between VTE and PE in elective orthopaedic surgery. Allegedly, some of the
ACCP members were Consultants for the pharmaceutical industry. The authors
of the current article are Consultants for multinational drug companies as
stated in their disclosure. Although both SIGN and NICE had orthopaedic
representatives, their views were often not taken on board and now their
seems to be even more controversy amongst surgeons, physicians, regulators
and the industry.

The optimal prophylactic regimen for a particular patient should
reflect a clinical judgment regarding the relative risks of both major
bleeding and symptomatic PE. A multimodal approach to the prevention of
DVT and PE seems to be the most sensible one.
The Golden Jubilee National Hospital in Glasgow has been using a
multimodal approach incorporating enhanced recovery, chemical prophylaxis
with Aspirin (for the majority of patients) and mechanical prophylaxis for
over three years now. Over four thousand hip and knee replacements have
been performed with this protocol. The latest annual report from the
Scottish Arthroplasty Project provides evidence in support of our
protocol. The GJNH has one of the lowest DVT and PE rates in Scotland (4).

However, the latest SIGN and NICE guidelines do not recommend Aspirin
despite some good quality research articles (5-8). Many orthopaedic
surgeons in the UK are concerned with the new guidelines from SIGN and
NICE for similar reasons as quoted by their US colleagues (9).
What is the legal situation if we do not follow national guidelines? A
recent review in the legal literature states that there is danger in
applying the generalised prescription of guidelines in a rigid fashion to
every patient. Evidence based medicine cannot fully capture the art of
medical practice and there remains a need for clinical judgment and
discretion. Additionally, guidelines are only as good as the underlying
empirical evidence. The validity may be undermined by weak research data
as well as confounding factors and biases emanating from misconceptions,
personal experience and beliefs of the developers (10).

1. Howie C, et al: VTE associated with hip and knee replacement over
a ten year period. JBJS Br 2005;87:1675-80

2. SooHoo, et al: Factors predicting complication rates following total
knee arthroplasty. JBJS Am 2006;88:480-5

3. Lotke P, et al: J Arthroplasty 2005;20:273-4


5. Lachiewicz, et al: Mechanical calf compression and aspirin prophylaxis
for total knee arthroplasty. CORR 2007;464:61

6. Cusick L, et al: The incidence of fatal PE after primary hip and knee
replacement in 4253 patients. JBJS Br 2009;91:645-648

7. Brown G: VTE after major orthopaedic surgery: a pooled analysis of
RCTs. J Arthroplasty 2009;24:77-83

8. Bozic K, et al: Does Aspirin have a role in VTE prophylaxis in total
knee arthroplasty patients? J Arthroplasty 2010;25:1053-60

9. Treasure T, et al: Developing guidelines for VTE for NICE. JBJS Br

10. Samanta A, Medical Law Review 2006; 321-366

Competing interests: No competing interests

25 January 2011
Alexander W Siegmeth
Consultant Orthopaedic Surgeon
Golden Jubilee National Hospital, Glasgow, UK