Westrich GH, Haas SB, Mosca P, Peterson M.
Meta-analysis of thromboembolic prophylaxis after total knee arthroplasty.
J Bone Joint Surg Br 2000 Aug;82(6):795-800

Hospital for Special Surgery, Cornell University Medical Centre, New York, NY 10021, USA.

We performed a meta-analysis of the English literature to assess the efficacy of
four common regimes for thromboembolic prophylaxis after total knee arthroplasty:
aspirin, warfarin, low-molecular-weight heparin (LMWH) and pneumatic compression.
We reviewed 136 articles and abstracts published between January 1980 and
December 1997. Papers not using routine venography and a lung scan or angiography
to detect deep-venous thrombosis (DVT) and pulmonary emboli (PE) respectively,
were excluded. Of the 136 studies, 23 with 6,001 patients were selected. The
incidence of DVT was 53% (1,701/3,214) in the aspirin group, 45% (541/1,203) in
the warfarin group, 29% (311/1,075) in the LMWH group, and 17% (86/509) in the
pneumatic compression device group. Intermittent pneumatic compression devices
and LMWH were significantly better than warfarin (p < 0.0001) or aspirin (p <
0.0001) in preventing DVT. The incidence of asymptomatic PE was 11.7% in the
aspirin group (222/1,901), 8.2% (101/1,229) in the warfarin group and 6.3%
(24/378) in the pneumatic compression group. No studies with LMWH used routine
lung scans. Warfarin and pneumatic compression were significantly better than
aspirin in preventing asymptomatic PE (p < 0.05). The incidence of symptomatic PE
was 1.3% (23/1,800) in the aspirin group, 0.4% (2/559) in the warfarin group,
0.5% (2/416) in the LMWH group and 0% (0/177) in the pneumatic compression group.
No statistically significant difference was noted between the above prophylactic
regimes due to the very small incidence of symptomatic PE. Prophylaxis for
thromboembolic disease in TKA may have to include a combination of some of the
above regimes to incorporate their advantages.