Meta-analysis of thromboembolic prophylaxis after total knee arthroplasty

We performed a meta-analysis of the English literature to assess the effica cy of four common regimes for thromboembolic prophylaxis after total knee a rthroplasty: aspirin, warfarin, low-molecular-weight heparin (LMWH) and pne umatic compression. We reviewed 136 articles and abstracts published betwee n January 1980 and December 1997, Papers not using routine venography and a lung scan or angiography to detect deep-venous thrombosis (DVT) and pulmon ary emboli (PE) respectively, were excluded. Of the 136 studies, 23 with 60 01 patients were selected. The incidence of DVT was 53% (1701/3214) in the aspirin group, 45% (541/1203) in the warfarin group, 29% (311/1075) in the LMWH group, and 17% (86/509) in the pneumatic compression device group. Int ermittent 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 (222/1901), 8.2% (101/1229) in the warfarin group and 6.3% (24/378) in the pneumatic c ompression group. No studies with LMWH used routine lung scans. Warfarin an d pneumatic compression were significantly better than aspirin in preventin g asymptomatic PE (p < 0.05), The incidence of symptomatic PE was 1.3% (23/1800) in the aspirin group, 0. 4% (21559) in the warfarin group, 0.5% (2/416) in the LMWH group and 0% (0/ 177) in the pneumatic compression group. No statistically significant diffe rence was noted between the above prophylatic regimes due to the very small incidence of symptomatic PE, Prophylaxis for thromboembolic disease in TKA may have to include a combina tion of some of the above regimes to incorporate their advantages.