Although a number of agents have been shown to reduce the risk of thromboembolic disease, their use in total hip replacement (THR) remains controversial. Uncertainty exists regarding the safety of chemical prophylaxis as well as the choice of the most effective agent. Previous studies suggested that pneumatic compression with foot-pumps provide the best balance of safety and effectiveness, however too few patients were investigated in randomised clinical trials to draw evidence-based conclusions.

The purpose of this randomized clinical trial was to compare the safety and efficacy of pneumatic compression with foot-pumps versus low-molecular-weight heparin (LMWH) for prophylaxis against DVT.

Inclusion criteria were hip osteoarthritis and age less than 80 years. Exclusion criteria were history of thromboembolic disease, heart disease, and bleeding diatheses. 216 consecutive patients were considered for inclusion in the trial and were randomized either for management with LMWH (Fraxiparin, Sanofi-Synthelabo, France) or with the A-V Impulse foot-pump (Orthofix Vascular Novamedix, UK). Patients were monitored for DVT using serial duplex sonography and phlebography.

DVT was detected in 3 of 100 patients managed with the foot-pump compared with 6 of 100 patients who received chemical prophylaxis (p< .05). Sixteen patients did not tolerate continuous use of the foot-pump and were excluded from the study. The average postoperative drainage was 259ml in the foot-pump group and 328ml in the LMWH group (p< .05). Patients with foot-pump had less swelling of the thigh (10mm compared with 15mm) (p< .05). The patients of the foot-pump group had less postoperative oozing and bruising than did those who had received LMWH. One patient developed heparin-induced thrombocytopenia.

This study confirms the safety and efficacy of mechanical prophylaxis of DVT in THR. Some patients cannot tolerate the foot-pump.

Introduction Venous thromboembolic disease is a serious complication of total hip replacement (THR). Use of low-molecular-weight heparin (LMWH) has been shown to reduce the occurrence of deep-vein thrombosis (DVT) significantly, but side effects such as bleeding and thrombocytopenia are frequent. Pneumatic compression with foot-pumps seems to provide the best balance of effectiveness and safety. However, a recent meta-analysis showed that the overall number of patients investigated in randomised clinical trials is too small to draw evidence-based conclusions regarding mechanical prophylaxis of DVT. This trial is a contribution in comparing the effectiveness and safety of mechanical versus chemical prophylaxis of DVT in patients managed with THR.

Methods Inclusion criteria were hip osteoarthritis, age less than 80 years, and uninterrupted use of a foot-pump. Exclusion criteria were a history of thromboembolic disease, heart disease, malignancy and bleeding diatheses. Two hundred and sixteen consecutive patients were considered for inclusion in the trial and were randomized either for management with (LMWH) (Fraxiparin, Sanofi -Synthelabo, France) or with the A-V Impulse foot-pump (Orthofix Vascular Novamedix, UK). All patients started mobilisation on crutches with partial weight-bearing on day two using compression stockings. The foot-pump was applied on both feet in the recovery room and was used until patient discharge. Management with the foot-pump was interrupted only during physiotherapy and toileting. A reverse Trendelenburg position (head-high, feet-low) was applied at rest to enhance the pneumatic effect of the pumps. Patients were monitored for DVT using serial duplex sonography (Sonoline Elegra, Siemens, Germany) at day three, 10 and 45 after surgery.

Results DVT was detected in three of 100 patients managed with the foot-pump compared with six of 100 patients who received chemical prophylaxis. Sixteen patients did not tolerate continuous use of the foot-pump and were excluded from the study. The average post-operative drainage was 259 ml in the foot-pump group and 328 ml in the control group (p=0.05). Patients with foot-pump had less swelling of the thigh (10 mm compared with 15 mm) (p=0.05). One patient developed heparin-induced thrombocytopenia.

Conclusions This study confirms the effectiveness and safety of mechanical prophylaxis of DVT in THR, confirming the outcomes of previous randomized clinical trials. Some patients cannot tolerate the foot-pump, mostly because of sleep disturbance.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.