[Detection of deep vein thrombosis of the limbs by ultrasound in orthopedic and traumatologic surgery. Results of 1647 studied patients].

INTRODUCTION

This study was undertaken to estimate the efficiency of duplex ultrasound scanning and its utility to detect deep vein thrombosis in orthopedic patients and to describe their features.

MATERIAL AND METHODS

A total of 1647 in-patients, all receiving low-molecular-weight heparin, were investigated from 1989 to 1993, either for screening because of a high risk of thrombosis (asymptomatic group: 930 patients, mean age + SD: 63 + 17 years) or for clinical suspicion of deep vein thrombosis (symptomatic group: 717 patients, mean age + SD: 57 + 21 years). Difference between the two groups mean ages was significant (p < 10(-8)). An Hitachi EUB 450 duplex and an Acuson colour duplex 128 XP, with 3.5 MHz and 7.5 MHz linear probes were used. Veins were tested for compressibility in the transverse view from caval site to both ankles. Retrospective analysis of patients' database results was done.

RESULTS

There was no significant difference in deep vein thrombosis rate between screening asymptomatic group (356/930: 38 per cent) and symptomatic group (2531717: 35 per cent). There was a linear relation, in the 2 groups, between age and deep vein thrombosis rate, from 10 per cent before twenty to 45 per cent after eighty years old. For a relative risk to have thrombosis detected before twenty definite at 1, it was 2.1 for 20-29, 4.9 for 40-49, 6.2 for 60-69 and 8.6 later than 80 years old. Proximal deep vein thrombosis was detected in only 5 per cent (87/1647) of patients. Distal muscular soleal veins were the most usual involved sites of thrombosis. Isolated soleal thrombosis were detected in 16 per cent (270/1647) of patients. There was no significant difference between the deep vein thrombosis rate after total knee or hip arthroplasty among selected patients for duplex scanning from 1989, and the true prevalence assessed among all the patients who have undergone total hip or knee arthroplasty during the last 6 months.

DISCUSSION

Pessimistic results previously reported for duplex screening among asymptomatic patients are not confirmed. Calf vein thrombosis rate assessed with duplex exceeds by 15 to 20 per cent the rates assessed by contrast venography, among patients receiving low molecular weight heparins. That difference could be attributed to the isolated muscular soleal thrombosis usually missed at contrast venography.

CONCLUSION

Deep vein thrombosis rate among orthopedic surgical patients, is much higher when detected with Duplex ultrasound scanning than detected with contrast venography, and is related to patient age. Soleal vein thrombosis is the most prevalent. Duplex ultrasound scanning is an efficient and useful screening method for deep vein thrombosis in orthopedic surgery. Mechanical calf venous pump stimulation in association with low molecular weight heparin, has to be evaluated in attempting to reduce those muscular soleal veins thrombosis.