Prevention of venous thromboembolism after knee arthroscopy : six years experience with the low molecular weight nadroparin calcium

Aim. Knee arthroscopy is the most common orthopedic procedure, but few data are available on the epidemiology of venous thromboembolism (VTE) after this kind of surgery. From this point of view, knee arthroscopy is considered a low-risk intervention, and clear indications for antithrombotic prophylaxis in this setting are lacking. Methods. From January 2000 to December 2006 we prospectively evaluated 1 800 patients undergoing knee arthroscopy, and considered at particularly low risk of VTE (no concomitant known risk factors, tourniquet time less than 30 min). These patients received weight-adjusted low molecular weight heparin (nadroparin calcium, 2 850 to 5 700 IU, one subcutaneous injection per day starting 6 hours after arthroscopy) for two weeks. Patients were followed-up for two weeks for the occurrence of symptomatic, instrumentally confirmed VTE, and/or bleeding episodes. Results. Seven cases of distal deep vein thrombosis were documented (overall incidence of VTE was 0.38%). The most frequent registered adverse events were mild hemarthrosis and reactions at injection site; no cases of major bleeding occurred. Conclusion. In this large cohort of low-risk patients, VTE appears as a possible complication of knee arthroscopy, though at an extent probably lowered by the systematic use of antithrombotic prophylaxis. The present study seems to support the feasibility of pharmacological antithrombotic prophylaxis in these patients, with encouraging indications as for benefit/risk ratio. Our experience might stimulate further efforts to better assess and face this open medical issue.