Systemic fat and thrombus embolization in patients undergoing total knee arthroplasty with regional heparinization.

A double-blind, randomized, controlled study was undertaken to determine if a technique of intraoperative anticoagulation would decrease the incidence or severity of venous embolization after tourniquet release during total knee arthroplasty. Sixty-six patients were randomized to receive either the heparin or placebo treatment. Transesophageal echocardiography was performed before and after tourniquet release to detect embolic material in the right atrium. Transient opacification of the right atrium was observed in all patients within the first 30 seconds after tourniquet release. Regional limb heparinization is not effective in reducing the intensity of right atrium opacification because much of the echogenic material was composed of fat rather than thrombus.