[Heparin-induced thrombocytopenia as a complication of postoperative prevention of thromboembolism with unfractionated heparin/low molecular weight heparin after hip and knee prosthesis implantation].

AIM

With this prospective study we analysed the occurrence of a heparin-induced thrombocytopenia type II (hit type II) using unfractioned heparin (UFH) or low-molecular-weight heparin (LMWH) as postoperative thrombosis prophylaxis after primary total hip or knee replacements. Furthermore the postoperative course of the platelet count with UFH and LMWH was investigated.

MATERIAL AND METHODS

In a prospective study we looked at the platelet count of 504 primary endoprothesis patients until the 9. postoperative day. 252 patients got UFH (3-mal 5000 IE Liquemin), 252 patients got LMWH (Clexane 40 opd) as thrombosis prophylaxis.

RESULTS

5 patients of the UFH-group developed a HIT type II (incidence 2%; 95%-confidence interval 0.7-4.5) after 9.8 (7-16) days. Within the LMWH-group we saw just one case (incidence 0.4%; 95%-confidence interval 0-2.1). The drop of the platelet count was on average 64% (40.9-81.6). Within the 498 patients without a HIT type II just 2 patients had a drop of the platelet count between the 5. and 9. postoperative day of more than 15% referring to the preoperative value (24% and 33%).

CONCLUSION

The incidence of a HIT type II after the use LMWH seems to be lesser than after the use of UFH. The postoperative platelet count shows a typical course after a total joint replacement. With deviations of that a HIT type II must be excluded.