D-dimer Levels are not a Good Marker for Venous Thromboembolism in Patients Before and After Total Hip Replacement

Total hip replacement activates the coagulation and fibrinolysis systems. The aim of this paper is to describe the concentrations of these proteins following elective total hip replacement.

This prospective laboratory study enrolled 30 patients (including 18 women) who had been qualified for primary total hip replacement due to idiopathic osteoarthritis. Mean age was 70 years (range: 45-86 years). All patients received venous thromboembolism (VTE) prophylaxis according to the current guidelines (enoxaparin 40 mg SC s.i.d. from the day of the procedure). An immunoenzymatic assay (ACL TOP 500 CTS analyser, Beckman Coulter, Brea, CA, USA) was used to determine D-dimer levels before the surgical procedure, 6 hours after the procedure, and on the 2nd, 4th, and 6th post-operative day.

No patients showed signs and symptoms of VTE during the hospital stay. The mean D-dimer level before the procedure was 1 mg/ml, with a highest mean value of 11.8 mg/ml at 6 hours after the procedure; the levels would then decrease but would remain above the normal range for 6 days after surgery. Elevated baseline D-dimer levels (>0.5 mg/ml) were found in 80% of the study patients.

1. D-dimers act like acute phase proteins, with levels increasing several-fold following total hip repla-cement. 2. D-dimer levels cannot be used to diagnose venous thromboembolism even before the procedure and hospi-talisation in patients with idiopathic coxarthrosis and no clinical manifestations of thrombosis.