Thromboprophylaxis following hip and knee arthroplasty

To determine local thromboprophylaxis prescribing practices following arthroplasty.

A retrospective review was performed of 300 consecutive hip and knee arthroplasty patients (150 each) over a 2-year period at Tasmania's major public hospital. The provision of thromboprophylaxis, the presence of bleeding/thrombotic risk factors and the prevalence of symptomatic venous thromboembolism (VTE) and major bleeding occurring within 90 days postoperatively were documented.

The mean age of the 300 patients (169 females, 131 males) was 68.7 years (standard deviation 10.4). Only 11.3% of knee arthroplasty and 16.7% of hip arthroplasty inpatients had mechanical thromboprophylaxis documented during their stay. All inpatients received pharmacological thromboprophylaxis, predominantly injectable anticoagulants (98.4%). Only 36.5% continued to receive pharmacological thromboprophylaxis following discharge, predominantly an antiplatelet agent (55.5%). The 90-day incidence of symptomatic VTE was 2.7% (95% confidence interval: 1.0-5.0%); 4.0% (95% confidence interval: 1.0-8.0%) for knees and 1.3% (95% confidence interval: 0-5.0%) for hips. The in-hospital and post-discharge VTE incidence was 0.7% and 2.0% respectively. All readmissions for VTE occurred within 1 month of surgery.

While inpatient thromboprophylaxis was routine, it generally was not continued on discharge, potentially leaving many patients exposed to a higher risk of VTE. Most cases of symptomatic VTE occurred after discharge, with the majority requiring readmission to hospital under medical units.Within the limitations of a retrospective study, these findings suggest a need for further research and discussion regarding what constitutes appropriate thromboprophylaxis (type, agent and duration) following hip or knee arthroplasty.