Thromboprophylaxis following hip and knee arthroplasty

Aim: To determine local thromboprophylaxis prescribing practices following arthroplasty.

Methods: 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.

Results: 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.

Conclusions: 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.