Abstract
Introduction
Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower limb arthroplasty. Trials supporting its use have not fully evaluated the risks of wound complications related to rivaroxaban.
Method
A retrospective cohort analysis of 1558 consecutive patients who underwent total hip or knee replacements within the same hospital during a 19 month period (2009–2010) was performed. The first 489 patients (Group 1) were given tinzaparin postoperatively as per NICE guidance. The following 559 patients (Group 2) were given rivaroxaban. Concerns regarding wound complications prompted a change back to tinzaparin for the next 510 patients (Group 3.) Other than the thromboprophylactic agent used there were no other differences in the pre and postoperative treatments of all these patients.
Results
Nine of the 489 patients in Group 1 (tinzaparin) (1.8%, 95% CI 0.9–3.5%) returned to theatre with wound complications within 30 days compared with 22 out of 559 patients in Group 2 (rivaroxaban) (3.94%, 95% CI 2.6–5.9%.) This increase in RTT rate was statistically significant (p=0.046.) After reverting back to tinzaparin 8 out of 510 patients in Group 3 (tinzaparin) (1.6% 95% CI 0.74–3.1%) returned to theatre. This reduction in RTT rate was statistically significant (p=0.02.) Combining the tinzaparin groups (1 and 3) and comparing with the rivaroxaban group (2) further increases the significance of our observations. Tinzaparin RTT was 1.7% (95% CI 1.0–2.7%) compared with rivaroxaban RTT of 3.94% (95% CI 2.6–5.9%) (p=0.01.)
Discussion
We observed a significant rise in wound complication necessitating further surgery after a change in thromboprophylactic agent from tinzaparin to rivaroxaban, followed by a significant reduction after reverting back to tinzaparin. We call for further independent randomised controlled clinical trials examining wound related complications with respect to new pharmacological treatments.
