Venous thromboembolism after lower limb arthroplasty: is chemical prophylaxis still needed?

Venous thromboembolism (VTE) is a significant complication of lower limb arthroplasty. The National Institute for Health and Care Excellence recommends routine use of chemical and mechanical prophylaxis to prevent VTE. Our high-volume, elective, arthroplasty unit adopted this guidance in 2008.

We examined our incidence of VTE before and after introduction of chemical thromboprophylaxis to determine whether the incidence of VTE reduced.

We retrospectively gathered data on 2 cohorts of patients-from January 2004 to August 2007 (Group 1) and January 2010 to December 2012 (Group 2). Patients in Group 1 received mechanical prophylaxis only (unless particularly high risk for VTE), and patients in Group 2 received mechanical and chemical prophylaxis. We recorded VTE occurring within 6 months of surgery. Patients in Group 1 receiving chemical prophylaxis were excluded.

Group 1 had 2320 cases of primary and revision lower limb arthroplasty, and Group 2 had 1430 cases. VTE occurred in 37 cases in Group 1 (1.6 %), and in 17 cases in Group 2 (1.2 %). This difference was not statistically significant (p = 0.26). In Group 1, 1 patient died within 6 months due to pulmonary embolism (0.04 %); there were no VTE-related deaths in Group 2 (0 %). This was also not statistically significant (p = 0.06).

Although our VTE rate reduced by 0.4 % and our VTE-related mortality reduced by 0.04 % after introduction of chemical thromboprophylaxis, these differences were not statistically significant. Chemical thromboprophylaxis may not be required in all patients undergoing arthroplasty providing appropriate mechanical prophylaxis is used.