We examined the one-year risk of symptomatic
venous thromboembolism (VTE) following primary total hip replacement
(THR) among Danish patients and a comparison cohort from the general
population. From the Danish Hip Arthroplasty Registry we identified
all primary THRs performed in Denmark between 1995 and 2010 (n =
85 965). In all, 97% of patients undergoing THR received low-molecular-weight
heparin products during hospitalisation. Through the Danish Civil
Registration System we sampled a comparison cohort who had not undergone
THR from the general population (n = 257 895). Among the patients
undergoing THR, the risk of symptomatic VTE was 0.79% between 0
and 90 days after surgery and 0.29% between 91 and 365 days after
surgery. In the comparison cohort the corresponding risks were 0.05%
and 0.12%, respectively. The adjusted relative risks of symptomatic
VTE among patients undergoing THR were 15.84 (95% confidence interval
(CI) 13.12 to 19.12) during the first 90 days after surgery and
2.41 (95% CI 2.04 to 2.85) during 91 to 365 days after surgery,
compared with the comparison cohort. The relative risk of VTE was
elevated irrespective of the gender, age and level of comorbidity
at the time of THR. We concluded that THR was associated with an increased risk of
symptomatic VTE up to one year after surgery compared with the general
population, although the absolute risk is small.