Although early aseptic mechanical failure after total knee
arthroplasty has been reported in younger patients, it is unknown
whether early revision due to periprosthetic joint infection is more or
less frequent in this patient subgroup. The purpose of this study was to
determine whether the incidence of early periprosthetic joint infection
requiring revision knee surgery is significantly different in patients
younger than fifty years of age compared with older patients following
primary unilateral total knee arthroplasty.
Methods:
A large population-based study was conducted with use of the
California Patient Discharge Database, which allows serial linkage of
all discharge data from nonfederal hospitals in the state over time.
Patients undergoing primary unilateral total knee arthroplasty during
2005 to 2009 were identified. Principal outcomes were partial or
complete revision arthroplasty due to periprosthetic joint infection or
due to aseptic mechanical failure within one year. Multivariate analysis
included risk adjustment for important demographic and clinical
variables. The effect of hospital total knee arthroplasty volume on the
outcomes of infection and mechanical failure was analyzed with use of
hierarchical modeling.
Results:
At one year, 983 (0.82%) of 120,538 primary total knee
arthroplasties had undergone revision due to periprosthetic joint
infection and 1385 (1.15%) had undergone revision due to aseptic
mechanical failure. The cumulative incidence in patients younger than
fifty years of age was 1.36% for revision due to periprosthetic joint
infection and 3.49% for revision due to aseptic mechanical failure. In
risk-adjusted models, the risk of periprosthetic joint infection was 1.8
times higher in patients younger than fifty years of age (odds ratio =
1.81, 95% confidence interval = 1.33 to 2.47) compared with patients
sixty-five years of age or older, and the risk of aseptic mechanical
failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval
= 3.77 to 5.76). The rate of revision due to infection at hospitals in
which a mean of more than 200 total knee arthroplasties were performed
per year was lower than the expected (mean) value (p = 0.04).
Conclusions:
Patients younger than fifty years of age had a significantly higher
risk of undergoing revision due to periprosthetic joint infection or to
aseptic mechanical failure at one year after primary total knee
arthroplasty.
