Age alone is not a risk factor for periprosthetic joint infection

It is not known whether age alone or the increased comorbidities in older patients are responsible for the higher rate of periprosthetic joint infection (PJI) in older patients.

To test the hypothesis that age alone is not a risk factor for PJI after total joint arthroplasty.

This retrospective study included the review of 23,966 patients undergoing primary total hip and knee arthroplasty between January 1^st, 2010 and December 31^st, 2016 at a single institution. Patients who developed PJI, as defined by International Consensus Meeting criteria, were identified. All enrolled patients were divided into three groups that included patients aged <65 years (N = 12,761), 65-74 years (N = 6850) and ≥75 years (N = 4355). Using multivariate analysis and propensity score matching analysis, the possible association between age and PJI was examined.

The incidence of PJI in the entire cohort was 0.72% (171 out of 23,966). Multivariate analysis adjusting for all variables, except age, demonstrated that, compared to the patients aged <65 years, there was no statistically significant difference in the rate of PJI for patients aged 65-74 years (odds ratio: 0.89; 95% confidence interval: 0.55-1.42; P = 0.62) or for patients aged ≥75 years (0.69; 0.36-1.32; P = 0.26).

When adjusting for confounding variables, age alone is not a risk factor for PJI. Studies evaluating the influence of age on the incidence of PJI should take into account the other confounding variables that contribute to PJI.