Abstract
Background
Smoking has been associated with poor tissue oxygenation and vascularisation, predisposing smokers to a higher risk for postsurgical infections. The aim of this study was to estimate and compare the incidence of prosthetic joint infection (PJI) following primary total joint arthroplasty (TJA) according to smoking status.
Methods
A prospective hospital-registry based cohort was used including all primary total knee and hip arthroplasties performed between 03/1996 and 12/2013 and following them until 06/2014. Smoking status at time of surgery was classified in never, former and current smoker. Incidence rates and incidence rate ratios (IRR) for PJI according to smoking status were assessed within the first year and over the whole study period. Adjusted IRRs were obtained using cox regression model. Adjustment was performed for the following baseline characteristics: age, sex, BMI, ASA score, diabetes, arthroplasty site (knee or hip) and surgery duration.
Results
We included 8,559 TJAs, 3,361 knee and 5,198 hip arthroplasties. Mean age was 70 years, 61% were women, mean follow-up time was 77 months. 5,722 were never (group 1), 1,315 former (group 2) and 1,522 current (group 3) smokers. Over the study period, 108 PJI occurred. Incidence rates of infection within one year were for group 1, 2 and 3, respectively: 4.7, 10.1 and 10.9 cases/1000 person-year. Comparing ever- vs. never-smokers, the adjusted IRR was 1.84 (95% CI 1.05–3.2). Incidence rates for infection over the whole study period were 1.5, 3.1 and 2.7 cases/1000 person-years for group 1, 2 and 3, respectively. Adjusted IRR for ever- vs. never-smokers was 1.46 (95% CI 0.97–2.19).
Conclusions
Smoking was associated with an about 1.5 times higher incidence rate of PJI following TJA. The difference was established already in the first year after surgery and remained thereafter.
Level of Evidence
prospective registry based comparative cohort study (level II).
