THE TEMPORAL RELATIONSHIP BETWEEN SMOKING CESSATION AND RISK OF PROSTHETIC JOINT INFECTION

Smoking is well-established as an independent risk factor for complications after orthopaedic surgery, particularly heavy smoking (one or more packs/day). Less clear however, is the impact of smoking cessation, specifically the timing of smoking cessation, relative to surgery. We set out to determine if there was a duration of time after cessation of smoking after which the risk for infection after surgery plateaued. Retrospective cohort study utilizing administrative data. We identified adult patients (18 years old of age or older) that received their first total hip (THA) and total knee arthroplasty (TKA) for osteoarthritis between 2010–2020 that also received counselling for smoking cessation up to six years prior to surgery. We then developed a restricted cubic spline to relate the timing of smoking cessation before the joint replacement to the risk for deep prosthetic joint infection (PJI) within one year of surgery, while controlling for patient co-morbidities, socioeconomic status and provider factors (surgeon and hospital volumes). The cohort comprised of 2,050 patients (57% female) of which 43% were THAs and 57% were TKAs. The median time before surgery that patients received their most recent counseling for smoking cessation was approximately 2 years [Interquartile range (IQR): 1.1 – 3.5 years]. 126 patients (6.1%) underwent a revision for infection within one year of surgery. As expected, the restricted cubic spline suggested an inverse relationship between timing of cessation and risk for PJI, with the risk remaining relatively stable for 2 years after cessation before beginning to fall. It may take up to two years following cessation of smoking before the risk of PJI following TJA plateaus. This is an important finding, as it demonstrates that even recent ex-smokers have a substantially increased risk of PJI following TKA. Given that smoking is a modifiable risk factor for PJI, it is important to consider this when consenting and counselling patients for TJA. With the increased use of smoked cannabis products and alternative forms of tobacco smoke (e.g. vapes and e-cigarettes), it is important to better understand the relationships between nicotine (in various forms), tobacco smoke, and other forms of smoking on the risk of PJI and complications following TJA.