The effect of tobacco use on clinical outcomes in total knee arthroplasty patients.

Introduction: Previous research has established that smoking significantly increases the complication rate of total knee arthroplasty (TKA). Risk of infection, prosthetic loosening, fractures, wound healing issues, and revisions are increased in smokers, but research is limited on the long-term clinical outcomes of pain, range of motion, stability, and functionality between smokers, nonsmokers, and former smokers, specifically utilizing Knee Society Scores (KSS).

Methods: This was a retrospective chart review of primary TKA patients (n = 203) at a single university hospital. The patients were divided by smoking status: nonsmoker, current smoker, or former smoker. One-way analysis of variance with associated f ratios was performed to assess variance in KSS by smoking status over time. Relative risk ratio analyses were employed to assess patients' predictive risk of acquiring postoperative infection and requiring additional surgery following TKA based on smoking status.

Results: Postoperative KSS were significantly lower in the smoker group compared to nonsmokers and former smokers at 6 weeks and 1 year. For every 20 months a former smoker used tobacco, an approximate 1-point decrease in KSS was expected. The relative risk ratios for postoperative infection rates and patients requiring additional surgery were 2.13 and 1.44, respectively, when current smokers were compared to nonsmokers.

Conclusions: This analysis found that current smokers had lower KSS and higher infection rates following TKA when compared to nonsmoking controls. In addition, increased duration of smoking was correlated with poorer outcomes within the former smoker group.