Smoking as a Risk Factor for Complications Following Total Joint Arthroplasty

Prior studies evaluating perioperative risk associated with smoking following total joint arthroplasty (TJA) have assessed smoking as a categorical variable. The purpose of this study was to analyze smoking as a risk factor for complications following TJA by assessing pack-year data as a continuous variable. The National Surgical Quality Improvement Program (NSQIP) database was used to identify primary total hip (THA) and total knee arthroplasty (TKA) patients. Propensity scoring was used to match smokers with nonsmokers based on age and sex. Pack-year data were treated as a continuous variable using a smoothing cubic spline analysis to assess risk of wound complications, thrombotic events, 30-day readmission, and total complications. A total of 1044 smokers who underwent a primary TJA were matched to 1044 controls from 143,641 nonsmokers. Smoothing spline analysis did not identify a relationship between increasing pack-years and wound complications, thrombotic events, or total complications. However, the 30-day readmission rate was increased regardless of the pack-year exposure (odds ratio, 2.30; 95% CI, 1.45-3.65; P<.001). This risk persisted after controlling for differences in comorbidities (odds ratio, 2.18; 95% CI, 1.34-3.53; P<.001). Smokers who undergo a TJA procedure have an increased risk of 30-day readmission and wound complications regardless of their pack-year exposure. [Orthopedics. 2021;44(5):e639-e644.].