Tobacco Use Is Associated with More Severe Adverse Outcomes Than Morbid Obesity after Aseptic Revision TKA

The association of morbid obesity with increased revision total knee arthroplasty (rTKA) complications is potentially confounded by concurrent risk factors. This study was performed to evaluate whether morbid obesity was more strongly associated with adverse aseptic rTKA outcomes than diabetes or tobacco use history-when present as a solitary major risk factor. Demographic characteristics, surgical indications, and adverse outcomes (reoperation, revision, infection, and amputation) were compared between 270 index aseptic rTKA performed for patients with morbid obesity (n = 73), diabetes (n = 72), or tobacco use (n = 125) and 239 "healthy" controls without these risk factors at a mean 75.7 (range: 24-111) months. There was no difference in 2-year reoperation rate (17.8 vs. 17.6%, p = 1.0) or component revision rate (8.2 vs. 8.4%) between morbidly obese and healthy patients. However, higher reoperation rates were noted in patients with diabetes (p = 0.02) and tobacco use history (p < 0.01), including higher infection (p < 0.05) and above knee amputation (p < 0.01) rates in patients with tobacco use history. Multivariate analysis retained an independent association between smoking history and amputation risk (odds ratio: 7.4, 95% confidence interval: 1.7-55.2, p < 0.01). Morbid obesity was not associated with an increased risk of reoperation or component revision compared with healthy patients undergoing aseptic revision. Tobacco use was associated with increased reoperation and above knee amputation. Additional study will be beneficial to determine whether risk reduction efforts are effective in mitigating postoperative complication risks.