Paul E. Matuszewski MD1, David Zuelzer MD1, and Robert V. O’Toole MD2 1 Department of Orthopaedic and Sports Medicine, University of Kentucky, Lexington, KY, USA 2 University of Maryland, Shock Trauma, Baltimore, MD, USA Despite national public health campaigns, smoking in the United States remains a common and preventable cause of morbidity and mortality. In 2015, 15.1% of all adults (36.5 million people) were current everyday cigarette smokers.1 Smoking is linked to 480 000 deaths per year in the United States (1 in 5 deaths) and 8 million deaths worldwide and has been clearly linked to multiple types of cancer, cardiovascular and respiratory disease, reproductive complications, and multiple other effects. Patients that smoke die on average 10 years earlier than patients that do not smoke.2 Fortunately, this may be reversible. Five to 15 years of smoking abstinence makes the risk of coronary heart disease, stroke, and all‐cause mortality drop to the level of nonsmokers.3 Despite widespread knowledge regarding the general ill effects of smoking on personal health, less is known about smoking with regards to the musculoskeletal system.4 This is concerning, as orthopedic trauma is associated with a much higher rate of smoking than the general public, with some studies quoting as high as 50–60% smokers.5 Smoking carries significant risks for the musculoskeletal system. Tobacco smoke contains approximately 4000 potentially toxic substances. Nicotine is the most frequently cited culprit, although evidence supporting this is contradictory. Basic science research has shown that nicotine has sympathomimetic action, stimulating epinephrine and norepinephrine release, causing vasoconstriction and stimulating platelet adhesion causing micro clot formation and limiting tissue perfusion.6,7 Nicotine also reduces red blood cell, macrophage, and fibroblast proliferation and has been linked to decreased vascular endothelial growth factor, various bone morphogenic proteins, and collagen expression. It has been suggested, based on experimental animal studies, that these combined molecular influences cause nicotine to impair bone healing by inhibiting neovascularization and osteoblast differentiation.8–11 However, other studies have shown that nicotine at lower doses may, in fact, increase osteoblast activity in vitro.12,13 Thus, the negative musculoskeletal effect of nicotine may be dose dependent. To improve patient outcomes in orthopedics, it is critical to understand which reversible factors may predispose to poor outcome. Similarly, in orthopedics, it has been conclusively shown that smoking is associated with worse outcomes. Patients that smoke tend to be younger and have lower comorbidity profiles than nonsmokers.14 However, despite being on average younger and healthier, orthopedic patients that smoke have been found to have longer surgical and anesthesia times, spend more time in the hospital, and have higher average hospital charges compared to nonsmokers. The reason for this discrepancy is difficult to decipher. Patients that smoke may be more likely to have other associated underlying diagnoses that make their care more complex and smoking is more likely in patients with underlying psychiatric illnesses including depression, schizophrenia, and bipolar disorder, which have been linked to poor outcomes.15 Regardless, smoking is now recognized as a moderator for poor outcome. Smoking increases the risk of postoperative complications of any kind as well as deep wound infections.16 Procedures reliant on bony healing or osseointegration may be particularly susceptible. Smokers have increased time to union and nearly twice the risk for nonunion after fracture, spinal fusion, osteotomy, arthrodesis, or nonunion treatment.17 In the arthroplasty literature, smoking has been linked to increased risk of prosthesis‐related complications. A meta‐analysis of 8181 smokers undergoing total hip arthroplasty (THA) found a significantly increased risk of aseptic loosening (risk ratio [RR] = 3.015; 95% confidence interval [CI]: 1.42–6.58), deep infection (RR = 3.71; 95% CI: 1.86–7.41), and all‐cause revision (RR = 2.58; 95% CI: 0.77–2.10).18 A large retrospective cohort study of THA and total knee arthroplasty (TKA) performed at a single institution found significantly higher risk for factors associated with poor outcome including deep infection (hazard ratio [HR] = 2.37; 95% CI: 1.19–4.27) and all‐cause revision (HR = 1.78; 95% CI: 1.01–3.13) in smokers.19 A meta‐analysis reviewed 528 abstracts on foot and ankle surgeries for the effect of tobacco use on an array of foot and ankle procedures. All procedures dependent on bone healing – including joint arthrodesis, fracture fixation, and deformity correction at all levels – were adversely impacted by smoking.20 Smoking negatively impacts both the objective and subjective outcomes of lumbar and cervical spine surgery. Patients that currently smoke at the time of spinal procedure are more likely to experience pseudarthrosis and postoperative infection and report lower subjective outcome scores.21 In the patient who smokes and has a long‐bone fracture there is an increased risk for nonunion (odds ratio [OR] = 2.32; 95% CI: 1.76–3.01; p <0.001) or delayed healing (30.2 weeks [95% CI: 22.7–37.7] for smokers, 24.1 weeks [95% CI: 17.3–30.9] for nonsmokers).22 The Lower Extremity Assessment Project (LEAP) study looked at the impact of current and former smoking on limb‐threatening open tibia fractures. Current smokers were more than twice as likely to develop infection (OR = 2.22; 95% CI: 1.01–4.91; p = 0.05) and almost four times as likely to develop osteomyelitis (OR = 3.72; 95% CI: 1.25–11.1; p = 0.01). Former smokers’ risk for osteomyelitis was lower (OR = 2.80; 95% CI: 0.89–8.83; p = 0.07) than their actively smoking counterparts.23 Smoking has been associated with increased risk for postoperative wound complication and infection across all surgical subspecialties. However, patients that smoke are particularly susceptible to procedures reliant on osseous healing for a good outcome. This includes the osseointegration of the bone–implant interface in arthroplasty and osseous healing necessary in successful joint arthrodesis, osteotomy or deformity correction, and fracture care. Smoking is associated with increased rates of nonunion. In the clinical scenario presented, we described a healthy young patient that smokes at the time of a limb‐threatening open fracture. If she were to stop smoking before her definitive procedure, would that change her expected outcome? The evidence is mixed. Across all surgical specialties there are good data to support that having longer periods of smoking cessation at least four weeks prior to a procedure decreases the incidence of total complications, including postoperative wound healing and pulmonary complications.15
11 Smoking Cessation
Clinical scenario
Introduction
Top three questions
Question 1: In patients undergoing orthopedic procedures, do smokers, compared to nonsmokers, have worse outcomes?
Rationale
Clinical comment
Findings
Resolution of clinical scenario
Question 2: In patients undergoing orthopedic procedures, does smoking cessation, compared to persistent smoking, decrease the likelihood of a poor outcome?
Rationale
Clinical comment
Findings