The aim of the study is to analyze the effect of smoking and smoking cessation on the incidence of complications among orthopedic and hand surgery patients, and to determine the feasibility of smoking cessation intervention, as well as factors predicting success in smoking cessation. Orthopedic and hand surgery patients will be invited to participate in the study, which will recruit 550 participants (at least 20% daily smokers). A participant will be defined as a daily smoker if he/she reports daily smoking and/or laboratory tests show active smoking. Data will be collected using a self-reported questionnaire and from medical records. Smokers will receive information about the benefits of smoking cessation and will be encouraged to quit. Medication or nicotine replacement therapy will be prescribed. Laboratory tests will be taken two weeks before and two weeks after surgery. Follow-up phone calls will be made at 3, 6, and 12 months after surgery. The primary outcome is any complication, defined as a prolonged stay in hospital or any additional visit to or measure taken by a health service during the 12 months after surgery. Data on complications are mainly obtained from personal health records and from the information received at the follow-up; the rest of the data will be collected from the register of healthcare-associated infections. Secondary outcomes are the number and types of complications. The sample (n=550) was calculated to observe a 10% difference in complications between smokers and non-smokers (5% alpha level and 80% power), considering a 10% drop-out rate. Logistic regression and log-linear models will be used for data analyses.