The Impact of Smoking on the Frequency of Intraoperative and Postoperative Complications in Orthopaedic Surgical Patients

BACKGROUND The success of orthopaedic surgery is fundamentally biological, yet the synergistic effect of smoking and comorbidities on surgical outcomes is not well quantified. We hypothesised that active smoking multiplies the risk conferred by common comorbidities. METHODS In this retrospective cohort study, we analysed 3,123 orthopaedic procedures from 2020–2024. Patients were stratified by comorbidity (diabetes, anemia, hepatic dysfunction, chronic venous disease) and smoking status. Primary outcomes were a complex of orthopaedic-specific complications. We used multivariate logistic regression to calculate adjusted odds ratios (aORs) and formal tests for interac-tion to quantify synergy. RESULTS A powerful synergistic effect was observed. Diabetic smokers had significantly higher rates of non-union (9.2% vs 3.3%; aOR 3.0), periprosthetic joint infection (8.2% vs 2.8%; aOR 3.1), and revision surgery (12.2% vs 5.0%; aOR 2.7). Significant interaction effects confirmed this synergy. Smokers with hepatic dysfunction had higher haematoma rates, while smoking with severe anemia was associated with dramatically increased mortality (5.0%; aOR 8.9). Former smokers' outcomes were consistently intermediate. CONCLUSIONS Smoking multiplies comorbidity risk, creating a distinct high-risk phenotype that severely compromises healing. These findings mandate that verified smoking cessation is a non-negotiable, foundational component of preoperative optimisation before elective orthopaedic surgery.