Cannabis linked to higher surgical and mental health complications after bone surgery

Cannabis use is rapidly increasing in the United States, yet its perioperative implications remain poorly understood, particularly in trauma populations. Despite expanding legalization, the perioperative effects of cannabis on surgical outcomes remain uncertain. This retrospective cohort study used electronic health record data to evaluate the association between cannabis use, with and without concurrent nicotine exposure, and postoperative outcomes following orthopedic lower extremity trauma fixation. We conducted a retrospective cohort study using the TriNetX Research Network, a global federated electronic health record platform that aggregates de-identified clinical data from more than 90 health systems. Adult patients who underwent surgical fixation of lower extremity fractures between 2015 and 2023 were stratified into four cohorts: cannabis only users (n = 2421), nicotine only users (n = 36,966), concurrent users (n = 2338), and non-users. Primary outcomes included surgical and medical postoperative complications; secondary outcomes included psychosocial outcomes and coagulation parameters (PT, aPTT). Binary outcomes were evaluated using absolute risk differences, risk ratios (RR), and 95% confidence intervals (CIs). Continuous variables were compared using independent samples t-tests assuming unequal variances. Cannabis-only users demonstrated higher rates of deep implant infection, nonunion or malunion, reoperation, transfusion, readmission, anxiety, and depression compared with matched non-users. Nicotine-only users showed higher rates of wound complications, infection, nonunion or malunion, reoperation, transfusion, pneumonia, myocardial infarction, death, opioid use, chronic pain, readmission, anxiety, and depression compared with matched non-users. Concurrent cannabis-and-nicotine users had higher rates of superficial wound infection, deep implant infection, reoperation, amputation, transfusion, pneumonia, respiratory failure, opioid use, chronic pain, readmission, and anxiety compared with matched cannabis-only users. Coagulation measures were not consistently different across exposure groups. Cannabis use was associated with surgical and psychosocial complications in this large retrospective cohort. Nicotine use was associated with broader adverse effects, and concurrent cannabis-and-nicotine exposure was associated with compounded perioperative risk. These findings support further prospective evaluation of perioperative substance use screening and counseling strategies in surgical populations. Prospective studies quantifying cannabis exposure are needed to define dose-response effects and mechanisms.