Cannabis and nicotine use are independently associated with adverse surgical, medical, and psychosocial outcomes following upper extremity fracture fixation

BACKGROUND: Marijuana use is rising in the United States, yet its impact on perioperative outcomes remains poorly understood, particularly in orthopaedic trauma where cessation is often not feasible. This study evaluates the risks associated with cannabis and nicotine use in patients undergoing fixation of upper extremity fractures. METHODS: We performed a retrospective analysis of adult trauma patients with upper extremity fractures (2015-2023) identified using CPT codes for surgical fixation in the TriNetX database. Four cohorts were defined: cannabis-only users (n = 801), nicotine-only users (n = 14,310), concurrent users (n = 901), and non-users matched 1:1 to each exposure cohort. Propensity score matching was applied to each pairwise comparison. Primary outcomes were surgical and medical complications; secondary outcomes included new postoperative psychosocial diagnoses (anxiety, depression, opioid use disorder, and chronic pain) and coagulation parameters. Binary outcomes were compared using absolute risk differences, risk ratios, odds ratios, and 95% confidence intervals; continuous outcomes with independent t-tests, all assessed within 1 year following surgery. RESULTS: Cannabis-only users had significantly higher rates of implant-related infection, reoperation, readmission, depression, and anxiety compared with non-users (p < 0.05). Nicotine-only users demonstrated higher odds ratios in most overlapping outcomes and showed significantly elevated rates across a broader range of complications, including superficial and deep infection, nonunion or malunion, wound dehiscence, pneumonia, chronic pain, mortality, and psychosocial complications. Concurrent users did not demonstrate additive risk compared with cannabis-only users. CONCLUSION: Cannabis and nicotine use were independently associated with increased postoperative complications following fixation of upper extremity fractures compared with matched non-user controls. The absence of statistically significant additive effects may reflect limited power to detect modest interactions, overlapping biological mechanisms, or a true absence of synergy. These findings support standardized screening, risk stratification, and targeted perioperative strategies, including extended antibiotic prophylaxis and integrated psychosocial support, to reduce complications in this at-risk population.