Weeding Out the Problem: Associations of Cannabis and Tobacco Use with Complications of Surgical Fixation of Metacarpal Fracture.

Background: Given the increasing prevalence of cannabis use, it is critical to understand its association with postoperative complications. We investigated association between cannabis use and complications after metacarpal fracture fixation. Methods: We identified 80,787 patients from a US insurance claims database who underwent metacarpal fracture fixation from 2010 to 2022; 5,043 (6.7%) had diagnosed cannabis use disorder, dependence or addiction. Cannabis users were compared with patients with history of tobacco use and those with no history of using either substance ('control group'). Propensity matching was used to control for age, sex and Charlson Comorbidity Index (CCI) value. Demographic and comorbidity profiles, 90-day medical complications and 6-month surgical complications were compared using chi-squared tests (α = 0.05). Results: Compared with the control group, cannabis users had a higher incidence of acute kidney injury, cardiac arrest, deep venous thrombosis, hypoglycemia, myocardial infarction, pneumonia, sepsis, stroke and urinary tract infection (all, p < 0.01) within 90 days after surgery. After matching the cannabis and control groups, the cannabis group had a higher incidence of nerve injury (p < 0.01), fracture nonunion (p = 0.04) and fracture malunion (p = 0.002). Compared with tobacco users, cannabis users had a lower incidence of pneumonia (p = 0.002), urinary tract infection (p < 0.01) and hypoglycemia (p = 0.03) within 90 days. Conclusions: Compared with patients who had no history of drug use, cannabis users had a higher incidence of several medical and surgical complications. Compared with tobacco users, cannabis users had a lower incidence of some medical complications. These differences underscore the need for tailored perioperative care strategies for cannabis users. Level of Evidence: Level III (Therapeutic).