Documented Cannabis Use Is a Risk Factor for Nonunion After Nonoperative Management of Scaphoid Fractures: A Retrospective Review of 159 998 Patients.

Background: The purpose of the present study was to assess whether an association exists between cannabis use and nonunion among patients with acute scaphoid fractures initially treated nonoperatively.

Methods: Using the PearlDiver national data set (2010-2020), adult patients with a scaphoid fracture were identified. Patients initially treated with nonoperative management were selected, and 3 subgroups were defined: non-cannabis/non-tobacco (non-users), tobacco-only, cannabis-only. Matched cohorts for each subgroup controlled for age, sex, and comorbidities. Nonunion rates at 6 months, 12 months, and 2 years after fracture diagnosis were determined for each subgroup's matched cohort. Rates of subsequent nonunion surgery were also determined. Multivariable analysis was then done to determine potential associations.

Results: A total of 159 998 scaphoid fracture patients were identified. The non-users' group exhibited a nonunion rate of 7.7%. The nonunion rates for the tobacco-only and cannabis-only groups (11.8% and 10.1% respectively) were significantly greater than that of the non-users group. Based on multivariable analysis, cannabis use and tobacco use were individually associated with a greater risk of scaphoid nonunion as well as subsequent nonunion surgery at 6 months, 12 months, and 2 years after index fracture.

Conclusion: Documented cannabis use in the electronic medical record is associated with an increased risk of scaphoid nonunion and subsequent nonunion surgery. Further studies are necessary to clarify if this association can be contributed solely to cannabis use, to mixing cannabis or tobacco, or to other variables. In the meantime, physicians can counsel their patients on this potential association and increased risk.