Study: Patients using cannabis experience higher rates of scaphoid fracture nonunion

A recent study found that patients who used cannabis, either alone or with tobacco, experienced higher rates of scaphoid fracture nonunion compared to nonusers and tobacco-only users. The findings were presented at the AAOS 2026 Annual Meeting in New Orleans in early March.

“Tobacco use is a well-established risk factor for fracture nonunion, but with increasing legalization, cannabis use has become far more prevalent, and its orthopaedic implications are not well understood,” the study’s lead author Adam Mark Gordon, MD, told AAOS Now. “We wanted to examine whether cannabis exposure, alone or in combination with tobacco, was associated with impaired healing after scaphoid fractures treated nonoperatively.

“Our goal was to determine whether cannabis use represents an independent risk factor for scaphoid nonunion, rather than simply serving as a surrogate for tobacco use or other comorbidities. By separating cannabis-only, tobacco-only, and combined users, we aimed to better reflect real-world patient behavior.”

This retrospective cohort study used patient data from a large national healthcare database spanning from 2010 to 2021. Adult patients with acute scaphoid fractures who were initially managed nonoperatively were identified for inclusion, with a total of 260,806 patients selected for analysis. They were classified into four groups: those who used neither tobacco nor cannabis (165,699 patients), those who used tobacco only (75,504), cannabis only (4,225), and those who used both (15,378). The outcomes were evaluated at six months, 12 months, and 24 months following fracture diagnosis.

Across all time points, patients in the cannabis and combined-use groups had higher rates of nonunion. At 12 months post-fracture, nonunion was observed in 1.9% of nonusers, 3.2% of tobacco-only users, 3.9% of cannabis-only users, and 6.2% of those who used both substances. By 24 months, these rates had increased slightly to 2.0%, 3.6%, 4.3%, and 6.9%, respectively.

“While we expected tobacco use to increase nonunion risk, we were surprised to see that cannabis use alone was also independently associated with higher nonunion rates,” Dr. Gordon said. “The magnitude of risk was greatest when cannabis and tobacco were used together, suggesting a potential synergistic effect.”

In limitations, the authors noted that coding errors in the national databases could contribute to underreporting, which provides a possible explanation for the relatively low nonunion rates previously described. In addition, researchers did not have access to details such as the frequency or method of consumption (e.g., smoking, electric cartridges, or edibles) as well as the relative location of the fracture on the scaphoid (e.g., proximal pole). Finally, the retrospective nature limits the generalizability achievable from prospective studies that could elucidate the causality between cannabis and scaphoid nonunion.

Despite these limitations, the increased likelihood of nonunion following a scaphoid fracture when there is tobacco and/or cannabis use should guide how providers counsel patients who use tobacco or cannabis, as well as the relative risk of nonunion and need for operative intervention.

“This research is significant because scaphoid fractures are common, often treated nonoperatively, and nonunion can lead to long-term wrist dysfunction. Our findings suggest that cannabis use should be considered during risk stratification and counseling, similar to how we currently address tobacco use,” Dr. Gordon said. “As cannabis use becomes more widespread, especially among younger patients who commonly sustain scaphoid fractures, understanding its impact on bone healing is increasingly important. These findings highlight the need for more informed patient counseling and further investigation into the biological mechanisms involved.

Dr. Gordon’s co-authors on “Association Between Cannabis Use and Tobacco Use with Nonunion of Nonoperative Management of Scaphoid Fractures,” are Patrick Nian, BA; Jack Choueka, MD, FAAOS; and Isaac Gammal, MD.

Theresa Witham is managing editor of AAOS Now.