Is Insurance Status a Predictor for the Development of Nonunion Following Scaphoid Fracture?

Introduction: Scaphoid nonunion is a common precursor to radiocarpal arthrosis. Several factors have been associated with development of scaphoid nonunion, including delayed diagnosis, inadequate initial management, proximal location, and carpal instability. We hypothesized that insurance status would also be a risk factor for development of scaphoid nonunion.

Methods: A case-control study was performed on patients who presented to a single surgeon at a tertiary referral center during the period 2006–2015. Cases were defined as patients presenting with nonunions. Controls were defined as patients presenting with primary fractures. Insurance status was characterized as underinsured if the patient lacked any type of insurance or if the patient was on Medicaid. Case/control status was tested for association with patient and fracture characteristics, including age, sex, fracture displacement, fracture location, laterality of fracture, and insurance status.

Results: A total of 71 patients were identified. Of these, 39 (55%) were nonunions (cases) and 32 (45%) were primary fractures (controls). Cases were more likely than controls to have had displaced fractures (72% versus 41%, p = 0.008; Table 1). Cases were also more likely than controls to have fractures located at the proximal aspect (18% versus 0%) and less likely than controls to have fractures located at the distal aspect (0% versus 19%; p < 0.001). Finally, cases were more likely than controls to be underinsured (46% versus 19%, odds ratio = 3.7, 95% confidence interval = 1.3–11.0, p = 0.015, Fig. 1).

Conclusion: Patients presenting with nonunions were more likely than patients presenting with primary fractures to be underinsured. This finding suggests that underinsurance is a risk factor for development of nonunion. Given that delay between fracture and intervention is a known risk factor for development of nonunion, it is likely that the association between nonunion and underinsurance is mediated through this delay. Increased attention should be turned to timely and standard-of-care management of primary fractures in those who lack adequate insurance.