Incidence and Factors Associated with Nonunion Following Naviculocuneiform Joint Arthrodesis

Category: Midfoot/Forefoot; Other Introduction/Purpose: Naviculocuneiform (NC) joint arthrodesis is indicated when conservative treatments fail to alleviate painful arthritis or for deformity correction involving the medial column of the foot. While nonunion is a well-recognized complication following NC joint arthrodesis, most studies reporting nonunion rates involve a limited number of cases or focus solely on specific underlying disease entities. Moreover, variations exist between studies in the number of articular facets included in the arthrodesis construct and the type of fixation used, with no clear evidence on how these factors influence success of the procedure. This study aims to investigate the nonunion rate following NC joint arthrodesis and to identify demographic and surgical factors associated with nonunion using the largest reported cohort to date. Methods: One hundred one feet in 93 patients who underwent NC joint arthrodesis between 2016 and 2023 at a single institution were retrospectively identified. Indications for surgery included osteoarthritis (n=80), deformity (n=10, flatfoot or cavus), and rheumatoid arthritis (n=11). Patients with Charcot arthropathy were excluded. Nonunion was defined as a failure to demonstrate radiographic evidence of fusion at the arthrodesis site more than six months after surgery. Nonunions were further categorized into symptomatic and asymptomatic, with symptomatic nonunions being defined as patients who underwent or were pending revision surgery. Patient demographics including age, sex, body mass index, diabetes, and smoking as well as surgical factors including isolated versus multiple facet arthrodesis, fixation construct, and concurrent arthrodesis of other midfoot or hindfoot joints were included in the regression analysis to determine their association with nonunion. Results: The overall nonunion rate was 25.7% (26/101 cases), with a symptomatic nonunion rate of 15.8%. No significant differences in nonunion rate were identified among different surgical indications (P = 0.8682). A statistically significant difference in nonunion rate was observed between patients with isolated medial versus multiple NC facet arthrodesis (29.7% vs 16.8%, P = 0.0253, Table 1). After performing multivariate analysis adjusted for potential confounders, isolated medial NC facet arthrodesis (OR 22.9, 95% CI: 3.4-155.1, P = 0.0013, Figure 1) and diabetes (OR 13.8, 95% CI: 1.2-143.0, P = 0.0331) were significantly associated with nonunion. No significant association with nonunion was identified based on the fixation construct used or whether concurrent arthrodesis of adjacent foot joints was performed. Conclusion: This study identified a substantial rate of nonunion following NC joint arthrodesis. After regression analysis, we identified that the risk of nonunion was higher in patients with diabetes and if only the medial NC facet was included in the arthrodesis. No significant differences were observed in nonunion rates based on fixation construct or concurrent arthrodesis of adjacent midfoot joints. These results suggest that incorporating multiple facets in the NC joint arthrodesis may improve the likelihood of achieving union.