Epidemiology and Impact of Accessory Navicular on Physical Function in the General Population: Insights From a Large Population-Based Cohort ROAD Study.

BackgroundThe accessory navicular is a common anatomical variant of the foot that may become symptomatic and occasionally require treatment, particularly in younger individuals. Recent evidence indicates that accessory navicular may be associated with posterior tibial tendon dysfunction in middle-aged and elderly individuals, potentially affecting physical function. However, research on its impact in this demographic remains limited. This study aims to assess the epidemiology and impact of accessory navicular, particularly type 2, on physical function in the general population.MethodsData from the fifth Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study were analyzed, including foot radiographs and physical examinations from 1995 participants. The presence and type of accessory navicular were determined, and physical function was assessed through stabilometer measurements, walking speed tests, and locomotive syndrome risk tests. In addition, the relevant items related to balance and falls were extracted from the structured interviews and analyzed for the relationship with the accessory navicular.ResultsThe prevalence of accessory navicular was higher in females (49.9%) than in males (43.2%), with type 2 being the most frequent type. The analysis revealed a high degree of bilateral symmetry, with 79.5% of males and 76.7% of females showing the same type of accessory navicular or absence thereof on both sides. No significant differences were found in physical performance measurements between feet with and without type 2 accessory navicular. Notably, a higher history of falls was associated with bilateral type 2 accessory navicular.ConclusionsThis study provides insights into the prevalence and type distribution of accessory navicular in the general population. While type 2 accessory navicular did not show significant impacts on physical performance, its association with a history of falls suggests potential implications for dynamic balance ability, warranting further investigation.Levels of Evidence:Level III retrospective case-control study.