Abstract
BACKGROUND: Hallux rigidus (HR) is a common osteoarthritis of the first metatarsophalangeal joint. However, the epidemiology and risk factors of this pathology have yet to be clarified. METHODS: We have been conducting cohort studies among individuals over 50 years old every 2 years since 1997. This study analyzed data from the 7th to 10th checkups in 2009, 2011, 2013, and 2015. We investigated the prevalence of HR and its risk factors in a total of 604 individuals (mean age, 67.1 ± 6.4 years; 208 men, 396 women). Radiographic HR was defined as Hattrup and Johnson classification grade 1 or higher. Knee osteoarthritis (KOA) was scored according to the Kellgren-Lawrence grading system. Radiographic KOA was defined as grade 2 or higher. Cases with a hallux valgus (HV) angle of 20° or higher were defined as showing HV. Statistical analyses were performed using the Kruskal-Wallis test, Fisher's exact test, logistic regression modeling, and the Cochran-Armitage trend test. All p-values presented are two-sided and values of p < .05 were considered statistically significant. RESULTS: The prevalence of HR was 26.7% (161/604). Rates of grade 0, 1, 2, and 3 HR according to the Hattrup and Johnson classification were 73.3% (443/604), 16.4% (99/604), 8.0% (48/604), and 2.3% (14/604), respectively. Overall ratio of symptomatic HR was 8.1%. Univariate analysis revealed KOA, gout attack (GA), and HV as significantly associated with HR. The same factors were confirmed as independent risk factors for HR in multivariate analysis. All parameters were significantly associated with HR. Odds ratios of KOA, HV, and GA for HR were 1.73, 3.98, and 3.86, respectively. The presence or absence of KOA was significantly associated with severity of HR. CONCLUSIONS: This study revealed that the prevalence of HR in the elderly (≥50 years) was 26.7%. KOA, HV, and GA were independent risk factors for HR. KOA was associated with severity of HR.