# Radiographic prevalence and associated factors of hallux rigidus in a large-scale population-based cohort

## TL;DR

This study found that 23.5% of a Japanese population had hallux rigidus, a type of arthritis in the big toe joint, and identified factors like age, gout, and knee arthritis as contributors.

## Contribution

The study reports the first large-scale population-based radiographic prevalence of hallux rigidus in Japan and identifies novel associated factors.

## Key findings

- Hallux rigidus prevalence was 23.5% in a Japanese cohort with no significant sex difference.
- Older age, coastal residence, gout history, and knee osteoarthritis were independently associated with hallux rigidus.
- HR severity showed linear trends with gout and knee osteoarthritis.

## Abstract

Hallux rigidus (HR), a form of osteoarthritis (OA) affecting the first metatarsophalangeal joint, significantly impairs mobility and quality of life. Despite its clinical importance, large-scale epidemiological studies on radiographic HR prevalence and associated factors remain limited. This study investigated the radiographic prevalence of HR and its associated factors in a large, population-based Japanese cohort.

Data were obtained from 1998 participants (654 men, 1344 women) in the fifth survey of the nationwide Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. Non-weight-bearing dorsoplantar foot radiographs were assessed using the Hattrup and Johnson classification (grade 1: mild, grade 2: moderate, and grade 3: severe); HR was defined as grade ≥1. Multivariable logistic regression assessed associated factors, and the Cochran-Armitage trend test evaluated severity-related trends.

The mean age was 64.2 ​± ​12.7 years. The overall HR prevalence was 23.5 ​% (25.1 ​% in men, 22.8 ​% in women), with no significant sex difference. Unilateral and bilateral HR were 6.6 ​% and 17.0 ​% of participants, respectively. HR was classified as mild (13.3 ​%), moderate (7.0 ​%), or severe (3.3 ​%). Multivariable analysis identified older age, coastal residence, gout history, and knee OA as independent factors associated with HR. HR severity showed significant linear trends with both gout and knee OA.

This study determined the radiographic prevalence of HR of 23.5 ​% in a Japanese population. Independent factors associated with HR included older age, coastal residence, gout, and knee OA. Findings indicate that HR is multifactorial and highlight the need to explore geographic and lifestyle-related factors in addition to medical conditions.