A Cross-sectional Analysis of Radiographic Ankle Osteoarthritis Frequency and Associated Factors: The Johnston County Osteoarthritis Project

Objective. Because there are no epidemiologic data regarding the frequency of ankle osteoarthritis (OA) in a general population, we sought to analyze this disabling condition in a large, well-characterized, community-based cohort of older individuals. Methods. Cross-sectional data, including ankle radiographs, were from the most recent data collection (2013-2015) of the Johnston County OA Project. Radiographic ankle OA (rAOA) was defined as a Kellgren-Lawrence arthritis grading scale of >= 2 on weight-bearing lateral and mortise radiographs. The presence of pain, aching, or stiffness in the ankles as well as history of ankle injury (limiting ability to walk for at least 2 days) were assessed. Chi-square statistics (categorical variables) and Student t tests (continuous variables) were used to compare all participant characteristics by rAOA status. Joint-based logistic regression models with generalized estimating equations were used to examine associations of rAOA and covariates of interest [age, body mass index (BMI), sex, race, ankle symptoms, and injury history]. Results. Of 864 participants with available data, 68% were women, 34% were African American, with a mean age of 72 years and BMI of 31 kg/m(2). Nearly 7% of this sample had rAOA. Increasing age, high BMI, history of ankle injury, and presence of ankle symptoms were all independently associated with greater odds of having rAOA; no significant differences were seen by sex or race. Conclusion. The frequency of rAOA was higher than estimates generally quoted in the literature. While injury was an important contributor, other factors such as age, BMI, and symptoms were also significantly associated with rAOA.