Relationship between physical activity and ankle osteoarthritis: Implications for metabolic diseases.

BACKGROUND

Regular physical activity is associated with lower cardiometabolic risk, yet musculoskeletal disorders such as ankle osteoarthritis (OA) may limit activity. This study investigated the association between radiographic ankle OA severity and habitual physical activity quantified using MET-min/week.

METHODS

In this retrospective cross-sectional study, consecutive patients evaluated for ankle OA at a tertiary referral foot and ankle clinic (Takakura stage ≥2) between June 2022 and October 2024 were included. Weightbearing ankle radiographs were used to classify OA severity (modified Takakura stage). Physical activity was assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF; vigorous, moderate, walking, and total MET-min/week). Patient-reported outcomes were assessed using the Foot and Ankle Outcome Score (FAOS). Correlations between MET-min/week and clinical parameters were evaluated using multivariable partial-correlation analyses controlling for age, sex, BMI, and pain severity (VAS), with adjustment for multiple comparisons.

RESULTS

A total of 262 patients (99 males, 163 females; mean age 66.8 years) were analyzed. Mean BMI was 26.3 kg/m². Takakura stages were: stage 2 (n = 54), stage 3a (n = 93), stage 3b (n = 52), and stage 4 (n = 63). Moderate activity MET and walking MET differed between males and females (p = 0.033 and p = 0.035, respectively). In the overall cohort, higher age correlated with lower vigorous activity MET (r=-0.155, p = 0.010) and total MET (r=-0.182, p = 0.003), and higher BMI correlated with lower vigorous MET (r=-0.129, p = 0.038), walking MET (r=-0.141, p = 0.024), and total MET (r=-0.177, p = 0.005). After adjustment for covariates, higher Takakura stage correlated with lower vigorous MET (r=-0.152, p = 0.016) and lower total MET (r=-0.127, p = 0.044). In sex-stratified analyses, Takakura stage correlated with vigorous MET in males (r=-0.226, p = 0.027) and with total MET in females (r=-0.167, p = 0.037). In Takakura stage 4, no patients reported vigorous activity, indicating a floor effect.

CONCLUSIONS

Demographic factors (age, BMI, sex) and radiographic severity of ankle OA were associated with lower self-reported physical activity (MET-min/week). Longitudinal studies incorporating objective activity monitoring and cardiometabolic endpoints are needed to clarify temporal relationships and potential metabolic implications.

LEVEL OF EVIDENCE: Level III, retrospective cross-sectional study.