The association between toe grip strength and osteoarthritis of the knee in Japanese women: A multicenter cross-sectional study

We evaluated the relationship between altered foot function and knee osteoarthritis through a specific comparison of toe grip strength in older women with and without knee osteoarthritis. Participants were 120 women with knee osteoarthritis (OA group) and 108 healthy community-dwelling women with no history of knee pain and lower limb surgery (control group). The following factors and outcome variables were included in our analysis: measured toe grip strength, isometric knee extension strength, the timed Up-and-Go, and the WOMAC scale. Between-group differences were compared using unpaired t-tests for descriptive characteristics and outcome measures. Pearson's correlation coefficients between toe grip strength and age, body mass index, and other outcome measures were calculated. Multiple logistic regression analysis was used to evaluate the independence of toe grip strength and knee osteoarthritis. Compared to the control group, participants in the OA group were older, heavier, and had a higher body mass index. Toe grip strength and isometric knee extension strength were lower and the timed Up-and-Go longer for the OA group than the control group. Toe grip strength was correlated with age negatively and isometric knee extension strength positively in the OA group and to age and the timed Up-and-Go negatively, and isometric knee extension strength positively in the control group. Multiple logistic regression analysis revealed that body mass index, isometric knee extensor strength, and toe grip strength were independently associated with knee osteoarthritis. Our findings indicate a probable association between altered forefoot function and the incidence or progression of knee osteoarthritis. Increasing toe grip strength might provide a practical intervention for patients with knee osteoarthritis.