Kinetic analysis of gait in adults with asymptomatic flatfoot

The aim of our study was to assess the influence of asymptomatic flatfoot on the kinetic parameters of the lower limb during gait. Methods: Individuals of both sexes were studied: 15 women [age 25 ± 5 years] and 19 men [age 25 ± 4 years] with bilateral asymptomatic flatfoot, as well as 16 women [age 26 ± 4 years] and 14 men [age 24 ± 3 years] with normal feet on both sides. A threedimensional VICON motion analysis system coupled with KISTLER dynamometric platforms was used to perform kinetic gait analysis. Results: Women with flatfoot showed significantly lower maximal relative moments in the ankle in the sagittal plane ( p < 0.05) and significantly lower maximal relative moments in the knee in the sagittal plane in the Terminal Stance ( p < 0.001). In men, a significant difference was found in terms of hip rotation moment in the transverse plane in the Mid Stance ( p < 0.01): men with normal feet showed moments of external rotation, while men with flatfoot generated internal rotational moments. Moreover, men with flatfoot showed significantly lower ( p < 0.01) maximal relative moments in the knee in the transverse plane in the Mid Stance. Conclusions: Women with flatfoot have a weakened lower limb propulsion mechanism, whereas, in men with flatfoot, there is a change in the mechanics of the lower limb in the transverse plane. Our findings cast some doubt on flatfoot as a putative risk factor for stress injuries and degenerative changes in lower-limb structures, and suggest that gender differentiation should be taken into account in the analysis and therapy of flatfoot.