The effect of hydrodynamic insole on foot kinematics in individuals with flexible flatfoot: Case series using a single-subject design

Abstract

The medial longitudinal arch of the foot is a dynamic structure while walking. The mobility of this structure in people with flexible flatfoot is partially or completely absent. The aim of this study was to investigate the efficacy of an insole that was designed to retrieve the medial longitudinal arch mobility in people with flatfoot. The study was a case series using a single-subject design. This single-subject design study was based on three subjects with flexible flatfoot. This study was designed in two phases: the baseline phase and the intervention phase. Each phase included five measurement sessions that were done in 5 consecutive weeks. We used the celeration-line method to detect the significant differences between the phases. Significant differences were recorded in the walking velocity, step length, and medial longitudinal arch mobility parameters when using the hydrodynamic insole. The results of this study showed that using the hydrodynamic insole may have a positive effect on the foot kinematics and gait parameters in people with flexible flatfoot.

Designing and fabricating a novel medical insole with universal fluid layer with auto-customizability

“…However, the insole presented in this research is prefabricated and ready to be delivered to patients and healthy people. Another characteristic of the insole with universal fluid layer is that it can be suitable for those with flat foot in accordance with the research by Barati et al, 25 due to possessing fluid displacement ability.…”

“…In examining medical insoles, two views on improving the design of insole geometry and improving its material can be evaluated based on experimental test methods [15][16][17] and numerical analysis. [18][19][20] Various medical insoles have been developed based on these two views, including custom-made medical insoles, 21 smart medical insoles, [22][23][24] hydrodynamic medical insoles, 25 Rockertype insoles, 26 multi-plug insoles, 27 shock absorbent medical insoles, 28 vibrating medical insoles, 29 shear reducing insoles, 30 and balance enhancer insoles. 31 Previous studies have shown that if the insole geometry is according to the plantar geometry (custom-made insoles), the person feels more comfortable, and this type of insoles reduces the pressure more considerably than flat insoles.…”

“…16,17,35 On the other hand, use of hydrodynamic insoles in the recent research suggests changes in the approach of fabricating insoles. Barati et al 25 introduced a hydrodynamic insole made of silicone for patients with flat foot, in which the fluid has been used. In this type of insole, two chambers connected to each other through a channel have been devised: one under the ball of the foot (from the metatarsophalangeal joints to distal end of the toes) and the other under the longitudinal arch of the foot, in which oil has been utilized.…”

“…The hydrodynamic medical insoles, in which oil has been used locally as a fluid in a part of the insoles, are the only similar presented insoles in this area. 25 Usage of silicone and silicone gel as a universal fluid in these insoles has caused conversion of this insole to a custom-made insole according to the plantar geometry of a person automatically. As was mentioned, custom-made insoles provide greater comfort and lower pressure than flat insoles for individuals.…”

Comparative Study of the Effects of Customized 3D printed insole and Prefabricated Insole on Plantar Pressure and Comfort in Patients with Symptomatic Flatfoot

“…By optimizing the traditional support structure, it can be more suitable for the patient’s plantar structure, thereby reducing damage and improving comfort [10,11]. However, there are currently few studies on customized insoles for patients with flatfoot symptoms, and the number of cases is small [12,13]. Researchers have overlooked the negative effects of inappropriate traditional insoles on patients with flatfoot deformity.…”