Generally, flat feet are defined as feet with an abnormally low medial arch height as measured during weight-bearing stance). Plantar pressure measurements are used to quantify dynamic and static pressures as a measure of foot activity during walking. Plantar pressure evaluation is also used to assess the effectiveness of footwear and orthotic interventions.). The aim of this study was to evaluate plantar foot pressure effect on the customized foot orthosis to determine its effectiveness in improving foot posture and reduce strain on the plantar fascia for patients with flat foot condition
In this study, we estimated plantar pressures of a subject who is 80 kg with a foot length of 270 mm and classified him as having flat feet (having a navicular height of less than 37 mm and a rear foot angle of more than 9° of valgus).Plantar foot pressure data were recorded using the Solid works Simulink Software. For each pressure measurement trial, three plantar regions on the foot were identified: the forefoot region, midfoot region and heel region.
In this study, the peak pressure and the pathway of center of pressure were measured of the subject walking without the aid of a foot orthosis and walking with the foot orthosis on . The independent t-test was used to examine the effectiveness of the foot orthosis in preventing the center of mass from shifting medially, which is essential for maintaining proper alignment and stability in patients with flat feet.
RESULTS
Comparison of plantar foot pressure between the 3 regions during heel strike ,midstance and toe off.
- Loads and fixtures
- Plantar foot pressure during heel strike is concentrated at the heel.(142,847N/m2)
- Plantar foot pressure during midstance is distributed 57% at the heel and 26% at the arch.
- Plantar foot pressure during toe off is concentrated more at the forefoot in patients with flat foot.(145,455N/m2)
- Study results
The maximum stresses remained below the material's yield strength(60MPa) during heel strike, midstance and toe off ensuring that the ABS-PC behaves predictably under load without permanent deformation.
- The orthosis demonstrated excellent elastic recovery characteristics, returning to its original shape after load removal, which indicates good material performance and longevity. Maximum displacements remained within acceptable limits (e.g., ≤ 5 mm), confirming that the orthosis provides adequate support without excessive flex or instability during use.
- The orthosis exhibited elastic recovery characteristics, with minimal permanent deformation post-load removal.
- Fatigue
After 1,000,000 cycles of loading and unloading, in order to mimic months of walking, the load factor remained more the 1.0(load factor less than 1.0 indicates failure).
The orthosis should is able to endure constant use and daily wear and tear without degrading quickly.
