A research team examined the effects of different inverted angles of foot orthoses on walking kinematics in women with flexible flatfeet. They found that the ankle joint was the most affected joint by the application of inverted foot orthoses in all measured variables, rather than the knee or the hip joints. Significant changes were found in ankle internal rotation, external rotation, plantarflexion, and dorsiflexion angles, which is in line with those of previous studies.
An inverted orthosis is a type of rigid foot orthosis designed to aid in controlling high degrees of foot pronation. The positive mold of the inverted orthoses is poured with different degrees of inversion compared to the vertical alignment of a standard orthoses.
Thirty-one adult women with flexible flatfeet, 18-35 years old, participated in the study. Kinematic data of the hip, knee, and ankle were collected via a motion-capture system during walking under three test conditions in random order: with shoes only; with 15-degree inverted orthoses; and with 25-degree inverted orthoses.
Compared to the shoes only condition, both the 15-degree and 25-degree inverted orthotic conditions significantly decreased the maximum ankle plantarflexion angle during loading response, maximum ankle dorsiflexion angle during mid-stance, maximum ankle external rotation angle, and maximum ankle internal rotation angle, according to the study.
The maximum ankle plantarflexion angle at toe-off showed a significant decrease with the 25-degree inverted angle orthosis compared to both the 15-degree inverted angle and shoes-only conditions. No significant differences were found in the knee kinematic variables, maximum hip extension angle, and maximum hip adduction angle between test conditions.
Using inverted orthoses at 15-degree and 25-degree inverted angles resulted in significant changes in ankle joint kinematics during walking. A 25-degree inverted angle orthosis significantly decreased ankle plantarflexion during push-off, potentially impacting gait mechanics. This suggests that a smaller inverted angle may be more effective for managing flexible flatfeet in adult women, the authors concluded.
The open-access study, “Effect of different foot orthosis inverted angles on walking kinematics in females with flexible flatfeet,” was published in the Journal of Multidisciplinary Healthcare.