The effect of personalized orthopedic insoles on plantar pressure during running in subtle cavus foot

Abstract

Objective: This study aims to investigate the patterns of plantar pressure distribution during running for patients with subtle cavus foot (SCF) and determine the impact of personalized orthopedic insoles with forefoot wedge on plantar pressure distribution in patients with SCF. Methods: Sixteen undergraduate participants (8 with SCF and 8 with normal arches) were recruited based on arch height index measurements. Two full-length insoles were personalized for each SCF based on plantar pressures during running, an arch support insole (ASI) and an arch support with forefoot wedge insole (AFI). Foot pressure data collected during different insole conditions in running, analyzing ten regions of footprints for peak pressure and pressure-time integral. Results: Higher peak pressures were observed in patients with SCF at the medial forefoot (p = 0.021), medial heel (p = 0.013), and lateral heel (p = 0.025), with a higher pressure-time integral also noted at the medial forefoot (p = 0.025), medial heel (p = 0.015), and lateral heel (p = 0.047) when compared to normal arches. Compared with without-insole, both the AFI and the ASI reduced peak pressure at the medial (AFI p = 0.011; ASI p = 0.024) and lateral heel (AFI p = 0.028; ASI p = 0.032). The AFI reduced peak pressure at the medial heel (p = 0.013) compared with the ASI. Both the AFI and the ASI reduced pressure-time integral at the medial forefoot (AFI p = 0.003; ASI p = 0.026), central forefoot (AFI p = 0.005; ASI p = 0.011), medial heel (AFI p = 0.017; ASI p = 0.005), and lateral heel (AFI p = 0.017; ASI p = 0.019). Additionally, the ASI reduced pressure-time integral at the big toe (p = 0.015) compared with the without-insole. Conclusion: These findings demonstrate that during running in patients with SCF, plantar pressures are concentrated in the forefoot and heel compared to the normal arch. The personalized orthotic insoles can be used to effectively redistribute plantar pressure in patients with SCF running. Incorporating a forefoot wedge to specifically address the biomechanical abnormalities associated with SCF may enhance the effectiveness of orthopedic insoles.

Keywords: Coleman block test; foot pain; forefoot valgus; heel varus; high-arched feet.

FIGURE 1

The patient with SCF characteristics: (A) Measuring forefoot valgus angle. The red solid line is the alignment of the first to fifth metatarsals head and the red dotted line is the horizontal line; (B) “peek-a-boo heel” sign, the red dashed box is the observed heel; (C) Standing position posterior view without block; (D) Coleman block test.

FIGURE 2

Three-point setup arch support structure range (Note: The horizontal dashed lines are the 13 isometric lines dividing the foot. The first point is located on the medial side of the foot, at the upper edge of the fifth isometric line; the second point is located on the lateral side of the foot, midway between the eighth and ninth isometric lines; and the third point is located on the medial side of the foot, at the upper edge of the twelfth isometric line).

FIGURE 3

Arch support insole and arch support with forefoot wedge insole: (A) Design drawing; (B) The perspective of the heel position; (C) The perspective of the forefoot position.

FIGURE 4

The footprints were divided into ten regions: big toe (BT), second toe (ST), lateral toes (LT), medial forefoot (MF), central forefoot (CF), lateral forefoot (LF), medial arch (MM), lateral arch (LM), medial heel (MH) and lateral heel (LH).