Plantar pressure analysis of accommodative insole in older people with metatarsalgia

Foot pain frequently reduces physical activity and increases the risk of falls in older people. In current orthotic management of forefoot pain, metatarsal padding is the main strategy to reduce metatarsal pressure. However, pressure reductions are usually diverse and limited. The multi-step accommodative insole is fabricated by sequential foam padding on Plastazote under dynamic accommodation in daily walking. The aims of this study were to investigate the effectiveness and mechanisms of accommodative insole on plantar pressure redistribution in older people with metatarsalgia. The study was conducted on 21 old outpatients with moderate to severe metatarsalgia, using the ethylene vinyl acetate control, 9-mm flat Plastazote, and accommodative insoles with and without metatarsal and arch support. Outcome measures included pressure-related variables measured by a Pedar-X system, and pain scores assessed with a 0-10 Visual Analog Scale. The accommodative insole significantly decreased peak pressure under the metatarsal heads by 47.2% (p<0.001) and the pain scores from 8.2 to 1.1 (p<0.001). Plantar pressure analyses indicated that the effects of dynamic metatarsal contouring and cushioning on reducing peak pressure were greater than those of metatarsal padding. The temporo-spatial relationships between the toe and metatarsal head can assist in explaining an elevated metatarsal pressure and higher risk of falls in older people with toe deformities. The multi-step insole is simple in orthotic fabrication and ensures an even distribution of plantar pressure loading in walking. It can effectively relieve metatarsalgia and help to preserve regular walking activity for older people with metatarsalgia.