The effect of foot orthoses with forefoot cushioning or metatarsal pad on forefoot peak plantar pressure in running

Abstract

Background: Foot orthoses are frequently used in sports for the treatment of overuse complaints with sufficient evidence available for certain foot-related overuse pathologies like plantar fasciitis, rheumatoid arthritis and foot pain (e.g., metatarsalgia). One important aim is to reduce plantar pressure under prominent areas like metatarsal heads. For the forefoot region, mainly two common strategies exist: metatarsal pad (MP) and forefoot cushioning (FC). The aim of this study was to evaluate which of these orthosis concepts is superior in reducing plantar pressure in the forefoot during running. Methods: Twenty-three (13 female, 10 male) asymptomatic runners participated in this cross-sectional experimental trial. Participants ran in a randomised order under the two experimental (MP, FC) conditions and a control (C) condition on a treadmill (2.78 ms-1) for 2 min, respectively. Plantar pressure was measured with the in-shoe plantar pressure measurement device pedar-x®-System and mean peak pressure averaged from ten steps in the forefoot (primary outcome) and total foot was analysed. Insole comfort was measured with the Insole Comfort Index (ICI, sum score 0-100) after each running trial. The primary outcome was tested using the Friedman test (α = 0.05). Secondary outcomes were analysed descriptively (mean ± SD, lower & upper 95%-CI, median and interquartile-range (IQR)). Results: Peak pressure [kPa] in the forefoot was significantly lower wearing FC (281 ± 80, 95%-CI: 246-315) compared to both C (313 ± 69, 95%-CI: 283-343; p = .003) and MP (315 ± 80, 95%-CI: 280-350; p = .001). No significant difference was found between C and MP (p = .858). Peak pressures under the total foot were: C: 364 ± 82, 95%-CI: 328-399; MP: 357 ± 80, 95%-CI: 326-387; FC: 333 ± 81 95%-CI: 298-368. Median ICI sum scores were: C 50, MP 49, FC 64. Conclusions: In contrast to the metatarsal pad orthosis, the forefoot cushioning orthosis achieved a significant reduction of peak pressure in the forefoot of recreational runners. Consequently, the use of a prefabricated forefoot cushioning orthosis should be favoured over a prefabricated orthosis with an incorporated metatarsal pad in recreational runners with normal height arches.