Effect of foot orthoses on the biomechanics of stair ascent and descent in chronic metatarsalgia.

In individuals with musculoskeletal disorders such as chronic metatarsalgia, foot orthoses (FOs) are frequently prescribed to reduce plantar pressure, improve foot function and alleviate pain. During walking, medially wedged FOs (MWFO + MPs) with a metatarsal pad are more effective than standard FOs (SFOs) in reducing plantar pressure under the metatarsal heads. As stair ambulation involves higher physical demands than walking and modifies plantar loading, we questioned whether FOs remain effective during more challenging tasks. This study aimed to determine whether MWFO + MPs reduce peak plantar pressure under the metatarsal heads compared to SFOs during stair ambulation in individuals with chronic metatarsalgia. A secondary objective was to examine the effects of these FOs on lower limb 3D joint angles and moments. Twenty-two individuals (16 females and 6 males) with chronic metatarsalgia were recruited to participate in this cross-sectional descriptive study. Participants ascended and descended stairs under three conditions: (1) Shoe-only, (2) SFOs, and (3) MWFO + MPs. Peak plantar pressure, midfoot, ankle, knee, hip angles and moments were compared across conditions using repeated-measures ANOVAs and statistical parametric mapping. Both FOs reduced plantar pressure under the metatarsal heads and heel compared to shoe-only during stair ambulation. MWFO + MPs increased plantar pressure under the medial midfoot, decreased midfoot dorsiflexion, ankle plantarflexion angles compared to shoe-only. MWFO + MPs were more effective than SFOs in reducing peak plantar pressure under the 1st metatarsal head and modifying lower limb joint angles and moments. These findings extend the known biomechanical benefits of FOs in individuals with chronic metatarsalgia during more demanding tasks.