Background
Orthotic wedges with medial posting of the forefoot and rearfoot have been shown to be effective in controlling excessive foot pronation in people with plantar fasciitis (PF), however the best prescription remains unclear.
Research question: The aim of this study was to determine the biomechanical effects of two designs of orthotic wedges within a shoe on the hip, knee, rearfoot, and forefoot kinematics in individuals with PF.
Methods
Thirty-five participants with PF were recruited. They were asked to walk under three randomized conditions; shod, shod with orthotic wedges with foot assessment technique 1 (W1), and shod with orthotic wedges from a new assessment technique (W2). Biomechanical outcomes included lower limb and multi-segment foot kinematics in each subphase of the stance gait, including contact phase, midstance phase, and propulsive phase.
Results
Compared with shod, the W1 significantly increased rearfoot dorsiflexion, decreased peak forefoot dorsiflexion, and peak rearfoot eversion during the contact phase. In addition, W1 increased rearfoot inversion, decreased hallux dorsiflexion, and peak hallux dorsiflexion during the propulsive phase. For W2, the wedge significantly decreased peak knee internal rotation, decreased forefoot abduction, peak forefoot dorsiflexion, and peak rearfoot eversion during the contact phase. In addition, W2 increased rearfoot inversion, decreased hallux dorsiflexion, and decreased peak hallux dorsiflexion during the propulsive phase. When comparing W1 and W2, W1 showed greater rearfoot dorsiflexion during the contact phase.
Significance: These findings suggest that the use of forefoot varus wedges, and the combination of forefoot and rearfoot varus wedges, can change the lower limb kinematics, the multi-segment foot kinematics estimated using markers fixed to the shoe, and the relative length of the plantar fascia which can be associated with a reduction in pain and symptoms during walking.
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