Custom-molded foot-orthosis intervention and multi-segment medial foot kinematics during walking

Context: Foot-orthosis (FO) intervention to prevent and treat numerous lower extremity injuries is widely accepted clinically. However, the results of quantitative gait analyses have been equivocal. The foot models used, participants receiving intervention, and orthoses used might contribute to the variability. Objective: To investigate the effect of a custom-molded FO intervention on multisegment medial foot kinematics during walking in participants with low-mobile foot posture. Design: Crossover study. Setting: University biomechanics and ergonomics laboratory. Patients or Other Participants: Sixteen participants with low-mobile foot posture (7 men, 9 women) were assigned randomly to 1 of 2 FO groups. Intervention(s): After a 2-week period to break in the FOs, individuals participated in a gait analysis that consisted of 5 successful walking trials (1.3 to 1.4 m/s) during no-FO and FO conditions. Main Outcome Measure(s): Three-dimensional displacements during 4 subphases of stance (loading response, mid- stance, terminal stance, preswing) were computed for each multisegment foot model articulation. Results: Repeated-measures analyses of variance (ANO- VAs) revealed that rearfoot complex dorsiflexion displacement during midstance was greater in the FO than the no-FO condition (F114 = 5.24, P=.O4, partial r|2 = 0.27). Terminal stance repeated-measures ANOVA results revealed insert-by-insert condition interactions for the first metatarsophalangeal ¡oint complex (F114=7.87, P=.O1, partial if = 0.36). However, additional follow-up analysis did not reveal differences between the no-FO and FO conditions for the balanced traditional ortho- sis (F, 14 = 4.32, P = .O8, partial if = 0.38) or full-contact orthosis (F1i14 = 4.10, P=.O8, partial if = 0.37). Conclusions: Greater rearfoot complex dorsiflexion during midstance associated with FO intervention may represent improved foot kinematics in people with low-mobile foot postures. Furthermore, FO intervention might partially correct dysfunctional kinematic patterns associated with low-mobile foot postures.