Effects of different customized foot orthoses on isolated subtalar arthrodesis

Background Studies describe subtalar and ankle arthrodesis as a factor altering the biomechanics of the foot during walking [1-3]. Furthermore, foot orthoses (FOs) are also recognized for their actions on the dynamics of the foot [4] but not for their actions on an isolated subtalar arthrodesis (ISA). Previous studies have shown that depending on the type of FOs [5] and along the comfort felt by the subject [6], the variations induced by different FOs were significantly different. The aim of this study was to compare the effects of different types of FOs on gait analysis with an ISA. Two subjects with ISA were volunteers for one session of three repeated measures: without FOs (Control), with Classical FOs (FOsC) and with Molded FOs (FOsM). After a clinical examination, these two types of FOs are custom-made including same posting. We compared walking variations through the Latero-Medial Index (LMI) on force platform. Four data’s have been compared: Latero-Medial Force Index (LMFI), LateroMedial Area Index (LMAI) together with observation of these index at 100ms which correlate with hind foot activity phase during walking [7]. The perception of comfort was evaluated by using previously established footwear comfort measures [6]: 100mm visual analog scale (VAS).