Analysis of longitudinal arch supports in stabilizing the arch of the foot.

Two orthotic devices commonly prescribed as arch supports were studied to evaluate their efficacy in stabilizing the foot. Fourteen cadaveric feet were mounted in a loading frame, and an axial load of 222, 445, or 667 N was applied while three-dimensional positions of the talus, calcaneus, navicular, and first metatarsal were monitored with a magnetic tracking system. Feet were tested with and without the use of two commonly prescribed arch supports. The two indices used to assess arch stabilization were arch height and joint rotation. Joint rotations consistently increased on load application. Significant differences were observed with Inserts 1 and 2 in metatarsal talar abduction, dorsiflexion and eversion, calcaneal talar eversion, and talar tibial dorsiflexion. Arch height significantly increased with both inserts. Contrary to previously published results, the arch supports that were studied provided measurable improvement in arch stability in a simulated standing at ease position.