A study of the effect of wear on the pressure-relieving properties of foot orthosis

Abstract

There is little comparative data available to assist choice of materials for the manufacture of orthoses, and there have been few objective studies comparing insole designs. This study has compared two materials, PPT and SPENCO, and assessed one design of insole together with a commonly used variation of that design. Both materials and designs have been tested for effectiveness against each other and against themselves following a period of continuous wear. The pedobarograph was used to measure the changes in pressure. Seven subjects, with a high pressure pattern under the second metatarsal head of one foot, wore a series of four insoles in random order for 1 month each. The four insoles were made to the same pattern for each patient, two of PPT and two of SPENCO, each with a U'd plantar metatarsal pad. In one insole of each material, the U-shaped cut-out was filled with sponge. Pedobarograph recordings were taken, barefoot and with the insole taped to the foot, at issue and after 1 month of wear for each insole. Results show that all the insoles were effective in reducing pressure and force under the areas measured ( P < 0.0001). There were no significant differences in pressure relief between new and old insoles, but the insoles with a sponge button had different characteristics from those without.