Comparison of plantar pressure distribution patterns between foot orthoses provided by the CAD-CAM and foam impression methods

Foot orthotic treatment is one of the major conservative methods used to handle foot problems. Total plantar contact foot orthoses are used to reduce and redistribute peak pressures. For the fabrication of a total plantar contact foot orthosis, the computer-aided design and computer-aided manufacturing (CAD-CAM) method has been applied. In this study, the plantar foot-orthosis interface pressure data during walking were collected by the Novel Pedar-mobile in-shoe plantar pressure measuring system. The data were collected under three conditions: (i) Flat insole, (ii) foot orthosis provided by the CAD-CAM method, and (iii) foot orthosis provided by the foam impression method. The Swiss Comfort CAD-CAM foot orthotics system was used in this study. For conditions (ii) and (iii), foot shapes were collected in partial weight bearing and subtalar neutral conditions. Thirty normal subjects were recruited for this study. The plantar foot surface was divided into eight plantar foot regions and then was investigated. These regions included the heel, the medial and lateral arches, the medial, mid and lateral forefoot, the hallux, and the lateral toes. The results showed that the orthoses provided by both the CAD-CAM and foam impression methods could decrease the peak pressure and the maximum force in the heel region, and increase the peak pressure and the maximum force in the medial arch region. Both orthoses redistributed the peak pressure and the maximum force from the heel to the medial arch region. The peak pressure in the mid forefoot region was different between the orthoses provided by the CAD-CAM and foam impression methods.