Custom-made foot orthoses with and without heel plugs and their effect on plantar pressures during treadmill walking

Background: Foot orthoses have consistently demonstrated an improvement in pain scores for plantar fasciitis. The fabrication of custom-made foot orthoses (CFOs) can vary between clinicians and may include the use of different materials and casting techniques. This cross-sectional study's objective was to quantify plantar pressure for two CFOs, one with a heel plug (HP) and one without. Methods: Fourteen healthy participants (8 men and 6 women; 35.4 +/- 7.7 years) were cast by the same practitioner. Both CFOs were made with the same materials and specifications, except for the HP orthosis, which replaced hard material under the heel with a softer blue PORON (R) plug for added cushioning. Plantar pressures were recorded during treadmill walking for both devices in a running shoe. Average pressure, peak pressure, and pressure contact area were determined for three regions of the foot: hindfoot, midfoot, and forefoot. A paired samples t-test determined differences in each region (P < 0.05). Results: The HP orthosis reduced the overall means of average pressure, peak pressure, and pressure contact area in the hindfoot while tending to increase these measures in the midfoot and forefoot. The three measures showed statistically significant decreases in the hindfoot, whereas a statistically significant increase was seen in average and peak pressures in the midfoot (P < 0.05). Conclusions: CFOs with HPs are more effective than regular CFOs in offloading plantar pressures in the hindfoot while increasing pressures in the midfoot. This is an important finding because offloading the hindfoot is critical in pathologies such as plantar fasciitis to decrease pain and increase function.