Alterations in plantar pressure with different walking boot designs

Background: Specialized walking devices, such as total contact casts and removable walking boots, have been shown to be effective noninvasive treatment options for plantar ulcers. Attempts at improving patient compliance frequently lead to new boot designs; however, the effect of the design modifications on plantar pressures or on the contralateral limb often is unknown. The purpose of this study was to determine the effect of different walking-boot calf heights and rocker sole designs on regional plantar pressures, as well as, on contralateral limb loading during walking. Methods: Twenty-six subjects, 20 to 54 years of age, without foot pathology were tested using four different configurations: high calf, rocker sole (HCR); low calf, rocker sole (LCR); low calf, modified rocker sole (LCMR), and shoe. Peak pressures, pressure-time integrals, and contact areas were measured using the Novel Pedar-X insole pressure measurement system. Average peak force was calculated for the contralateral limb. Results: Greatest forefoot peak pressure reduction was found in the HCR group (37.3% reduction compared to shoe condition), followed by 31.6% and 19.8% in the LCR and LCMR groups, respectively (p < 0.0001). Forefoot pressure-time integrals were reduced for HCR and LCR (22.1% and 21.5%, respectively) compared to the LCMR (13.0%) (p < 0.0001). Conclusions: Isolated modifications in walking boot designs resulted in plantar pressure modifications. LCR and LCMR designs favorably altered plantar pressures, but of a lesser magnitude than the HCR design. If lower calf, lower sole walking boot designs are recommended because of anticipated improvement in patient compliance, healing times may be prolonged.