The effect of eliminating leg length difference on plantar foot pressure distribution in patients wearing forefoot offloading shoe

Abstract

Background and purposeElevated heel construction offloads the forefoot after surgery. However, side-to-side height difference alters limb kinetics, whereas leg-length equalizing-sole at non-operated side may have beneficial effects on foot loading. The purpose of this study was to characterize leg-length equalizing sole effect on bilateral plantar pressures when using heel-lift forefoot-offloading shoe. Materials and methodsTwenty men were tested walking. Plantar peak pressures (PP) and pressure-time integrals (PTI) in the forefoot-offloading shoe and in contralateral running shoe were compared between two conditions: one with- and the other without leg-length equalizing sole elevation at the running shoe. ResultsAdding leg-length equalizing sole to the running shoe resulted in the following changes in the forefoot-offloading shoe: increased lateral midfoot PP (8.7%, p=0.03), increased lateral midfoot (11.3%, p=0.05) and lateral metatarsals PTI (10.3%, p=0.04), and decreased medial and lateral heel PTI (>5%, p=0.02). These changes were non-significant when applying a Bonferroni correction. Changes in the running shoe were: increased medial midfoot (20.5%, p=0.03) and decreased 2nd and lateral metatarsals PP (23%, p<0.01). PTI increased in medial and lateral heel (>25%, p<0.01), medial midfoot (63.2%, p<0.01) and lateral midfoot (9.2%, p=0.04) and decreased in 2nd and lateral metatarsals (>24.5%, p<0.01). ConclusionLeg-length equalizing sole at contralateral running shoe in subjects wearing forefoot-offloading shoe results in lateral load shift alongside heel pressure attenuation within the forefoot-offloading shoe, which is beneficial during first month after medial forefoot surgery. Reciprocal medial load-shift in the elevated running shoe itself should yet be considered when bilateral medial forefoot pathology is present.